EP3585920A1 - Source d'évaporation avec ensemble d'isolation thermique - Google Patents
Source d'évaporation avec ensemble d'isolation thermiqueInfo
- Publication number
- EP3585920A1 EP3585920A1 EP18705006.7A EP18705006A EP3585920A1 EP 3585920 A1 EP3585920 A1 EP 3585920A1 EP 18705006 A EP18705006 A EP 18705006A EP 3585920 A1 EP3585920 A1 EP 3585920A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- crucible
- walls
- evaporation source
- region
- sheet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000001704 evaporation Methods 0.000 title claims abstract description 119
- 230000008020 evaporation Effects 0.000 title claims abstract description 119
- 238000002955 isolation Methods 0.000 title claims abstract description 52
- 239000000463 material Substances 0.000 claims abstract description 114
- 238000001816 cooling Methods 0.000 claims abstract description 98
- 238000000151 deposition Methods 0.000 claims abstract description 87
- 239000000758 substrate Substances 0.000 claims abstract description 49
- 229910052751 metal Inorganic materials 0.000 claims abstract description 6
- 239000002184 metal Substances 0.000 claims abstract description 6
- 230000008021 deposition Effects 0.000 claims description 78
- 238000012545 processing Methods 0.000 claims description 32
- 238000007740 vapor deposition Methods 0.000 claims description 26
- 239000011669 selenium Substances 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 13
- 229910052711 selenium Inorganic materials 0.000 claims description 13
- 239000010949 copper Substances 0.000 claims description 12
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 10
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 9
- 229910052802 copper Inorganic materials 0.000 claims description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 6
- 229910002804 graphite Inorganic materials 0.000 claims description 6
- 239000010439 graphite Substances 0.000 claims description 6
- 239000010409 thin film Substances 0.000 claims description 6
- 239000010408 film Substances 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 12
- 238000010438 heat treatment Methods 0.000 description 12
- 229910052750 molybdenum Inorganic materials 0.000 description 11
- 239000011733 molybdenum Substances 0.000 description 11
- 230000008569 process Effects 0.000 description 9
- 238000012423 maintenance Methods 0.000 description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- 238000000429 assembly Methods 0.000 description 6
- 230000000712 assembly Effects 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 239000012809 cooling fluid Substances 0.000 description 6
- 229910001220 stainless steel Inorganic materials 0.000 description 6
- 239000010935 stainless steel Substances 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 5
- 239000006096 absorbing agent Substances 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 239000002826 coolant Substances 0.000 description 4
- 238000005240 physical vapour deposition Methods 0.000 description 4
- 210000002268 wool Anatomy 0.000 description 4
- 238000009826 distribution Methods 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 230000000737 periodic effect Effects 0.000 description 3
- 229910052714 tellurium Inorganic materials 0.000 description 3
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 238000001771 vacuum deposition Methods 0.000 description 3
- MARUHZGHZWCEQU-UHFFFAOYSA-N 5-phenyl-2h-tetrazole Chemical compound C1=CC=CC=C1C1=NNN=N1 MARUHZGHZWCEQU-UHFFFAOYSA-N 0.000 description 2
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 2
- 229910052793 cadmium Inorganic materials 0.000 description 2
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 238000005137 deposition process Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 229910052733 gallium Inorganic materials 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000003779 heat-resistant material Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 125000003748 selenium group Chemical group *[Se]* 0.000 description 2
- 150000003346 selenoethers Chemical class 0.000 description 2
- JBQYATWDVHIOAR-UHFFFAOYSA-N tellanylidenegermanium Chemical compound [Te]=[Ge] JBQYATWDVHIOAR-UHFFFAOYSA-N 0.000 description 2
- 239000004642 Polyimide Substances 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910021417 amorphous silicon Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052795 boron group element Inorganic materials 0.000 description 1
- 229910052729 chemical element Inorganic materials 0.000 description 1
- 238000010549 co-Evaporation Methods 0.000 description 1
- 239000000112 cooling gas Substances 0.000 description 1
- 239000000110 cooling liquid Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000003870 refractory metal Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000002470 thermal conductor Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/24—Vacuum evaporation
- C23C14/243—Crucibles for source material
-
- 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
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
- C23C14/0623—Sulfides, selenides or tellurides
-
- 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
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/54—Controlling or regulating the coating process
- C23C14/541—Heating or cooling of the substrates
-
- 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
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/56—Apparatus specially adapted for continuous coating; Arrangements for maintaining the vacuum, e.g. vacuum locks
- C23C14/562—Apparatus specially adapted for continuous coating; Arrangements for maintaining the vacuum, e.g. vacuum locks for coating elongated substrates
Definitions
- Embodiments of the present disclosure generally relate to evaporation sources used for physical vapor deposition of material onto substrates, and more particularly to an apparatus and method of depositing a material using a physical vapor deposition process on large substrates in a vacuum environment.
- a roll-to-roll deposition process is commonly used to form CIGS (copper- indium-gallium-(di)selenide) solar cell devices.
- CIGS copper- indium-gallium-(di)selenide
- a flexible substrate is generally unwound from a roll and moved past a series of evaporation sources to deposit the different elements used to form the CIGS absorber layer of the solar cell.
