Patent Publication Number: US-2022220614-A1

Title: Precursor supply chamber

Description:
FIELD OF THE INVENTION 
     The present invention relates to a precursor supply chamber and more particularly to a precursor supply chamber for accommodating a precursor container in connection with atomic layer deposition method according to preamble of claim  1 . The present invention also relates to a precursor supply cabinet for a precursor supply system and more particularly to precursor supply cabinet according to preamble of claim  13 . 
     BACKGROUND OF THE INVENTION 
     Precursor gases are supplied from precursor containers or precursor vessels to a reaction chamber of an atomic layer deposition apparatus. A substrate to be processed is further placed into the reaction chamber such that it may be processed with the precursor gases according to principles of atomic layer deposition. The precursor containers are conventionally arranged into a ventilated space and precursor conduits extend from the precursor containers in the ventilated space towards the reaction chamber. The precursors are further supplied to the reaction chamber in heated state. Therefore, the precursor containers and the precursor conduits are insulated and heated with heating elements for maintaining the precursors at the elevated temperature in the ventilated space and for preventing decrease of precursor temperature and condensation. 
     One of the disadvantages associated with the prior art is that all precursor containers and precursor conduits have to be separately insulated and heated in the ventilated space. This makes controlling the temperatures difficult and complicated. Different precursor materials require different temperatures and therefore each precursor container and precursor conduit must be separately insulated and heated. However, the heated precursor containers and precursor conduits affect each other making the control of temperatures difficult. 
     BRIEF DESCRIPTION OF THE INVENTION 
     An object of the present invention is to provide a precursor supply chamber and a precursor supply cabinet so as to overcome or at least alleviate the prior art disadvantages. 
     The objects of the invention are achieved by precursor supply chamber which is characterized by what is stated in the independent claim  1 . The objects of the invention are further achieved by precursor supply cabinet which is characterized by what is stated in the independent claim  13 . 
     The preferred embodiments of the invention are disclosed in the dependent claims. 
     The present invention is based on the idea of providing a precursor supply chamber for accommodating a precursor container in connection with an atomic layer deposition apparatus. The precursor supply chamber comprises chamber walls defining a chamber space inside the precursor supply chamber. The precursor supply chamber further comprises a chamber door assembly arranged to close the precursor supply chamber in gas tight manner, a first heating element provided to the precursor supply chamber and arranged to heat the precursor container inside the chamber space of the precursor supply chamber, and a gas tight precursor connection provided to the chamber walls for supplying precursor from the precursor container outside the precursor supply chamber. 
     The precursor supply chamber further comprises a precursor container holder inside the precursor supply chamber for holding the precursor container, the first heating element is provided to the precursor container holder for heating the precursor container held by the precursor container holder. Accordingly, the precursor container is placed on the precursor container holder inside the chamber space. The precursor container may be placed on the heated precursor container holder inside the chamber space enabling heating the precursor container. 
     The precursor supply chamber also comprises a precursor supply element arranged to control precursor supply from the precursor container to outside the precursor supply chamber via the gas tight precursor connection. The precursor supply element is arranged above the precursor container holder inside the precursor supply chamber. The precursor container is connected to the precursor supply element with a precursor container supply line extending from the precursor container to the precursor supply element. 
     The precursor supply chamber further comprises a second heating element provided above the precursor container holder in the precursor supply chamber. 
     Based on the above mentioned, the precursor container holder may be arranged to two lower part of the chamber space of the precursor supply chamber and the precursor supply element may be arranged to the upper part of the chamber space and/or above the precursor container or the precursor container holder. Accordingly, precursor gas may be supplied from the precursor container in the lower part of the chamber space to the precursor supply element in the upper part of the chamber space. This is advantageous, as the heat rises towards the upper part of the chamber space in the precursor supply chamber and thus precursor gas flows in a direction of increasing temperature gradient from the precursor container inside the chamber space. 
     Accordingly, the second heating element may provide and/or enhance the increasing temperature and temperature gradient inside the chamber space towards the upper part of the chamber space. This allows ensuring that the precursor gas may be supplied from the precursor container in a direction the increasing temperature gradient. The increasing temperature gradient may be achieved by providing a higher temperature or by utilizing higher heating power in the second heating element than in the first heating element. Increasing temperature gradient prevents the gaseous precursor from condensing during supply. 
     Further, the precursor supply chamber accommodates the precursor container in a gas tight chamber in which the precursor container is heated with the first heating element. Thus, the temperature of the precursor container and precursor may be controlled in detail as the precursor container is arranged in controlled atmosphere inside the gas tight precursor supply chamber. 
     In the context of this application, in relation to precursor supply chamber gas tight means that there is substantially no gas flow between the chamber space inside the precursor supply chamber and the outside of the precursor supply chamber. Accordingly, gas tight means that leakage flow is less than 5 standard litres per minute (slm) into the chamber space of the precursor supply chamber from outside of the precursor supply chamber, or between the chamber space and the outside of the precursor supply chamber. Preferably, the gas tight means that the above mentioned leakage flow between 0 to 5 slm, or less than 3 slm, or more preferably less than 1 slm. 
