Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
  • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
  • H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
  • H01L21/02252—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by plasma treatment, e.g. plasma oxidation of the substrate
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/50—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/50—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges
  • C23C16/505—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges using radio frequency discharges
  • C23C16/509—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges using radio frequency discharges using internal electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
  • H01J37/32192—Microwave generated discharge
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
  • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
  • H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
  • H01L21/0223—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate
  • H01L21/02233—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer
  • H01L21/02236—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor
  • H01L21/02238—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor silicon in uncombined form, i.e. pure silicon
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
  • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
  • H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
  • H01L21/02247—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by nitridation, e.g. nitridation of the substrate
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
  • H01L21/67005—Apparatus not specifically provided for elsewhere
  • H01L21/67011—Apparatus for manufacture or treatment
  • H01L21/67098—Apparatus for thermal treatment
  • H01L21/67115—Apparatus for thermal treatment mainly by radiation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
  • H01L21/677—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for conveying, e.g. between different workstations
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
  • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
  • H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
  • H01L21/02123—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon
  • H01L21/02164—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material being a silicon oxide, e.g. SiO2
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
  • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
  • H01L21/0226—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
  • H01L21/02263—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase
  • H01L21/02271—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition
  • H01L21/02274—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition in the presence of a plasma [PECVD]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
  • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
  • H01L21/0226—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
  • H01L21/02263—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase
  • H01L21/02271—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition
  • H01L21/0228—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD

Definitions

• the present invention relates to a method and an apparatus for forming a dielectric layer on a substrate, in particular on a semiconductor substrate.
• dielectric layers are formed on a substrate or another layer.
• An example of such a method is the formation of thermal oxide layers on semiconductor substrates in so-called ovens or rapid heating systems (RTP systems).
• RTP systems rapid heating systems
• a disadvantage of such a thermal oxidation can be, inter alia, the temperatures used in which the oxidation is carried out, since these can affect the underlying structures. Therefore, such systems are always striving to reduce the thermal budget of the treatment, but only partially succeed.
• a plasma treatment of substrates for forming dielectric layers is also known.
• the US patent describes 7,381,595 B2 discloses low temperature plasma oxidation of a silicon semiconductor using a high density plasma.
• the plasma source hereinafter referred to collectively as a plasma electrode is formed by two plate-shaped opposing electrodes. The substrates are received between the two plate-shaped opposing electrodes and themselves form part of one electrode.
• the temperatures used in plasma oxidation significantly reduce the thermal budget over thermal oxidation, and can thereby improve the associated disadvantages.
• a similar plasma electrode which is formed from two opposing plate-shaped electrodes, and in which a substrate to be treated is arranged between the electrodes, results from US Pat. No. 6,037,017 A. In this plasma electrode, the distance between the electrodes is different Process parameters adjustable. Further plasma electrodes of this type are known from US2007 / 0026540 A1, US Pat. No. 5,492,735 and US Pat. No. 5,281,557.
• WO 2010/01 5385 A describes an alternative rod-shaped microwave plasma electrode, in which an inner conductor is completely surrounded by an outer conductor in a first partial region. Adjacent to this sub-area is followed by a sub-area, in which the outer conductor provides an opening which widens to a free end. In the area of the widening opening, microwave power is decoupled to produce a plasma.
• Another rod-shaped plasma electrode with inner conductor, outer conductor and a coupling-out structure is known, for example, from DE 197 22 272.
• Such rod-shaped plasma electrodes may be disposed opposite to a substrate to be treated, and the substrate is not disposed between the plasma-generating electrodes. With Such plasma electrodes can achieve improved processing results, but still can not be sufficiently good. In particular, electrical properties of layers formed using these plasma electrodes may still be insufficient.
• a plasma is generated from a process gas between the substrate and a plasma electrode opposite the substrate, resulting in an at least partial chemical reaction of substrate and process gas and / or at least partial deposition of Process gas components for forming the dielectric layer on the substrate results.
• the distance between the plasma electrode and the substrate is changed, whereby the formation of a homogeneous dielectric layer can be promoted.
• plasma electrode refers to a unit of two electrodes rather than a single electrode. The change in the distance during the formation of the dielectric layer makes it possible to improve the electrical parameters of the dielectric layer.