- Each evaporation source includes a crucible to heat and vaporize source material that deposits onto the flexible substrate as the substrate moves past the evaporation source. Uniform deposition of the different elements is necessary to produce a high-quality CIGS solar cell.
- CIGS thin film means a CIGS film exhibiting a thickness between 5 and 0.1 micrometers.
- the technical problem underlying the invention is to provide an evaporation source that can provide an improved deposition uniformity for long time periods and to improve the controllability of the deposition process. Furthermore, another problem underlying the invention is to provide an evaporation source which is fast, cheap, resistant, easy to manipulate and maintain, reliable.
- Linear evaporation source means an evaporation source exhibiting a length considerably larger than the width of the evaporation source.
- the length of the evaporation source can be 3 times, preferably 7 times, more preferably 10 times or more larger than the width of the evaporation source.
- low temperature evaporation source means an evaporation source suited to evaporate semi-metals with evaporation temperature lower than 600°C, so as to be suited to evaporate for example selenium, Se, (evaporation temperature typically in the range of 220°C to 400°C) in an industrial roll-to-roll manufacturing coating step.
- high output evaporation source means an evaporation source capable of depositing per unitary length a material flux higher than 5 nm cm/s, preferably higher than 100 nm cm/s, most preferably higher than 150 nm cm/s, so as to be suited to coat large webs and foils in an industrial roll-to-roll manufacturing coating step with acceptable speed.
- modular evaporation source means an evaporation source comprising different separate modules, which are separate individual mechanical parts, which can be mounted together.
- a module of the evaporation source can be the lid, the thermal distributor, the thermal isolation assembly, the cooling assembly, the heat shield assembly, the leg assembly.
- demountable evaporation source means an evaporation source comprising different separate modules and/or parts, which are separate mechanical parts, which can be easily and rapidly demounted and remounted together, so that the single parts of the evaporation source can be individually easily and rapidly mounted, demounted and maintained in a complex large roll-to- roll vapor deposition system for the production of CIGS coatings, where the maintenance and cleaning operations of the components of the evaporation source constitute a serious major problem.
- a demountable and re-mountable module of the evaporation source can be the lid, the thermal distributor, the thermal isolation assembly, the cooling assembly, the heat shield assembly, the leg assembly.
- the different parts and/or modules of the evaporation source are connected and/or fixed together by joint, slot, interlocking, mechanical support, snapping, screwing.
- the pressure of the gas in the evaporation source is between 1 and 10 ⁇ 2 Pa.
- the pressure of the gas outside the evaporation source close to the deposition substrate is between 10 ⁇ 2 and 10 "4 Pa.
- Embodiments of the present disclosure generally relate to evaporation sources used for vapor deposition of material onto substrates and more particularly for controlled coating of large substrates, such as vacuum deposition of selenium on flexible substrates.
- Embodiments of the present disclosure may thus provide an evaporation source for depositing a source material on a substrate, the evaporation source comprising a crucible comprising a base, a first plurality of walls surrounding an interior region of the crucible, the plurality of walls including a first end wall, a second end wall opposite to the first end wall, a first side wall, and a second side wall opposite to the first side wall, a supporting ridge extending inwardly towards the interior region from at least two of the first plurality of walls, a thermal distributor disposed in the interior region of the crucible below the supporting ridge, and a lid disposed on the supporting ridge, the lid comprising two or more adjacently positioned sheets, wherein each sheet comprises a plurality of openings formed therethrough, and the plurality
- Embodiments of the present disclosure may further provide an evaporation source for depositing a source material on a substrate, the evaporation source comprising a crucible comprising a base, a first plurality of walls surrounding an interior region of the crucible, the plurality of walls including a first end wall, a second end wall opposite to the first end wall, a first side wall, and a second side wall opposite to the first side wall, a supporting ridge extending inwardly towards the interior region from the walls, a thermal distributor disposed in the interior region of the crucible below the supporting ridge, and a thermal sensor disposed in the interior region of the crucible below the support ridge and above the thermal distributor.
- Embodiments of the present disclosure may further provide a vapor deposition system for depositing a source material on a substrate comprising a vacuum chamber including one or more walls for enclosing a processing region of the vapor deposition system.
- the vacuum deposition system further includes one or more evaporation sources disposed in the processing region, each evaporation source comprising a crucible having a base and a first plurality of walls surrounding an interior region of the crucible.
- the plurality of walls include a first end wall, a second end wall opposite to the first end wall, a first side wall, and a second side wall opposite to the first side wall.
- the crucible further includes a supporting ridge extending inwardly towards the interior region from at least two of the first plurality of walls.
- a thermal distributor is disposed in the interior region of the crucible below the supporting ridge.
- a lid is disposed on the supporting ridge, the lid including two or more adjacently positioned sheets, wherein each sheet comprises a plurality of openings formed therethrough, and the plurality of openings in each sheet are not aligned with the plurality of openings formed in an adjacently positioned sheet.
- Figure 1 A is a side cross-sectional view of a vapor deposition system according to one embodiment.
- Figure 1 B is a side cross-sectional view of an evaporation source to be used in the vapor deposition system of Figure 1 B, according to one embodiment.
- Figure 2A is a perspective view of a crucible assembly to be used in the evaporation source of Figure 1 B, according to one embodiment.