     Similarly, in the context of this application, in relation to the precursor connection gas tight means that there is substantially no gas flow between the inner space of the precursor connection and the outside of the precursor connection. Accordingly, gas tight means that leakage flow is less than 5 standard litres per minute (slm) into the inner space of the precursor connection from outside of the precursor connection, or between the inner space and the outside of the precursor connection. Preferably, the gas tight means that the above mentioned leakage flow is between 0 to 5 slm, or less than 3 slm, or more preferably less than 1 slm. The precursor connection may be preferably provided vacuum tight for forming a vacuum tight precursor connection. Vacuum tight means that the leakage flow is less than 0,5 slm or less than 0,1 slm or preferably the leakage is substantially 0 slm. 
     In one embodiment, the first heating element is provided to lower part of the chamber space of the precursor supply chamber. Arranging the first heat element in the lower part of the chamber space enables controlling the temperature inside the chamber space and thus the temperature of the precursor container in detail. Due to natural convection, heated gas rises upwards in the chamber space and thus the lower temperatures inside the chamber space may be controlled with the first heating element. 
     In one embodiment, the precursor supply chamber comprises a bottom wall. 
     In one embodiment, the precursor container holder is arranged at bottom of the chamber space of the precursor supply chamber. Thus, there is enough room for the precursor container and the heating of the precursor container may be carried out such that heat rises upwards in the chamber space. 
     In another embodiment, the precursor container holder is arranged to lower part of the chamber space of the precursor supply chamber. 
     In a yet alternative embodiment, the precursor container holder is arranged on bottom wall of the precursor supply chamber or in the vicinity thereof. This enables maximising the inner space of the chamber space and heating the precursor container from underneath. 
     In one embodiment, the precursor supply chamber comprises a precursor supply element arranged to control precursor supply from the precursor container to outside the precursor supply chamber via the gas tight precursor connection. The precursor container is connected to the precursor supply element with a precursor container supply line extending from the precursor container to the precursor supply element. 
     In one embodiment, the precursor supply chamber comprises one or more gas valves arranged to control precursor supply from the precursor container outside the precursor supply chamber via the gas tight precursor connection. 
     In another embodiment, the precursor supply element comprises one or more gas valves arranged to control precursor supply from the precursor container outside the precursor supply chamber via the gas tight precursor connection. 
     The precursor container is connected to the precursor supply element and the gas valves with the precursor container supply line for supplying precursor from the precursor container to the precursor supply element and further t outside the precursor supply chamber via the gas tight precursor connection. 
     In one embodiment, the precursor supply element is arranged to upper part of the chamber space of the precursor supply chamber. 
     In yet another embodiment, the precursor supply chamber comprises a top wall, and the precursor supply element is arranged in connection with the top wall. 
     In one embodiment, the precursor supply chamber comprises the second heating element provided to the upper part of the chamber space of the precursor supply chamber. 
     In a yet alternative embodiment, the precursor supply chamber comprises the second heating element provided above the precursor container holder in the precursor supply chamber. 
     In one embodiment, the second heating element is provided to the top wall or in connection with the top wall of the precursor supply chamber. 
     In another embodiment, the second heating element is provided to the precursor supply element. 
     Providing the second heating element to the precursor supply element enables heating the precursor gas as it flows through the precursor supply element. Thus, temperature of the precursor gas may be increased downstream of the precursor container. 
     In one embodiment, the precursor supply chamber comprises a third heating element provided to the gas tight precursor connection. 
     The third heating element enables heating the precursor in the gas tight precursor connection downstream of the precursor supply element. Thus, temperature of the precursor gas may be further increased downstream of the precursor supply element for providing the increasing temperature gradient from the precursor container via the precursor supply element to the gas tight precursor supply connection. 
     In one embodiment, the chamber walls of the precursor supply chamber are made of metal such that the metal chamber walls define the chamber space of the precursor supply chamber. 
     In another embodiment, the chamber walls comprise a metal inner wall layer defining the chamber space of the precursor supply chamber. 
     In yet another embodiment, the chamber walls comprise a metal inner wall layer and a metal outer wall layer, the metal inner wall layer defining the chamber space of the precursor supply chamber. 
     The metal chamber walls or metal inner wall layer provide wall structure which does not cause particles into the chamber space. Further, the meat wall structure may provide thermal mass which may store thermal energy for minimizing temperature variations inside the chamber space. The metal wall or meta inner layer may be for example made of steel or stainless steel or aluminium. 
     In one embodiment, the chamber walls are provided with thermal insulation. The thermal insulation prevents thermal energy from escaping from the chamber space and minimizes temperature variations inside the chamber space due to outside conditions. 
     In another embodiment, the chamber walls are provided with thermal insulation layer arranged between the metal inner wall layer and the metal outer wall layer. 