• the underlying growth mechanism can be influenced, whereby the formation of the dielectric layer and its electrical properties can be improved.
• the growth mechanism is based on the effect of radical components of the plasma gas. Due to the large distance, a recombination of the electron density with the ion density takes place and only the radicals are retained and only oxidize the surface with a limited thickness.
• anodic effect prevails directly at the substrate surface due to the large electron concentration.
• such a change in the growth mechanism affects the electrical parameters of the growing dielectric layer and, in particular, the interface properties to the underlying substrate.
• the plasma is preferably at least partially generated by rod-shaped microwave plasma electrodes with inner and outer conductors having a fixed distance from each other.
• a plasma electrode as described in WO 2010 015385 A, which is the subject of the present invention with regard to the structure of the plasma electrode.
• the inner conductor and the outer conductor have an arbitrary but fixed distance from each other, and the coupling-out structure causes a microwave to be radiated and a plasma to be ignited.
• the substrate to be treated does not lie between the electrodes of the plasma electrode. There must be no low pressure between the electrodes, as is the case with plate-shaped electrodes, which form a plasma between them.
• the rod-shaped plasma electrodes can also lie outside the actual process area and, for example, be separated from a generated plasma by means of cladding tubes that are substantially transparent to microwave radiation.
• the rod-shaped plasma electrode may be surrounded by an electron tunnel in which different species with different charge states are located. This electron tunnel sees the different species for a reaction with / deposition on the sub- strat and also shields the substrate from microwave radiation so that it can not get onto the substrate.
• a method of forming a dielectric layer by oxidizing and / or nitriding a substrate or deposition in which a plasma of a process gas is generated by at least one plasma electrode adjacent to the substrate, the substrate being floating and not between electrodes the at least one plasma electrode is located, and wherein a correlation between the substrate and the plasma during the formation is changed such that at an instant of formation of the layer anodic reaction prevails and at another time a radical reaction.
• the change in the interactions can advantageously take place via a change in the distance between the plasma electrode and the substrate.
• a grid of electrically conductive material may be provided between the at least one plasma electrode and the substrate whose electrical bias is changed.
• the distance between the plasma electrode and the substrate is set as a function of the thickness of the already grown and / or deposited layer and in particular reduced with increasing layer thickness.
• z. B. first be achieved by a radical components of the plasma gas driven layer structure without strong electric field and by random diffusion of the reaction components. Subsequent reduction of the distance shifts the predominant effect to an anodic effect where the electric field should preferably be perpendicular to the substrate surface. This results in a self-healing effect in the growth of the dielectric layer and the layer thickness becomes more homogeneous or the atomic interface flatter. hereby the electrical parameters of the dielectric layer are positively influenced.
• the energy supplied to the plasma electrode, the pressure and / or the composition of the process gas and / or the temperature of the substrate, which is heated to a predetermined temperature via at least one heat source independent of the plasma are set as a function of the distance between the plasma electrode and the substrate.
• the plasma can be controlled and adapted to the growth mechanism, and on the other hand, the layer formation can be influenced by the temperature of the substrate.
• the substrate is a semiconductor substrate, and in particular a silicon substrate, which is often used in semiconductor technology because of its comparatively low cost.
• the substrate can also be, for example, a large panel for the solar industry, a coated glass plate, or any other substrate.
• the grown and / or deposited layer is preferably an oxide, an oxynitride, a nitride or other material with a high dielectric constant of k> 3.9.
• the plasma is generated by microwave radiation.
• the plasma is generated with RF radiation.
• the plasma is preferably operated pulsed.
• the growth and / or deposition rate is preferably controlled such that the layer structure has a substantially constant rate of less than 0.5 nm / s, in particular less than 0.1 nm / s and preferably takes place at 0.01 to 0.05 nm / s.
• essentially constant rate is considered a rate with a maximum deviation of ⁇ 10% with respect to an average value.
• a process chamber having at least one process gas inlet and at least one substrate holder is provided, which defines a receiving area for receiving the substrate, and at least one plasma electrode for generating a plasma in a holding area for the substrate.
• the plasma electrode is formed from two lying at different potential electrodes, which are outside the process chamber, and thus can be isolated from the process gas, if desired. In such plasma electrodes, the plasma is not generated primarily in a region between the electrodes but adjacent to / surrounding them.