- Figure 2B is a side cross-sectional view of a crucible of the crucible assembly of Figure 2A, according to one embodiment.
- Figure 3A is a perspective view of a thermal distributor to be used in the evaporation source of Figure 1 B, according to one embodiment.
- Figure 3B is a close-up sectional view of a portion of the thermal distributor of Figure 3A, according to one embodiment.
- Figure 4A is a side sectional view of a lid assembly mounted on an empty crucible, according to one embodiment.
- Figure 4B is a top view of a single sheet of the lid assembly of Figure 4A, according to one embodiment.
- Figure 4C is a close-up sectional view of the single sheet of the lid assembly shown in Figure 4B, according to one embodiment.
- Figure 5 is a perspective view of a thermal isolation assembly to be used in the evaporation source of Figure 1 B, according to one embodiment.
- Figure 6A is a perspective of a cooling assembly to be used in the evaporation source of Figure 1 B, according to one embodiment.
- Figure 6B is a bottom view of the cooling assembly, according to the embodiment of Figure 6A.
- Figure 7A is a perspective view of a heat shield assembly to be used in the evaporation source of Figure 1 B, according to one embodiment.
- Figure 7B is a perspective sectional view of a side wall portion and a portion of the frame of the heat shield assembly shown in Figure 7A, according to one embodiment.
- Figure 7C is a close-up sectional view of a portion of Figure 7B, according to one embodiment.
- Figure 7D is a perspective sectional view of a base portion of the heat shield assembly, according to one embodiment
- Embodiments of the present disclosure generally relate to evaporation sources used for physical vapor deposition of material onto substrates and more particularly for controlled coating of large substrates, such as vacuum deposition of selenium on flexible substrates.
- Said evaporation sources may, for example, be used within vacuum chambers where a plurality of evaporation source types, some of which may have physical and design characteristics different from the evaporation source 100 described below, are configured to implement a co-evaporation process.
- FIG. 1A is a side cross-sectional view of a vapor deposition system 10 according to one embodiment.
- the vapor deposition system 10 is a roll-to-roll type vapor deposition system for depositing material layers onto a flexible substrate 50.
- the vapor deposition system 10 includes a vacuum chamber 1 1 including one or more walls 12 for enclosing a processing region 15 of the vapor deposition system 10.
- the vapor deposition system 10 can further include one or more evaporation sources 90 and one or more evaporation sources 100, which are both disposed within the processing region 15.
- the evaporation sources 90 may be used to deposit materials, such as copper (Cu), indium (In), and gallium (Ga).
- the evaporation sources 100 may be used to deposit materials that evaporate at a substantial rate below about 600°C at the vacuum pressure maintained within vacuum chamber 1 1 , such as selenium (Se), tellurium (Te), cadmium (Cd), or Zinc (Zn).
- the processing region 15 of the vacuum chamber 1 1 is maintained at a constant vacuum pressure, such as about 2* 10 "3 Pa.
- the vapor deposition system 10 includes one or more sets 22, 23 of two or more evaporation sources 90, 100 that are positioned within the processing region 15 to deposit material layer(s) onto the substrate 50 as the substrate 50 is transferred through the processing region 15.
- the substrate 50 can include a web of flexible polyimide or stainless steel material. The substrate 50 can be transferred through the processing region 15 from a feed roll 41 , over tensioning rolls 51 , 52, 53, 54 and to a take-up roll 42.
- the evaporation sources 90, 100 can each contain material that can be heated to a molten state, so that the heated material evaporates to coat portions of the substrate 50 as the substrate 50 passes near each evaporation source 90, 100.
- the sets 22 and 23 of evaporation sources 90, 100 may be oriented so as to follow the path of the substrate 50 through the processing region 15.
- the vapor deposition system 10 is particularly appropriate for deposition of materials to create photovoltaic cells, particularly CIGS (copper-indium-gallium-(di)selenide) solar cells.
- CIGS copper-indium-gallium-(di)selenide
- the semiconductive photovoltaic layer may, for example, be made of an "ABC" material, wherein "A” represents elements in group 1 1 of the periodic table of chemical elements (e.g., copper (Cu) or silver (Ag)), “B” represents elements in group 13 of the periodic table (e.g., indium (In), gallium (Ga), or aluminum (Al)), and “C” represents elements in group 16 of the periodic table (e.g., sulfur (S), selenium (Se), or tellurium (Te)).
- An example of an ABC 2 material is the Cu(ln,Ga)Se 2 semiconductor also known as a CIGS material.
- thin-film absorber materials include cadmium telluride (CdTe) and its variants, perovskites, amorphous silicon, thin-film silicon, as well as absorber materials used to manufacture dye-sensitized solar cells or organic solar cells.
- Figure 1 B is a side cross-sectional view of one of the evaporation sources 100, according to one embodiment.
- the evaporation source is used as a selenium evaporation source, but the evaporation source 100 may also be used as an evaporation source for other materials, such as a conductive or dielectric material, such as tellurium (Te), cadmium (Cd), Zinc (Zn), or other useful material.
- a conductive or dielectric material such as tellurium (Te), cadmium (Cd), Zinc (Zn), or other useful material.
- the evaporation source 100 includes a crucible assembly 200 that includes a crucible 201 and heater 220.