     Further in another embodiment, the chamber walls comprise metal surface layers and a thermal insulation encapsulated inside the chamber walls between the metal surface layers. 
     Providing the thermal insulation or thermal insulation layer between the inner wall layer and outer wall layer or encapsulating the thermal insulation between the surface layers of the chamber walls enables keeping the thermal insulation away from the chamber space such that thermal insulation is not deteriorated or damaged during using the precursor supply chamber. Further, particles from the thermal insulation are not released to the chamber space. 
     In one embodiment, the chamber door assembly comprises a chamber door and a sealing member arranged to seal the precursor supply chamber when the chamber door is in closed position. 
     The sealing member may be provided to the door or to the door assembly or to the door opening, meaning edges of the door opening, for sealing the door assembly when the chamber door is closed. Thus, the sealing member may be provided enhance of provide the gas tightness of the door assembly for closing the precursor supply chamber in gas tight manner. 
     In one embodiment, the chamber door assembly comprises the chamber door and a closing mechanism arranged to pre-stress the chamber door to the closed position and/or lock the door to the closed position. 
     The closing mechanism may comprise lock, latch or the like for closing or pre-stressing the door to the closed position. The closing mechanism may also comprise hydraulic cylinder or spring or elastic pre-stressing means for pre-stressing the door to the closed position. In some embodiment, the sealing member of the door assembly may for or be part of the pre-stressing means. The pre-stressing means further enable providing or enhancing the gas tight closing of the precursor supply chamber. 
     The present invention further relates to a precursor supply cabinet for a precursor supply system in connection with an atomic layer deposition apparatus. The precursor supply cabinet comprises a ventilation inlet connection arranged to provide ventilation gas into the precursor supply cabinet and a ventilation discharge connection arranged to discharge ventilation gas from the precursor supply cabinet. The precursor supply cabinet further comprises one or more gas tight precursor supply chambers inside the precursor supply cabinet. 
     The one or more precursor supply chambers arranged to accommodate a precursor container in connection with an atomic layer deposition apparatus. According to the present invention the precursor supply chamber comprises chamber walls defining a chamber space inside precursor supply chamber. The precursor supply chamber comprises a chamber door assembly arranged to close the precursor supply chamber in gas tight manner, a first heating element provided to the precursor supply chamber and arranged to heat the precursor container inside the chamber space of the precursor supply chamber, and a gas tight precursor connection provided to the chamber walls for supplying precursor from the precursor container outside the precursor supply chamber. 
     The one or more gas tight precursor supply chambers are preferably precursor supply chambers as described above for arranging the one or more gas tight precursor supply chambers in the ventilated precursor supply cabinet. 
     Accordingly, the gas tight precursor supply chambers are arranged into the ventilated inner cabinet space. The gas tight structure of the precursor supply chambers enable preventing the ventilation gas from entering the chamber space of the precursor supply cabinet. Thus, the precursor container may be kept in controlled atmosphere inside the heated precursor supply chamber. 
     An advantage of the invention is that the temperature of the precursor container and thus the precursor may be controlled in detail. The gas tight structure of the precursor supply cabinet enables providing a controlled environment inside the chamber space without subjecting the precursor container to gas flows which may have cooling effect. Further, the precursor supply chamber of the present invention enables providing increasing temperature gradient along the supply path of the precursor inside the precursor supply chamber and out of the precursor supply chamber. Thus, condensation problems may be avoided. 
     Furthermore, if precursor leakage occurs the precursor is not released from the precursor supply chamber but may be contained. The precursor supply chamber makes separate heating elements unnecessary and thus the precursor supply system is more simple and easier to install and maintain. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in detail by means of specific embodiments with reference to the enclosed drawings, in which 
         FIG. 1  shows a schematic view of the precursor supply chamber of one embodiment of the present invention, 
         FIGS. 2 and 3  show schematic side views of one precursor supply chamber according to the present invention; 
         FIGS. 4 and 5  show schematic front views and chamber spaces precursor supply chambers according to the present invention; 
         FIG. 6  shows a schematic side view and chamber space one precursor supply chamber according to the present invention; 
         FIG. 7  shows another schematic front view and chamber space one precursor supply chamber according to the present invention; 
         FIG. 8  shows schematically structure of the chamber walls of one precursor supply chamber according to the present invention; 
         FIG. 9  shows schematically structure of a door of one precursor supply chamber according to the present invention; 
         FIG. 10  shows schematically one embodiment of a precursor supply cabinet according to the present invention; 
         FIG. 11  shows schematically the precursor supply chamber and atomic layer deposition apparatus. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a schematic view of a precursor supply chamber  10  according to one embodiment of the invention. A precursor container or precursor vessel is placed or accommodated inside the precursor supply chamber  10  during operating an atomic layer deposition apparatus. The precursor supply chamber  10  may be further placed or accommodated inside a ventilated precursor supply cabinet. 