• means are provided for varying a distance between the at least one plasma electrode and the receiving area for the substrate during the formation of the dielectric layer in order to be able to provide a corresponding change in distance with the above-mentioned advantages during the layer growth. It is essential that this change not be made once and maintained for a subsequent process, but that the means are specifically able to provide a corresponding change during the formation of the dielectric layer.
• an apparatus for forming a dielectric layer on a substrate by means of oxidizing and / or nitriding the substrate is provided.
• the device has a process chamber with at least one process gas inlet and at least one substrate holder, which has a receiving region for holding the substrate in a potential-free state. Furthermore, the device provides at least one plasma electrode having two electrodes for generating a plasma adjacent to or in a holding region for the substrate, wherein the holding region for the substrate is not between the electrodes and means for changing an interaction between a substrate and a plasma during formation of the dielectric layer such that anodic reaction prevails at a time of formation of the layer and at a later time a radical reaction.
• This can be achieved, for example, by setting the distance between the plasma electrode and the substrate and / or a grid between the plasma electrode and the substrate, which can be subjected to different electrical bias voltages, or by varying the process gas pressure by which the plasma expansion is varied.
• the at least one substrate holder has at least one conveying unit for transporting the substrate along a transport path through the process chamber in order to be able to provide a continuous process during the passage through the process chamber.
• a plurality of plasma electrodes are preferably provided, which are arranged at least partially at different distances to the transport path for the substrate, whereby the corresponding distance adjustment between plasma electrode and substrate is automatically provided during the process by the transport of the substrate along the transport path.
• at least one plasma electrode arranged in front in the transport direction of the substrate is arranged at a greater distance from the transport path for the substrate, than a plasma electrode lying behind in the transport direction of the substrate.
• a reduction in the distance between the plasma electrode and the substrate is automatically provided during the passage and the correlation between plasma and substrate is changed.
• a plurality of plasma electrodes may be provided in a plane lying substantially parallel to the transport path, in order to provide a uniform correlation and thus a constant growth mechanism.
• a control unit for controlling the distance between the at least one plasma electrode and the receiving area for the substrate during the formation of the dielectric layer and the energy supplied to the plasma electrode and / or the pressure or the composition of the process gas and / or the temperature of the substrate , which is heated to at least one plasma-independent heating unit to a predetermined temperature provided.
• This makes it possible to adjust the plasma properties and possibly the temperature of the substrate, which can each influence the growth mechanism.
• the plasma electrode has a microwave applicator.
• the plasma electrode has an RF electrode.
• at least one grid is provided between the at least one plasma electrode and the receiving area for the substrate. It may be advantageous to be able to change the distance between the grid and the plasma electrode or grid and substrate optionally independent of the distance between the plasma electrode and the substrate.
• At least one heating unit is provided for heating the substrate within the process chamber, wherein the at least one heating unit is arranged such that the receiving area for the substrate lies between the at least one plasma electrode and the at least one heating unit.
• This makes it possible to heat the substrate independently of the plasma, in particular such that the plasma electrode does not interfere with heating.
• means are provided for changing the distance between the receiving area for the substrate and the at least one heating unit.
• Fig. 1 is a schematic sectional view through an apparatus for forming a dielectric layer according to a first embodiment of the invention
• FIG. 2 shows a schematic sectional view through an apparatus for forming a dielectric layer according to a second embodiment of the invention:
• 3 is a Weibull diagram showing the defect density versus the surface charge density of differently formed dielectric layers.
• 5a and 5b are schematic representations showing different correlations between a plasma and a substrate as a function of the distance between the plasma electrode and the substrate;
• Figures 6a and 6b are schematic representations illustrating different correlations between a plasma and a substrate in response to an electrical bias of a grid interposed between the plasma electrode and the substrate.
• FIG. 1 shows a schematic sectional view through a device 1 for forming dielectric layers on a substrate 2.
• the device 1 has a vacuum housing 3, which is only indicated in outline, and which defines a process chamber 4.
• the device 1 further comprises a transport mechanism 6, a plasma unit 8, and a heating unit 10.
• a cooling unit may be provided which forms a temperature control unit together with the heating unit.