- the heater 220 provides heat to melt and evaporate the deposition material 75 (e.g., selenium) in an interior region 204 of the crucible 201 during processing.
- the crucible assembly 200 is described in further detail below in reference to Figures 2A and 2B.
- the evaporation source 100 further includes a thermal distributor 300 disposed within the interior region 204 of the crucible 201 .
- the thermal distributor 300 is used to uniformly distribute heat to the deposition material 75 during processing.
- the thermal distributor 300 is described in further detail below in reference to Figures 3A and 3B.
- the evaporation source 100 further includes a lid assembly 400 disposed above the thermal distributor 300.
- the lid assembly 400 can be positioned on a supporting ridge 210 of the crucible 201 .
- the lid assembly 400 thermally isolates the interior region 204 of the crucible 201 from the areas above the crucible 201 .
- the lid assembly 400 includes openings 402 (see Figure 4A) to direct evaporated deposition material towards the substrate 50 (see Figure 1A) during processing.
- the openings 402 are sized to control the effusion of material from the evaporation source 100.
- the opening diameters are between about 1 and about 5 millimeters (mm) in size, and are spaced a distance between about 10 and about 100 mm apart.
- the lid assembly 400 is described in further detail below in reference to Figures 4A, 4B, and 4C.
- the evaporation source 100 further includes a thermal isolation assembly 500 disposed around one or more of the walls 202, such as all of the walls 202 of the crucible 201 .
- the thermal isolation assembly 500 isolates the walls and top of the crucible 201 from variations in thermal loads coming from outside of the thermal isolation assembly 500, such as heat coming from one of the other evaporation sources 100 in the vacuum chamber 1 1 .
- the thermal isolation assembly 500 is described in further detail below in reference to Figure 5.
- the evaporation source 100 further includes a cooling assembly 600.
- the cooling assembly 600 includes a cooling plate 602 disposed below the crucible 201 .
- the cooling plate 602 can be used too rapidly cool the deposition material 75 when processing is completed or stopped.
- the cooling assembly 600 may further include one or more cooling tubes 604.
- a sheet 616 material having a high thermal conductivity, such as graphite may be disposed between the cooling plate 602 and the crucible 201 to further promote thermal contact between the cooling plate 601 and the crucible 201 .
- the sheet 616 may also help provide some temperature regulation and control of the crucible 201 .
- the cooling assembly 600 is described in further detail below in reference to Figures 6A and 6B.
- the evaporation source 100 further includes a heat shield assembly 700 disposed around the thermal isolation assembly 500 and the cooling assembly 600 to further prevent external heat loads from causing thermal disturbances within the interior region 204 of the crucible 201 .
- the heat shield assembly 700 includes one or more side wall portions 710, one or more base portions 720, and a lid portion 730. The heat shield assembly 700 is described in further detail below in reference to Figures 7A-7D.
- the evaporation source 100 uses a modular design to simplify cleaning and other maintenance procedures that are commonly required when using physical vapor deposition sources.
- the crucible assembly 200, the thermal isolation assembly 500, and the heat shield assembly 700 are all spaced apart and/or separable from each other allowing maintenance to be performed on one of these assemblies without disturbing the other assemblies.
- the lid assembly 400 and the lid portion 730 of the heat shield assembly are easily removable as described below, which allows easy access to the interior region 204 of the crucible 201 .
- the evaporation source 100 further includes a leg assembly 800.
- the leg assembly 800 provides support for other assemblies within the evaporation source 100, such as the thermal isolation assembly 500, the cooling assembly 600, and the heat shield assembly 700. Adjustment and positioning of the leg assembly 800 also determines where the evaporation source 100 is positioned within the vacuum chamber 1 1 .
- the feet 820 of the leg assembly 800 are positioned on a portion of the wall 12 of the vapor deposition system 10.
- the leg assembly 800 includes a plurality of legs 810 and a plurality of feet 820 that are used to level and vertically position the evaporation source 100 relative to the substrate 50 and thermally isolate the evaporation source 100 from portions of the vapor deposition system 10.
- the leg assembly 800 may include between about four feet 820 to about ten feet 820 that are positioned to evenly support the evaporation source 100. Each foot 820 may be connected to one to about eight legs 810, such as five legs
- Each leg 810 includes an upper element 81 1 and a lower element 812 that are attached to each other.
- the upper element 81 1 is also attached to one of the assemblies, such as the thermal isolation assembly 500, the cooling assembly 600, or the heat shield assembly 700.
- the upper element 81 1 has external threads (not shown) at either end (i.e., top and bottom in Figure 1 B) for connecting to the internal threads (not shown) formed on the lower element 812 and a portion of one of the assemblies 500, 600 or 700.
- the height of the assemblies 500, 600 or 700 can be adjusted by varying the amount that the upper element 81 1 is threaded into the lower element 812.
- the lower element 812 has a larger diameter than the upper element
- each leg 810 is attached to one of the feet 820, for example, by using external threads (not shown) on the lower element 812 to connect to internal threads (not shown) on the foot 820.
- Each foot 820 can be attached to the vacuum chamber 1 1 .
- FIG. 2A is a perspective view of the crucible assembly 200, according to one embodiment.
- the crucible assembly 200 includes the crucible 201 and the heater 220 disposed around the walls 202 of the crucible 201 .