     The precursor supply chamber  10  comprises chamber walls  11 ,  13 ,  15 ,  16 ,  18  defining a chamber space or inner chamber space  19  inside the precursor supply chamber  10 , as shown in  FIGS. 1 to 4 . The chamber walls  11 ,  13 ,  15 ,  16 ,  18  further for the chamber body. 
     In the  FIGS. 1 to 10 , the precursor supply chamber comprises a top wall  11  and a bottom wall  13  and side walls  12 ,  15 ,  16 ,  18  extending between the top wall  11  and the bottom wall  13 . 
     The precursor supply chamber  10  further comprises a chamber door assembly  12 ,  30 ,  32  arranged to close the precursor supply chamber  10  or the inner chamber space  19  in gas tight manner. The chamber door assembly  12 ,  30 ,  32  comprises a chamber door  12  arranged in connection of a door opening  21  of the precursor supply chamber  10 . 
     The door opening  21  may be provided on one side walls  12 ,  15 ,  16 ,  18  or top wall  11  or the bottom wall  13  of the precursor supply chamber  10 . In the embodiment, of the  FIGS. 1 to 10  the door opening  21  is provided to one of the side walls, and especially the front wall of the precursor supply chamber  10 . As shown in  FIG. 4 , the door opening  21  is defined by the chamber body or the chamber walls  11 ,  13 ,  15 ,  16 . Especially, the door opening  21  is defined by the side walls  15 ,  16  and the top wall  11  and the bottom wall  13 , or the edges thereof. 
     The wall opening  21  covers the whole front wall of the precursor supply chamber  10 . 
     The chamber door  12  is arranged in connection with the door opening  21  for opening and closing the door opening  21  and also for opening and closing the precursor supply chamber  10  and the inner chamber space  19  thereof. 
     The chamber door  12  comprises door window  14  arranged to provide visual contact to the inner chamber space  19  when the chamber door  12  is in closed position. 
     The chamber door assembly further comprises a door opening and closing mechanism (not shown). The door opening and closing mechanism may comprise hinges or the like enabling opening and closing the chamber door. In the embodiment of the figures, the hinges may be provided to bottom edge of the door  12 . The hinges may also be arranged to some other edge of the chamber door  12 . 
       FIG. 1  shows the precursor supply chamber  10  in closed state and the chamber door assembly  12 ,  30 ,  32  in closed position. Accordingly, the chamber door  12  is in closed position and the precursor supply chamber  10  and the inner chamber space  19  closed in gas tight manner. Thus, the chamber door assembly  12 ,  30 ,  32  arranged to close the door opening  21  of the precursor supply chamber  10  in gas tight manner. 
     Gas tight means in relating to the chamber door assembly, that leakage flow via the chamber door  12  or the door assembly  12 ,  30 ,  32  is less that  5  slm, or preferably less than  3  slm or more preferably less than  1  slm. 
     The chamber door assembly  12 ,  30 ,  32  further comprises a closing mechanism  30 ,  32  arranged to pre-stress the chamber door  12  to the closed position. In the closed position the chamber door  12  is pre-stressed against the chamber body and the chamber walls  11 ,  13 ,  15 ,  16  defining the door opening  21 . 
     In the embodiment of  FIGS. 1 to 3 , the closing mechanism comprises gas struts  32  connected to the chamber body or the side walls  15 ,  16  precursor supply chamber  10  at pivot points  30  and to the chamber door  12 . Accordingly, the gas struts  32  extend between the chamber body or side walls  15 ,  16  and the chamber door  12 . The gas struts  32  are arranged to press the chamber door  12  against the chamber body  11 ,  13 ,  15 ,  16  in the closed position for closing the precursor supply chamber  10  in gas tight manner. 
     In a preferred embodiment, there is a gas strut  32  on both sided of the chamber door  12  and on opposite side walls  15 ,  16 . 
     The closing mechanism is arranged to pull the chamber door  12  towards the closed position when the chamber door  12  is opened, as shown in  FIG. 2 . However, the when the chamber door  12  is opened over a threshold point, for example when the gas struts  32  rotate past the horizontal position over the pivot point  30 , the closing mechanism or the gas struts pull or keep the chamber door in open position as shown in  FIG. 3 . 
     Therefore, when opening the chamber door  12  over the threshold point, the closing mechanism will keep the chamber door  12  open. However, when opening the chamber door  12  less than the threshold point, the closing mechanism will pull the chamber door towards closed position. 
     The gas struts  32  may be replaced by springs of the like. 
     Further, the closing mechanism may comprise also a lock or latch for securing the chamber door to the closed position. The lock or latch may also comprise pre-stressing means, for example an elastic member or spring, for pre-stressing the chamber door  12  to the closed position. In some embodiments, the lock or latch may provide the sole pre-stressing means and the sole closing mechanism. 
     As shown in  FIGS. 2 and 3 , the chamber door assembly further comprises a sealing member  40  arranged to seal the precursor supply chamber  10  when the chamber door is in closed position. The sealing member  40  is provided to the chamber body and to the door opening  21 . Accordingly, the sealing member  40  is provided to the edges of the side walls  15 ,  16 , the top wall and the bottom wall  13  at the door opening  21 . 