• the substrate may be at least partially surrounded by a protective element, not shown, which is in the same plane as the substrate in order to avoid edge effects in the coating and to virtually enlarge the physical surface of the substrate.
• the protective element should preferably have the same or at least similar physical property as the substrate.
• the vacuum housing 3 has suitable, not shown locks for loading and unloading of the substrates 2 in the process chamber 4.
• the process chamber 4 is limited, inter alia, by an upper wall 12 and a lower wall 14.
• the top wall 12, for example, is constructed of aluminum and treated so as to avoid metal contamination or particles in the process chamber.
• the top wall 12 has an oblique portion which is angled with respect to the bottom wall 14 and a portion substantially parallel to the bottom wall, as can be clearly seen in FIG.
• the inclined wall portion is arranged so that the process chamber from left to right - as will be explained in more detail below from an input end to an output end - tapers.
• the straight area then joins this oblique area.
• the lower wall 14 extends in a straight line and is constructed, for example, of quartz glass in order to be able to conduct electromagnetic radiation, as will be explained in more detail below.
• a vacuum pump 16 is provided, via which the process chamber 4 can be pumped out.
• the pump can also be provided at a different location and there may be several be provided.
• a pyrometer 18 is provided for a temperature measurement of the substrate 2. Instead of a pyrometer but also another temperature measuring device may be provided at another location of the process chamber or directly on the substrate 2, for example, also from above the temperature of the substrate measure 2. It can also be provided more temperature measuring devices.
• the process chamber 4 also has at least one gas supply, not shown, via which a process gas can be introduced into the process chamber 4.
• the transport unit 6 consists essentially of an endless conveyor belt 20, which is circumferentially guided over a plurality of deflection and / or transport rollers 22.
• the normal direction of rotation for a treatment of the substrate 2 is in the clockwise direction, but it is also possible to circulate the conveyor belt in a counterclockwise direction.
• an overhead Transporttrum the conveyor belt 20 is arranged such that it extends straight through the process chamber 4 therethrough.
• the return of the conveyor belt 20 takes place outside the process chamber 4 in order to be able to carry out, for example, cooling and / or cleaning processes on the conveyor belt 20 there.
• the conveyor belt 20 consists of a material substantially transparent to electromagnetic radiation.
• the conveyor belt 20 should be arranged as completely as possible within the vacuum range, but may also be at least partially outside the vacuum range in a suitable arrangement.
• the transport unit 6, for example, also have a different transport mechanism, such as transport rollers or a magnetic or air cushion guide.
• the transport unit 6 can optionally be moved up and down as a whole, as indicated by the double arrow A. This makes it possible, the transport unit 6 and in particular its Transporttrum closer to the obe- ren wall 12 or the lower wall 14 to place, as will be explained in more detail below.
• the plasma unit 8 is further arranged.
• the plasma unit 8 consists of a plurality of plasma electrodes 24.
• the plasma electrodes are preferably designed as rod-shaped microwave applicators having an inner conductor and an outer conductor.
• the outer conductor is designed such that it enables the microwaves to be coupled out of the intermediate region between the inner and outer conductors in order to form a plasma outside this region, which surrounds the rod-shaped plasma electrode in the radial direction, for example.
• the microwave applicators are preferably constructed in particular in such a way that microwave radiation can exit substantially vertically downwards, that is to say in the direction of the lower wall 14.
• one or more plasma ignition devices may be provided.
• the plasma electrodes may also be of the HF type; in particular, it is also conceivable to arrange plasma electrodes 24 of different types within the process chamber 4.
• RF plasma electrodes may be provided in one subarea and microwave plasma electrodes may be provided in another area.
• the respective plasma electrodes have in common that the substrates are not located between the conductors / electrodes of the plasma electrode.
• the structure of the plasma electrodes can be chosen so that the burning plasma is limited in its extent and does not come into contact with walls of the process chamber.
• the rod-shaped plasma electrodes 24 each extend perpendicular to the plane of the drawing across the process chamber 4. From left to right, ie from an input end to an output end of the process chamber 4, the plasma electrodes are equally spaced following the contour of the top wall 12. As a result, the plasma electrode 24 closest to the input end of the process chamber 4 is furthest away from the transport strand of the conveyor belt 20.