- the crucible 201 can be formed of a material having high-thermal conductivity, such as molybdenum, graphite or stainless steel.
- the crucible 201 includes one or more walls 202, such as a plurality of walls 202, and a base 203.
- the plurality of walls 202 surround the interior region 204 of the crucible 201 .
- the crucible 201 includes an opening 208 (see Figure 2B) above the interior region 204 of the crucible 201 .
- the crucible 201 can have a shape substantially similar to a rectangular prism having an open top.
- An evaporation source 100 having a crucible 201 with a substantially rectangular shape, such as the crucible 201 is referred to herein as a linear evaporation source.
- the walls 202 of the crucible 201 can include a first end wall 202i, a second end wall 202 2 opposite to the first end wall 202i, a first side wall 202 3 , and a second side wall 202 4 opposite to the first side wall 202 3 .
- the first side wall 202 3 connects the first end wall 202i to the second end wall 202 2 along a first side 21 1 of the crucible 201.
- the second side wall 202 4 connects the first end wall 202i to the second end wall 202 2 along a second side 212 of the crucible 201 .
- the side walls 202 3 , 202 4 each have a horizontal length (Y- direction in Figure 2A) extending in a direction from the first end wall 202i to the second end wall 202 2 .
- the end walls 202i, 202 2 each have a horizontal length (X-direction in Figure 2A) extending in a direction from the first side wall 202 3 to the second side wall 202 4 .
- the side walls 202 3 , 202 4 generally have a horizontal length that is longer than the length of the end walls 202i, 202 2 .
- the side walls 202 3 , 202 4 have a horizontal length from about 50 mm to about 5000 mm (e.g., about 1 120 mm), and the end walls 202i, 202 2 have a horizontal length from about 20 mm to about 300 mm (e.g., about 96 mm).
- a ratio of the length of the side walls 202 3 , 202 4 to the horizontal length of the end walls 202i, 202 2 is from about 5:1 to about 500:1.
- the horizontal length of the sidewalls 202 3 , 202 4 is related to the width of the substrate 50 (see e.g., the dimension of the substrate 50 in the Y-direction of Figure 1A).
- the horizontal length of the side walls 202 3 , 202 4 may be longer than the width of the substrate 50 in the Y-direction by about 1 mm to about 250 mm, such as about 120 mm.
- the end walls 202i, 202 2 and the side walls 202 3 , 202 4 each have a height (i.e., in the Z-direction of Figure 2A) from about 30 mm to about 700 mm, such as about 150 mm.
- the crucible 201 further includes the ridge 210 for supporting the lid assembly 400 (see Figure 1 B) as described above.
- the ridge 210 extends at least along two of the opposing side walls 202 3 , 202 4 , and in some embodiments around each of the walls 202 of the crucible 201.
- the ridge 210 may extend along the entire inner periphery of the wall 202 of that crucible.
- the ridge 210 is positioned at a vertical location (Z-direction in Figure 2A) between the thermal distributor 300 (see Figure 1 B) and the top 206 of the crucible 201.
- Having the ridge 210 positioned above the thermal distributor 300 ensures that the molten deposition material 75 does not contact the lid assembly 400 because the fill level of the molten deposition material 75 is kept below the top of the thermal distributor 300 and because the lid assembly 400 does not extend below the ridge 210.
- Having a ridge 210 along the entire inner periphery of the crucible 201 ensures that, when lid assembly 400 is in position, there is no direct evaporation path to locations outside the crucible 201 that bypasses the sheets 404 of the lid assembly 400 described below.
- the crucible 201 can further include at least one first groove 261 for allowing placement of at least one thermal sensor 250, such as a thermocouple.
- the first groove 261 extends from the top 206 of the crucible 201 down to a vertical location on one of the walls 202 below the ridge 210 and above the thermal distributor 300 (see Figure 1 B).
- the first groove 261 may be located, for example, at a center position along the length direction (Y-direction of Figure 2A) of one of the side walls 202 3 , 202 4 .
- the first groove 261 allows the thermal sensor 250 to be routed from outside the crucible 201 to the interior region 204 of the crucible 201 without impeding the positioning of the lid assembly 400 on the ridge 210.
- the thermal sensor 250 may be routed to avoid thermal contact with the lid assembly 400, so that the lid assembly 400 does not interfere with measurements made by the thermal sensor 250.
- the thermal sensor 250 can extend inwardly toward the interior region 204 of the crucible 201 from the first groove 261 at a vertical location below the ridge 210 and above the thermal distributor 300, so that the thermal sensor 250 remains above the molten deposition material 75 during processing.
- the thermal sensor 250 can extend inwardly at vertical location from about 1 mm to about 20 mm below the ridge 210, such as about 10 mm below the ridge 210.
- the vertical location of the ridge 210 can also correspond to the lowest position of the lid assembly 400 (see Figure 1 B), so that a vertical distance between the thermal sensor 250 and the ridge 210 corresponds to a vertical distance between the thermal sensor 250 and the lid assembly 400.