     Alternatively or additionally, a sealing element  40  may be provided to the chamber door  12 . 
     The sealing element  40  is arranged between the chamber body and the chamber door  12 , or between the side walls  15 ,  16 , the top wall and the bottom wall  13 , or edges thereof, and the door opening  21  in the closed position of the chamber door  12  for sealing the inner chamber space  19  and the precursor supply chamber  10  in gas tight manner. 
     The precursor supply chamber  10  is comprises a first heating element  61  provided to the precursor supply chamber  10  and arranged to heat a precursor container  80  inside the chamber space  19  of the precursor supply chamber  10 . 
     In the embodiment of  FIG. 4 , the precursor supply chamber  10  comprises a precursor container holder  60  inside the precursor supply chamber  10  for holding the precursor container  80 . The precursor container holder  60  is arranged at bottom of the chamber space  19  of the precursor supply chamber  10 , or to lower part of the chamber space of the precursor supply chamber  10 . Further, the precursor container holder  60  is arranged on bottom wall  13  of the precursor supply chamber  10  or in the vicinity thereof inside the chamber space  19 . The precursor container  80  further placed on the precursor container holder  60 . The precursor container holder  60  is provided as precursor container base in the embodiment of  FIG. 4 . 
     The first heating element  61  is provided to the precursor container holder  60  for heating the precursor container  80  held by or on the precursor container holder  60 . Thus, the first heating element  61  may heat the precursor container  80  on the precursor container holder  60  for heating the precursor inside the precursor container  80 . Thus, the first heating element  61  may be arranged to heat the precursor container  80  from the bottom. 
     The first heating element  61  may be an electrical heating element or a liquid heating element in which heating liquid is circulated, or some other heating element. 
     The first heating element  61  is thus arranged to heat the precursor container holder  60  which in turn heats the precursor container  80 . 
       FIG. 5  shows another embodiment, in which the precursor container holder  60  is formed as a vessel and the fist heating element  61  is provided to the vessel. The precursor container holder  60  may receive the precursor container  80  into the vessel at least partly. Thus, the first heating element  61  may be arranged to heat the precursor container  80  from the bottom and from the side. The precursor container holder  60  of  FIG. 5  may also be formed as a collar which may be arranged around the precursor container  80 . The first heating element  61  may be provided to the collar and arranged to heat the precursor container  80  from the side. 
     In all the above embodiments, the precursor container  80  and the also the first heating element  61  are arranged to the lower part of the chamber space  19 . 
     In an alternative embodiment, the first heating element  61  may be provided to lower part B of the chamber space of the precursor supply chamber  10 . Further, the first heating element  61  may be provided in connection with the bottom wall  13  or on the bottom wall  13  inside the chamber space  19 . 
     In a further embodiment, the first heating element  61  may provided to the bottom wall  13 . Thus, the first heating element  61  may be embedded inside to the bottom wall  13 . 
     In the latter embodiments, the precursor container holder  60  may be omitted, if desired. 
     The precursor container holder  60  may be provided removable such that the may be removed from the precursor supply chamber  10  or it may be placed to the precursor supply chamber  10  together with the precursor container  80 . 
     The precursor supply chamber  10  further comprises a gas tight precursor connection  50  provided to the chamber walls  11 ,  13 ,  15 ,  16 ,  18  for supplying precursor from the precursor container  80  outside the precursor supply chamber  10 . As shown in  FIGS. 2 and 3 , the gas tight precursor connection  50  extends from the chamber walls  11 ,  13 ,  15 ,  16 ,  18  and provides a gas tight lead-through into the chamber space  19  from outside of the precursor supply chamber. Thus, the gas tight precursor connection is open to the inner chamber space  19  and provides gas tight connection into the inner space chamber  19  from outside of the precursor supply chamber  10 . 
     Gas tight in relation to the precursor connection  50  means that leakage flow into the precursor connection from outside is less than 5 slm or between 0 to 5 slm, or less than 3 slm, or more preferably less than 1 slm. The precursor connection  50  is be preferably provided vacuum tight for forming a vacuum tight precursor connection  50 . Vacuum tight means that the leakage flow is less than 0,5 slm or less than 0,1 slm or preferably the leakage is substantially 0 slm. 
     The gas tight precursor connection  50  is used providing gases in and out of the precursor supply chamber  10  and for supplying electricity into the precursor supply chamber  10 , or the like. 
     In the embodiment of the figures, the gas tight precursor connection  50  is provided to back side wall  18  of the precursor supply chamber  10  opposite the door opening  21  and the chamber door  12 . 