• the plasma electrodes 24 are then arranged closer and closer to the conveyor belt 20, and from the middle they are then arranged in each case at the same distance from the conveyor belt. As a result, the distance between the substrate 2 and the plasma electrodes 24 lying directly above it changes during the movement through the process chamber 24.
• the heating unit 10 consists of a multiplicity of radiation sources 30 which emit electromagnetic radiation for heating the substrate 2 in the direction of the process chamber 4.
• halogen and / or arc lamps 31 can be used, as they are commonly used, for example, in high-speed heating systems.
• the lamps 31 may optionally be accommodated in quartz tubes 32 in order to provide insulation against process gases and / or underpressure conditions in the region of the process chamber 4. This may be particularly useful if the radiation sources are received directly within the process chamber 4. That is not on the lower wall 14 are separated from this.
• heating lamps can also be arranged above the transport unit 6, for example also between the plasma electrodes 24.
• Fig. 2 shows a schematic sectional view of an alternative device 1 for applying dielectric layers on a substrate 2 according to an alternative embodiment.
• the device 1 again has a housing, which is shown only very schematically at 3. This housing is in turn filled out as a vacuum housing, and can be pumped via a vacuum unit, no longer shown, to vacuum pressure.
• a process chamber 4 is defined.
• the device 1 further has a substrate support unit 6, a plasma unit 8 and a heating unit 10.
• the support unit 6 has a substrate support 40, which is rotatably supported by a shaft 42 within the process chamber 4, as shown by the arrow B.
• the shaft 42 is connected for this purpose with a rotary unit, not shown.
• the shaft 42 and thus the pad 40 is movable up and down, as shown by the double arrow C.
• the support level of the support 40 within the process chamber 4 can be adjusted upwards or downwards, as will be explained in more detail below.
• the plasma unit 8 again consists of a plurality of plasma electrodes 24, which may be of the same type as described above.
• the plasma electrodes may be slidable up and down within the process chamber 4 via respective guides 46, as indicated by the double arrow D.
• the up and down mobility of the support unit 6 could be omitted, but it can also be provided in addition.
• this makes it possible to provide, in combination with the rotation of a substrate 2 by the support unit 6, for example, in an edge region of the substrates 2 larger or smaller distances compared to a central region thereof.
• a protective device can be provided which surrounds substrate 2 at least partially in its plane in order to avoid edge effects.
• the protective device may be arranged with respect to the rotation static or rotatable.
• the heating unit 10 in turn consists of a plurality of radiation sources 30, which may be arranged parallel or perpendicular to the plasma electrodes 24.
• the radiation sources each have a lamp, such as an arc or halogen lamp, which is surrounded by a quartz tube 32.
• the radiation of the radiation sources 30 is able to heat the substrate 2 directly when the support 40 for the radiation of the radiation source 30 is substantially transparent.
• the support 40 could be constructed, for example, of quartz.
• the device 1 preferably has at least one temperature measuring unit in order to determine the temperature of the substrate 2.
• the determined temperature can be forwarded to a control unit, not shown, which can then regulate the heating unit 10 according to a temperature specification accordingly to obtain a predetermined temperature of the substrate, as is known in the art.
• the substrate 2 is each a silicon semiconductor wafer.
• a silicon oxide layer is to be formed as a dielectric layer during the process described below.
• a suitable process gas for example, pure oxygen or an oxygen-hydrogen mixture is introduced into the process chamber 4, in which there is a negative pressure.
• a plasma of the process gas is generated in the region of the plasma electrodes 24.
• the substrate 2 is guided via the conveyor belt 20 from left to right through the process chamber, while a corresponding plasma burns below the respective plasma electrodes 24.
• the left-lying plasma electrodes 24, that is to say inlet plasma electrodes 24, are further away from the substrate 2 than the plasma electrodes 24 on the right, ie in the exit region of the process chamber 4, as it is conveyed through the process chamber.
• the distance of the plasma electrodes from the substrate surface changes. This results in different growth mechanisms for layer growth. These are caused by different interactions between plasma and substrate, as will be explained in more detail below with reference to FIG. 5.
• 5a and 5b show different correlations between a plasma and a substrate as a function of a distance between a rod-shaped plasma electrode 300 and a substrate 320.