- the thermal sensor 250 measures a temperature of the vapor of the deposition material 75 during processing. Measuring the temperature of the vapor of the deposition material 75 will allow a temperature control system to accurately and consistently determine the temperature of the surface of the molten deposition material 75, which is used to control the evaporation rate of the molten deposition material 75. Thus, by measuring the temperature of the vapor of the deposition material 75, the temperature control system (not shown) can be used to adjust the power supplied to the heater 220 to control the evaporation rate of the deposition material 75. Accurate control of the evaporation rate of the deposition material 75 leads to better control of the deposition rate, and also provides a more uniform deposition of the deposition material 75 across the substrate 50, which improves product quality and yield.
- thermocouple placing a thermal sensor, such as a thermocouple in the deposition material 75 causes numerous problems.
- the evaporation rate is more dependent on the temperature at the surface of the deposition material 75 than a temperature at some depth of the deposition material 75, so controlling the temperature at a given depth of the deposition material provides inadequate control of the deposition rate.
- this thermal sensor can become exposed as the fill level of the deposition material decreases during processing, which drastically alters the thermal environment of the thermocouple leading to measurements that are not useful for controlling the deposition rate of the deposition material 75.
- servicing of the thermocouple is much more difficult when the thermocouple is surrounded by the deposition material 75 that has solidified after use.
- the temperature control system is generally used to control one or more components found in the vapor deposition system 10.
- the temperature control system is generally designed to facilitate the control and automation of the components within the vapor deposition system 10 and typically includes a central processing unit (CPU) (not shown), memory (not shown), and support circuits (or I/O) (not shown).
- the CPU may be one of any form of computer processors that are used in industrial settings for controlling various system functions, substrate movement, chamber processes, and control support hardware (e.g., sensors, motors, evaporation sources, heaters, etc.), and monitor the processes performed in the system (e.g., substrate support temperature, chamber process time, I/O signals, etc.).
- the memory is connected to the CPU, and may be one or more of a readily available memory, such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote.
- Software instructions and data can be coded and stored within the memory for instructing the CPU.
- the support circuits are also connected to the CPU for supporting the processor in a conventional manner.
- the support circuits may include cache, power supplies, clock circuits, input/output circuitry, subsystems, and the like.
- a program (or computer instructions) readable by the temperature control system determines which tasks are performable on a substrate in the vapor deposition system 10.
- the program is software readable by the temperature control system that includes code to perform tasks relating to monitoring, execution and control of the movement, support, and/or positioning of a substrate along with the various process recipe tasks and various chamber process recipe steps being performed in the temperature control system (e.g., temperature control of the evaporation source 100).
- the crucible 201 may further include a second groove 262 for allowing placement of a level sensor (not shown), such as a resistance depth probe.
- a level sensor such as a resistance depth probe.
- the second groove may be placed on the opposing side wall (e.g., side wall 202 4 ) from the side wall (e.g., side wall 202 3 ) including the thermal sensor 250.
- a resistance depth probe (not shown) extends into the molten deposition material 75 during processing to measure the varying level of the molten deposition material 75.
- the heater 220 can include a heating cable 222, such as a sheathed heating cable.
- the heating cable 222 can be distributed across each of the walls 202 in a pattern using a plurality of loops 224. Portions of the heating cable 222 at a given vertical location (i.e., Z-position in Figure 2A) may be separated from other portions of the heating cable 222 at the same vertical location by about 8 mm to about 50 mm, such as by about 20 mm.
- Each loop 224 can extend from a location close to the base 203 of the crucible 201 to a location close to the top 206 of the crucible 201 .
- the change in height (e.g., the amplitude) of the heating cable 222 in each loop covers a vertical distance of at least 60% of the height of the walls 202, such as at least 90% of the height of the walls 202.
- the loops 224 allow thermal expansion of the heating cable 222 with respect to the crucible 201 .
- Electric power may be applied to the heating cable 222 to provide the heat to the crucible 201 by a power supply that is coupled to the temperature control system.
- the heating cable 222 may be secured to the walls 202 of the crucible 201 using mechanical elements, for example, clamps (not shown) that can be fastened to the walls 202 of the crucible 201 .
- the crucible assembly 200 can further include one or more sheets 214 of material having a high thermal conductivity, such as graphite, disposed between heating cable 222 and the one or more walls 202 of the crucible 201 to promote heat transfer between the heater 220 and the crucible 201 .
- the one or more sheets 214 can be secured using the same clamps and fasteners used to secure the heating cable 222 to the walls 202 of the crucible 201 .
- Figure 2B is a side cross-sectional view of the crucible 201 taken along the line 2B of Figure 2A, according to one embodiment.
- one or more of the walls 202 of the crucible 201 may include a tapered portion 227 between the base 203 and the ridge 210 of the crucible 201 .
- the tapered portion 227 extends the entire vertical distance (Z-direction) from the base 203 to the ridge 210.
- the tapered portion 227 may be angled outwardly from the base 203 by about 0 degrees to about 5 degrees from a vertical direction, such as by about 2 degrees to about 4 degrees.
- Including a tapered portion 227 on the lower part of the walls 202 allows for the relief of the intrinsic or extrinsic stress created by the melting or solidifying of the evaporation material on the crucible walls 202 when the deposition material 75 is heated or cooled.
- selenium has a coefficient of thermal expansion of 37E-6 m/m*K, and the expansion of heated selenium can cause significant stress on the walls 202 of the crucible 201 before melting.