     The precursor supply chamber  10  further comprises a precursor supply element  70  arranged to control precursor supply from the precursor container  80  to outside the precursor supply chamber  10  via the gas tight precursor connection  50 , as shown in  FIGS. 4 and 5 . The precursor supply element  70  is provided as a block or the like with gas connections for supplying precursor from the precursor container  80  via the precursor connection  50  outside the precursor supply chamber  10  to an atomic layer deposition reactor. 
     The precursor supply element  70  comprises one or more gas valves  73 ,  74 ,  75  arranged to control precursor supply from the precursor container  80  outside the precursor supply chamber  10  via the gas tight precursor connection  50 . 
     The precursor supply element  70  may comprise for example a carrier gas valve  73 , a precursor valve  74  and a supply valve  75 , as shown in  FIGS. 4 and 5 . Accordingly, the valves  73 ,  74 ,  75  may be attached fixedly or detachably to the precursor supply element  70 . 
     The precursor supply element  70  is arranged to upper part of the chamber space  19  of the precursor supply chamber. 
     The precursor supply element  70  is arranged above the precursor container holder  60  inside the precursor supply chamber  10 , when the precursor supply chamber  10  comprises the precursor container holder  60 . 
     Further, in one embodiment the precursor supply element  70  is arranged in connection with the top wall  11 . The precursor supply element  70  may be attached to the top wall  11  inside the inner chamber space  19  or it may be attached to the side wall  15 ,  16 ,  18  in vicinity of the top wall  11 . 
     In one embodiment, the precursor supply element  70  is attached removable to the precursor supply chamber  10  and inside the inner chamber space  19 . Thus, the precursor supply element  70  may be provided as removable element to the precursor supply chamber  10 . Thus, all the gas valves  73 ,  74 ,  75  may be removed simultaneously by removing the precursor supply element  70 . This makes maintenance work simpler. 
     In an alternative embodiment, the precursor supply element  70  may be omitted and the gas valves may be provided to the precursor supply chamber  10  as separate parts. The one or more separate gas valves  73 ,  74 ,  75  are arranged to control precursor supply from the precursor container  80  outside the precursor supply chamber  10  via the gas tight precursor connection  50 . 
     The precursor supply chamber  10  further comprises a second heating element  71  provided to the upper part of the chamber space of the precursor supply chamber  10 . Furthermore, the second heating element  71  is provided above the first heating element  61  inside the inner chamber space  19  of the precursor supply chamber  10 . 
     Further, preferably the second heating element  71  is provided above the precursor container holder  60  in the precursor supply chamber  10 , as shown in  FIGS. 4, 5, 6 and 7 . 
     As shown in the  FIGS. 4 to 7 , the second heating element  71  is provided to the precursor supply element  70 . Therefore, the second heating element  71  is arranged to heat the precursor supply element  70  and further the precursor gas supplied from the precursor container  80  to the precursor supply element  70 . The second heating element also keeps the gas valves  73 ,  74 ,  75 , as gas conduits in the precursor supply element  70 , at the desired temperature as they are provided to the same block. Thus, the temperature of the precursor may be controlled in detail inside the inner chamber space  19  when the precursor is supplied from the precursor container  80  out of the precursor supply chamber  10 . 
     The second heating element  71  may be an electrical heating element or liquid heating element in which heated liquid is circulated, or some other heating element provided inside the chamber space  19 . 
     The second heating element  71  is thus arranged to heat the gas valves and gas conduits in connection with the gas valves  73 ,  74 ,  75  for heating the precursor. 
     In an alternative embodiment, the second heating element  71  may be provided to upper part of the chamber space  19  of the precursor supply chamber  10 . Further, the second heating element  71  may be provided in connection with the top wall  11  or on the top wall  11  inside the chamber space  19 . 
     In a further embodiment, the second heating element  71  may be provided to the top wall  11 . Thus, the second heating element  71  may be embedded inside to the top wall  11 . 
     In the latter embodiments, the precursor supply element  70  may be omitted, if desired, and the gas valves  73 ,  74 ,  75  may be separate gas valves. 
     In all the above embodiments, the precursor supply element  70  and the also the second heating element  71  are arranged to the upper part of the chamber space  19 . 
     As shown in  FIG. 6 , in this embodiment the precursor supply chamber  10  comprises a third heating element  52  provided to the gas tight precursor connection  50 . The third heating element  52  may be provided inside the gas tight precursor connection  50  for heating gas conduits  76 ,  84  and thus the gases such as precursor gas in precursor conduit  76 . 
     The third heating element  52  may be an electrical heating element or liquid heating element in which heated liquid is circulated, or some other heating element provided inside the gas tight precursor connection  50 . 
     The precursor container  80  is a vessel and may comprise container valve  82  for opening and closing the precursor container  80 , as shown in  FIGS. 4, 5 and 6 . The precursor container  80  is connected to a precursor valve  74  with the container conduit  82  extending between the precursor container  80  and the precursor valve  74 . 