• the rod-shaped plasma electrode 300 is of the type described in WO 2010/015385 A and the one Inner conductor 304 and an outer conductor 306 have.
• the outer conductor 306 does not completely surround the inner conductor 304. Rather, the outer conductor 306 sees an opening that enlarges to a free end thereof that faces the substrate 320.
• 5a and 5b each show a cross section in this coupling-out region of the microwave electrode 300.
• the electrode 300 is surrounded in each case by a cladding tube 308, which is substantially transparent to microwave radiation, such as, for example, a quartz tube. With a corresponding activation of the plasma electrode 300, a plasma surrounding the cladding tube 308 is generated, which consists of electrons 31 0, radicals 312 and ions 314.
• Fig. 5a and 5b show respectively a portion of a substrate 320, which for example consists of a Si base substrate 322 having a dielectric layer 324 of, e.g., SiO x N y, where x and y can arbitrarily variie- ren.
• a substrate 320 which for example consists of a Si base substrate 322 having a dielectric layer 324 of, e.g., SiO x N y, where x and y can arbitrarily variie- ren.
• positive Si ions are indicated.
• the plasma electrode is arranged at a distance Di from the surface of the substrate 320.
• the plasma in this arrangement is arranged with respect to the substrate such that a substantially uniform distribution of the electrons 310, radicals 312 and ions 314 present in the plasma occur adjacent to the surface of the substrate.
• anodic oxidation / nitridation is self-aligning and self-healing, so that any geometric shapes and layer structures (3D structures) can be homogeneously oxidized / nitrided or any other dielectric layers can be deposited.
• the self-healing effects of anodic oxidation / nitridation lead to a homogeneous breakthrough resistance of the grown layer, since the oxide / nitride grows until the electrical potential has decayed over the layer thickness.
• the E field is constant given by the electron density at the surface of the dielectric layer 324.
• the plasma electrode is arranged at a greater distance D 2 from the surface of the substrate 320.
• the plasma in this arrangement is arranged with respect to the substrate such that essentially only the radicals 312 occur adjacent to the surface of the substrate. This results in a process gas-dependent radical oxidation / nitridation of the substrate surface. Compared to the Deal Groove model, it represents an extension of the growth model for plasma enhanced and thus enhanced growth processes.
• the growth process is limited by the reaction rate, but due to the low substrate temperature of preferably ⁇ 450 ° C only up to about 2 nm and not to 5 or 10 nm as in high temperature processes at> 800 ° C.
• the radicals 312 on the surface of the dielectric layer 324 impart a large chemical affinity. There is little diffusion of the oxidizing species through the dielectric layer to the interface or from the substrate self-interstitial atom (charged or uncharged) to the surface of the dielectric layer to react with the adsorbed radicals.
• the growth process is diffusion rate limited, as in thermal processes, but because of the low substrate temperature, an additional driving force is needed to accelerate the diffusion of the various species. In anodic oxidation / nitridation, such additional driving force is generated by a large electrical field caused by the electrons 310 on the surface of the dielectric layer 324. Therefore, this process can grow in a relatively short time up to 1 5 nm thick dielectric layers.
• both oxidizing species driven by electrical potential, diffuse to the interface between base substrate 322 and dielectric layer 324 and substrate self-interstitials (charged or uncharged) to the surface of dielectric layer 324 to adhere to the adsorbed radical and ionic oxidizing species react.
• the distance between the substrate 2 and the plasma electrode 24 in the input region is, for example, in the range of 8 to 15 cm (preferably about 10 cm) is chosen to first achieve radical oxidation / nitridation.
• the distance is, for example, 2 mm to 5 cm (preferably about 2 cm) in order to provide anodic oxidation / nitridation.
• the distance is reduced as the substrate 2 moves through the process chamber 4 to about the middle of the process chamber, and then remains substantially constant until the exit.
• the distance can also be changed via an up or down movement of the conveyor belt.
• the substrate 2 is arranged on the support unit 6, and while in the region of the respective plasma electrodes 24, a plasma burns is rotated.
• the distance between the substrate 2 and the plasma electrode is changed during the layer growth.
• the distance is reduced from a large initial distance in the range of, for example, 8 to 15 cm to a small distance in the range of, for example, 2 mm to 5 cm.