- the angle of the tapered portion 227 is only from about 0 degrees to about 5 degrees, the surface area of the exposed surface of the molten deposition material 75 does not change substantially with the fill level of deposition material 75.
- the evaporation rate of the deposition material 75 is largely affected by the surface area of the exposed surface of molten deposition material 75, and the temperature of the vapor of the deposition material 75.
- having the exposed surface area of the molten deposition material 75 remain relatively constant despite changes in fill level allows the evaporation rate of deposition material 75 to be more easily controlled by controlling the temperature, for example by using measurements from the thermal sensor 250 described above.
- the tapered portion 227 has a greater thickness at the base 203 than at higher vertical locations, such as the ridge 210.
- the tapered portion 227 may have a thickness from about 6 mm to about 100 mm at the base 203 and thickness from about 4 mm to about 60 mm at the ridge 210.
- the thickness of the walls 202 at the top 206 can be, for example, from about 2 mm to about 40 mm.
- the support ridge 210 can extend inwardly from the walls 202 by about 1 mm to about 20 mm.
- the portions of the walls 202 above the tapered portion 227, such as portions above the ridge 210 can be substantially vertical.
- Figure 3A is a perspective view of the thermal distributor 300 described above in reference to Figure 1 B, according to one embodiment.
- Figure 3B is a close-up sectional view of a portion of the thermal distributor of Figure 3A, according to one embodiment.
- the thermal distributor 300 is placed in the interior region 204 of the crucible 201 and is used to uniformly distribute heat to the deposition material 75 (see Figure 1 B) during processing.
- the thermal distributor 300 can be fabricated from a material that is heat-resistant, chemically compatible with the deposition material 75 and has a high thermal conductivity, such as refractory metals, such as molybdenum.
- the thermal distributor 300 can be sized in relation to interior region 204 of the crucible 201 to ensure good thermal contact between the thermal distributor 300 and the walls 202 of the crucible 201 .
- the thermal distributor 300 includes a body 302 formed of one or more first portions 310 and one or more second portions 320.
- the first portions 310 can extend in a first direction (i.e., Y-direction in Figure 3), such as the length direction of the side walls 202 3 , 202 4 .
- the first portions 310 can be spaced apart in a second direction (i.e., the X-direction in Figure 3) perpendicular to the first direction.
- the second portions 320 can extend in the second direction (i.e., X-direction in Figure 3), such as the length direction of the end walls 202-1 , 202 2 .
- the second portions 320 can be spaced apart in the first direction along the length of the first portions 310.
- the first portions 310 can be joined to the second portions 320 to give the thermal distributor 300 a grid structure when viewed from above.
- the thermal distributor may include a metal wool, for example molybdenum wool or stainless steel wool. In one embodiment, this metal wool may can be, for example, sandwiched between two grids.
- the first portions 310 and the second portions 320 can be formed of molybdenum sheets having a thickness from about 0.2 mm to about 5 mm.
- the first portions 310 can have a thickness in the X-direction of about 0.2 mm to about 5 mm.
- the first portions 310 and the second portions 320 can have a height (Z-direction in Figure 3) of about 5 mm to about 500 mm, such as about 60 mm.
- the height of the portions 310, 320 can be set to be higher than the expected level of the deposition material 75 in the crucible 201 .
- the first portions 310 extending in the first direction may be spaced apart in the second direction by about 10 mm to about 40 mm, such as about 20 mm.
- the second portions 320 extending in the second direction may be spaced apart in the first direction by about 20 mm to about 160 mm, such as about 80 mm.
- Each of the first portions 310 and the second portions 320 can also include a plurality of holes 315.
- the plurality of holes 315 may be distributed along the lengths of the first portions 310 and the second portions 320 in a repeating pattern.
- the plurality of holes 350 can be arranged in a hexagonal close-pack pattern (e.g., one hole 350 surrounded by six holes 350).
- the holes 315 can have, for example, a diameter from about 2 mm to about 40 mm, such as about 6 mm.
- the holes 315 may be spaced apart from each other along the length of the given portion 310, 320 from about 4 mm to about 80 mm, such as about 12 mm. In some embodiments, the distance between the holes 315 along the lengths of the given portion 310, 320 is about twice the diameter of the holes 315.
- the thermal distributor 300 can homogenize the surface temperature of the molten deposition material 75 during processing.
- the surface temperature of the molten deposition material 75 is what controls the evaporation rate and ultimately the deposition rate of the deposition material 75 onto the substrate 50.
- Many deposition materials, such as selenium, are poor thermal conductors, so using the thermal distributor 300 formed of a material having a high thermal conductivity allows the heat from the heater 220 to be uniformly distributed to the deposition material 75.
- the thermal distributor 300 having high thermal conductivity also aids in rapid cooling of the deposition material 75 after horizontal processing is completed.
- the spacing of the first portions 310 and second portions 320, relative to themselves, may be non-symmetric to assure that the thermal uniformity in the interior region 204 of the crucible 201 is uniform.
- a spacing between the second portions 320 in a first region of the interior 204 can be shorter than the spacing between the second portions 320 in a second region of the interior 204, wherein the first region is closer to one of the end walls 202i, 202 2 than the second region is to one of the end walls 202i, 202 2 .