     The precursor supply chamber  10  may further comprise carried gas valve  73 . A carrier gas conduit  84  is connected to the carrier gas valve  73 . The carrier gas conduit  84  extends into the chamber space  19  and to the carrier gas valve  73  from the precursor connection  50 . Thus, carrier gas is brought to the precursor supply chamber  10  from outside of the precursor supply chamber  10  via the precursor connection  50 . 
     The precursor supply chamber  10  further comprises a precursor supply valve  75  arranged to supply the precursor out of the precursor supply chamber  10 . There is precursor supply conduit  76  extending from the precursor supply valve  75  out of the precursor supply chamber  10  via the precursor connection  50 . 
     The carrier gas conduit  84  and the container conduit  82  are connected to the precursor supply conduit  76  in a connection point and the precursor supply valve  75  is provided to the precursor supply conduit  76  downstream of the connection point. Further, the carrier gas valve  73  is provided to the carrier gas conduit  84  upstream of the connection point. The precursor valve  74  is provided to the container conduit  82  upstream of the connection point. 
     The carrier gas valve  73 , precursor valve  74  and the precursor supply valve  75  are provided to the precursor supply element  70 . However, in other embodiments they may also be provided as separate valves. 
     A first power line  63  is connected to the first heating element  61  and a second power line  77  is connected to the second heating element  71 . The first and second power line  63 ,  77  extend to the precursor supply chamber  10  via the precursor connection  50 . The first and second power line  63 ,  77  are arranged to provide electricity to the first and second electrical heating elements  61 ,  71 , respectively. It should be noted, that the first and second power line  63 ,  77  may also be provided as liquid lines when the first and second heating element  61 ,  71  are provided as liquid heating elements. 
     Furthermore, it should be noted that the present invention is not restricted to any particular configuration gas conduits, gas valves or power lines, but they may vary within scope of the claims. 
     As shown in  FIG. 6 , the precursor supply chamber  10  comprises a first temperature sensor  62  arranged in connection with the first heating element  61 . 
     The first temperature sensor  62  may be provided to the precursor container holder  60  for measuring the temperature of the precursor container holder  60  and thus the precursor container  80  and also the precursor. 
     Similarly, as shown in  FIG. 6 , the precursor supply chamber  10  comprises a second temperature sensor  72  arranged in connection with the second heating element  71 . 
     The second temperature sensor  72  may be provided to the precursor supply element  70  for measuring the temperature of the precursor supply element  70  and thus the precursor or the valves during supply of the precursor. 
     Further, as shown in  FIG. 6 , the precursor supply chamber  10  comprises a third temperature sensor  78  arranged in connection with the precursor connection  50 . 
     The third temperature sensor  78  may be provided to the precursor connection for measuring the temperature of the precursor connection  50  the precursor supply conduit  76  in the precursor connection  50  and the temperature precursor. The third heating element  52  is provided in connection with the precursor supply conduit  76  for heating the precursor supply conduit  76  in the precursor connection  50 . 
     According to the above mentioned, the first, second and third hating elements may be utilized such that an increasing temperature gradient is provided from the precursor container  80  to the precursor connection  50 . Thus, the first heating element  61  may be arranged to operate in first temperature and the second heating element  71  at a second temperature which is higher than the first temperature. 
     Further, the second heating element  71  may be arranged to operate in second temperature and the third heating element  52  at a third temperature which is higher than the second temperature. Thus, the temperature of the precursor may increase from the precursor container  80  to the precursor connection  50 . Therefore, condensation of the precursor may be avoided. 
     The temperatures of the first, second and third heating elements  61 ,  71 ,  52  are controlled with a control unit (not shown) by utilizing the temperature sensors  62 ,  72 ,  78 . 
       FIG. 7  shows schematically the arrangement of the precursor container holder  60 , the first heating element  61 , the precursor supply element  70  and the second heating element  71 . 
     The precursor supply chamber  10  and the inner chamber space  19  has a lower part B and an upper part A in the vertical direction. The upper part A extends from the top wall  11  downwards and the lower part B extends from the bottom wall  13  upwards, as shown in  FIG. 7 . 
     The first heating element  61  is provided to lower part B of the chamber space  19  of the precursor supply chamber  10 . The second heating element  71  is provided to the upper part A of the chamber space of the precursor supply chamber  10 . 
     The precursor container holder  60  is arranged to lower part B of the chamber space  19  of the precursor supply chamber  10 . 
     The precursor container holder  60  provided with the first heating element  61  is arranged to lower part B of the chamber space  19  of the precursor supply chamber  10 . 
     The precursor supply element  70  is arranged to upper part A of the chamber space of the precursor supply chamber  10 . 
     The precursor supply element  70  provided with the second heating element is arranged to upper part A of the chamber space of the precursor supply chamber  10 . 
     Thus, the precursor supply element  70  is arranged above the precursor container holder  60  inside the precursor supply chamber  10 . Further, the second heating element  71  is provided above the first heating element  61  in the precursor supply chamber. 