• the distance is in a range of 10 to 2 cm varies.
• process parameters relating to the plasmas such as the power of the plasma electrodes 24, the process gas pressure, a gas inflow as well as a gas composition within the process chamber 4.
• the growth process can alternatively be used to adjust the spacing or additionally be influenced by a grid made of an electrically conductive material.
• a change between a primary anodic oxidation / nitridation and a primary radical oxidation / nitridation at a constant distance between the plasma electrode and the substrate is possible.
• FIGS. 6a and 6b show similar representations to FIGS. 5a and 5b.
• a respective plasma electrode 300 with inner conductor 304 and outer conductor 306 and a substrate 320 from a base substrate 322 with a dielectric layer 324 are shown.
• the distance D between plasma electrode 300 and substrate 320 is the same in FIGS. 6a and 6b.
• positive ions are again shown.
• a grid 330 made of electrically conductive material is shown between the plasma electrode 300 and the substrate 320, which can be acted on by a control unit, not shown, with different electrical bias voltages. If the grid is potential-free, then it essentially does not affect the plasma and the situation shown in FIG. 6 a results, which leads to anodic oxidation / nitridation.
• the grid is energized or grounded, the situation shown in Figure 6b is that primarily only the radicals 312 reach the surface of the dielectric layer 324, resulting in free radical oxidation / nitridation.
• the distance of the grid 330 to the surface of the substrate 320 can optionally also be adjusted.
• the plasma can be operated preferably pulsed during the process.
• the process described above is particularly suitable for forming an oxide layer as a dielectric layer, but may, as mentioned, also form other dielectric layers, such as a nitride layer or an oxide nitride layer.
• Suitable process gases for this purpose are, for example, O 2 , N 2 , NH 3 , NF 3 , D 2 O, Ar, N 2 O, H 2 , D 2 , silane or dichlorosilane or trichlorosilane or dichloroethylene, GeH 4 , boranes (BH 3 B2H6), arsine (ASH 3 ). , Phosphine (PH 3 CF 4 ), tri-methylaluminum ((CH 3 ) 3 Al), SF 6 or carbon-containing other gases or mixtures thereof or the various precursors for producing Hf- or Zr-containing dielectric layers.
• the gas composition and / or the pressure of the process gas can be adjusted during the process.
• the plasma electrodes 24 and the lamps 31 can each individually and be controlled independently of each other. In particular, it is possible to control their performance by means of mathematical functions, such as, for example, a linear function, an exponential function, a quadratic function or other functions.
• the plasma electrodes 24 or the arc lamps / halogen lamps 31 can be set as groups or completely independently of each other, if this is predetermined by a corresponding process.
• a purely thermal see treatment of a substrate take place, in which the substrate is brought to a predetermined temperature via the heating unit, as is the case for example in a post oxidation anneal.
• the transport unit can guide the substrate back through the process chamber when the plasma is switched off.
• different gases can be introduced into the process chamber.
• the substrate would remain in the process chamber beyond the oxidation for a predetermined process duration and be heated by the heating unit.
• Fig. 3 shows a Weibull diagram showing the defect density versus surface charge density of different oxide layers. It can be seen in FIG. 3 that, on the one hand, a prolonged burning time of the respective plasma substantially improves the electrical oxide quality. This effect results not only from the fact that the oxide thickness increases, but also from the fact that too rapidly grown layers outgrow up and thus the interface between Si / SiO 2 improves. Therefore, there is the realization that slow growth with a correspondingly long burning time of the plasma improves the electrical properties.
• the arrangement described above may also be used for cleaning the substrate surface prior to a growth process.
• contaminants or an undefined layer e.g., native S1O2
• a defined layer could be grown by the given process gas.
• cleaning gases one can imagine a reducing gas of pure hydrogen or an arbitrary with noble gases (such as He, Ar, etc.) diluted hydrogen atmosphere or a pure noble gas atmosphere.
• the growth process described above is possible.
• the cleaning effect could also be affected by the distance between the plasma electrode and the substrate and / or the electrical bias on the grid (if any).

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• 2010
  • 2010-12-23 KR KR1020127019514A patent/KR101708397B1/ko active IP Right Grant
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