       FIG. 8  shows the structure of the chamber walls  11 ,  13 ,  15 ,  16 ,  18  according to one embodiment. The chamber walls  11 ,  13 ,  15 ,  16 ,  18  are made of metal such that the metal chamber walls  11 ,  13 ,  15 ,  16 ,  18  define the chamber space  19  of the precursor supply chamber  10 . 
     As shown in  FIG. 8 , the chamber walls  11 ,  13 ,  15 ,  16 ,  18  comprise a metal inner wall layer  91  defining the chamber space  19  of the precursor supply chamber. Further, the chamber walls  11 ,  13 ,  15 ,  16 ,  18  comprise the metal inner wall layer  91  and a metal outer wall layer  90  the metal inner wall layer  91  defining the chamber space  19  of the precursor supply chamber  10 . 
     The metal may be stainless steel, aluminium or the like metal. Instead of metal also some other material may be used. 
     Further, the chamber walls  11 ,  13 ,  15 ,  16 ,  18  are provided with thermal insulation  92 . The thermal insulation layer  92  is arranged between the metal inner wall layer  91  and the metal outer wall layer  90 . Accordingly, the thermal insulation  92  is encapsulated inside the chamber walls  11 ,  13 ,  15 ,  16 ,  18  between the metal surface layers. The thermal insulation layer prevents thermal energy from escaping the precursor supply chamber  10 . 
       FIG. 9  shows the door  12  of the precursor supply chamber  10 . The door  12  has a similar structure as the chamber walls  11 ,  13 ,  15 ,  16 ,  18 . The door  12  is made of metal and has a metal inner door layer  94  towards the chamber space  19  of the precursor supply chamber  10 . 
     As shown in  FIG. 9 , the door  12  comprises the metal inner door layer  94  defining the chamber space  19  of the precursor supply chamber  10 . Further, the door  12  comprise the metal inner door layer  94  and a metal outer door layer  93  the metal inner door layer  94  defining the chamber space  19  of the precursor supply chamber  10 . 
     The metal may be stainless steel, aluminium or the like metal. Instead of metal also some other material may be used. 
     Further, the door  12  is provided with thermal insulation  95 . The thermal insulation layer  95  is arranged between the metal inner door layer  94  and the metal outer door layer  93 . Accordingly, the thermal insulation  95  is encapsulated inside the door  12  between the metal surface layers. The thermal insulation layer prevents thermal energy from escaping the precursor supply chamber  10  via the door  12 . 
     The precursor supply chamber or chambers  10  are arranged into a precursor supply cabinet  100  of a precursor supply system in connection with an atomic layer deposition apparatus, as shown in  FIG. 10 . The precursor supply cabinet  100  comprises cabinet walls defining inner cabinet space. The precursor supply cabinet  100  comprises one or more ventilation openings  110  arranged to provide ventilation gas into inner cabinet space of the precursor supply cabinet  100  from outside the precursor cabinet  100 . The precursor supply cabinet  100  further comprises a ventilation discharge connection  120 ,  122  arranged to discharge ventilation gas from the inner cabinet space of the precursor supply cabinet  100 . 
     The ventilation discharge connection comprises a ventilation outlet  120  open to the inner cabinet space. A suction device of under pressure device  122  is connected to the ventilation outlet  120  from discharging the ventilation gas from the inner cabinet space and also from outside the inner cabinet space into the inner cabinet space via the one or more ventilation openings  110 . 
     Accordingly, the precursor supply cabinet  100  provides a ventilated inner cabinet space. 
     The precursor supply cabinet  100  further comprises one or more gas tight precursor supply chambers  10  arranged inside the precursor supply cabinet  100  into the inner cabinet space. The one or more gas tight precursor supply chambers  10  are precursor supply chambers as disclosed above for arranging the one or more gas tight precursor supply chambers  10  in the ventilated precursor supply cabinet  100 . 
     In one embodiment, the one or more precursor supply chambers  10  are arranged in the inner cabinet space spaced apart from each other. 
     In one embodiment, the one or more precursor supply chambers  10  are arranged in the inner cabinet space spaced apart from cabinet walls. 
     In another embodiment, the one or more precursor supply chambers  10  are arranged in the inner cabinet space spaced apart from each other and from the cabinet walls. 
     The precursor supply cabinet  100  comprise cabinet doors  105  aligned and/or opposite the precursor supply chambers  10  in the precursor supply cabinet  100 . 
       FIG. 11  shows schematically, that the precursor supply chambers  10  are connected to an atomic layer deposition reactor or apparatus  200 . The atomic layer deposition apparatus  200  comprises a vacuum chamber  202  and a reaction chamber  204  inside the vacuum chamber  202 . The precursor is fed from the precursor container  80  inside the precursor supply chamber  10  to the reaction chamber  204  in which a substrate is processed with the precursor. The precursor supply chambers  10  may be arranged inside the precursor supply cabinet  100 , or alternatively the precursor supply cabinet  100  may be omitted. 
     The invention has been described above with reference to the examples shown in the figures. However, the invention is in no way restricted to the above examples but may vary within the scope of the claims.