- a spacing between the first portions 310 in a third region of the interior 204 can be shorter than the spacing between the first portions 310 in a fourth region, wherein the third region is closer to one of the side walls 202 3 , 202 4 than the fourth region is to one of the side walls 202 3 , 202 4 .
- FIG. 4A is a side sectional view of the lid assembly 400 mounted on an empty crucible 201 , according to one embodiment.
- the lid assembly 400 includes openings 402 to direct evaporated deposition material 75 towards the substrate 50 during processing.
- the lid assembly 400 may be formed from a heat resistant and thermally conductive material, such as molybdenum or graphite.
- the lid assembly 400 includes a stack 410 of a plurality of sheets 404 stacked on top of each other, such as from 2 to about 20 sheets, such as from 5 to 12 sheets, such as 10 sheets.
- each sheet 404 includes a plurality of openings 402 to direct evaporated deposition material towards the substrate 50 during processing.
- the sheets 404 can be formed of molybdenum, such as sheets having a thickness in the vertical direction of Figure 4A from about 0.1 mm to about 0.4 mm, such as about 0.2 mm.
- the lid assembly 400 may completely cover the opening 208 of the crucible 201 .
- Figure 4B is a top view of a single sheet 404 of the lid assembly 400 of Figure 4A, according to one embodiment.
- Figure 4C is a close-up sectional view of a portion of the single sheet 404 of the lid assembly 400 shown in Figure 4B, according to one embodiment.
- the sheets 404 may include bumps 406 distributed across at least one surface of the sheet 404 that includes the openings 402, such as a first surface 41 1.
- the first surface 41 1 may be a top surface or a bottom surface of the sheet 404.
- the bumps 406 create separation between the sheets 404 of the stack 410 to minimize thermal contact between the sheets 404 in the stack 410. In some embodiments, there can be as many bumps 406 as there are openings 402.
- each bump 406 can have a cross section that narrows as the bump extends away from the first surface 41 1 .
- Figure 4A shows the bumps 406 having a triangular cross section extending from the sheets 404 to a point.
- Figure 4C shows another view of the bumps 406 having a conical shape.
- the number of openings 402 per unit area through the first surface 41 1 may vary along the length of the sheet 404 from a first end 421 to a second end 422.
- the length of the sheet 404 can be the same direction as the length of one of the side walls 202 3 , 202 4 of the crucible 201 (see Figure 2A).
- the sheet 404 may include a higher concentration of openings 402 on regions of the first surface 41 1 that are closer to one of the ends 421 , 422 than to a center 404C of the first surface 41 1 .
- a first region of the first surface 41 1 contacting one of the ends 421 , 422 may include more openings 402 than a second region of the first surface 41 1 that covers the same area as the first region and includes the center 404C.
- Having a higher concentration of openings 402 through regions of the first surface 41 1 near the ends 421 , 422 can enable a more homogeneous deposition of the deposition material 75 on the substrate 50.
- the higher concentration of openings 402 near the ends 421 , 422 may help compensate for the tendency of a source with a lengthwise uniform nozzle to evaporate a greater flux of material towards its middle than towards its ends.
- the openings 402 can have a diameter from about 0.5 mm to about 5 mm, such as 1 mm.
- the openings 402 may be spaced apart from each other in a hexagonal pattern (e.g., one opening 402 surrounded by six other openings 402) across the first surface 41 1 .
- the openings 402 may be spaced apart from each other by about 10 mm to about 100 mm, such as about 20 mm, in the width direction of the first surface 41 1 (i.e., the direction parallel to the ends 421 , 422).
- the openings 402 may be spaced apart from each other by about 20 mm to about 200 mm, such as by about 40 mm, in the length direction of the first surface 41 1 (i.e., the direction perpendicular to the ends 421 , 422).
- the openings 402 of a given sheet 404 may be staggered relative to the openings 402 of the sheets 404 directly above and directly below the given sheet 404. Staggering the openings 402 prevents a line of sight through the stack 410 of sheets 404. A line of sight through the stack 410 of sheets 404 can cause heat shielding problems as well as problems associated with the distribution of the vapor of the deposition material 75. For example, the staggering helps to randomize the direction of the vapor of the deposition material 75, so that a more homogenous deposition on the substrate 50 is achieved. A higher number of sheets 404 can improve the heat shielding effects of the stack 410 relative to a lower number of sheets 404.
- the openings 402 of the topmost sheet 404 of the stack 410 can have the largest effect on the distribution of the vapor of the deposition material 75.
- the lid assembly 400 is removable from the supporting ridge 210 of the crucible 201 allowing for the crucible 201 to be rapidly filled with deposition material 75 when the lid assembly 400 is removed. For example, selenium pellets may be poured into the crucible 201 when the lid assembly 400 is removed. Furthermore, having a lid assembly 400 that is easily removed allows for easy replacement of the lid assembly 400 with a different lid assembly, for example, a different lid assembly having a different distribution of openings that can be used for a different product.
- FIG. 5 is a perspective view of the thermal isolation assembly 500, according to one embodiment.
- the thermal isolation assembly 500 is generally used to isolate the crucible assembly 200 from external thermal loads found within the vapor deposition system 10.
- the crucible assembly 200 would receive heat from other sources in the vacuum chamber 1 1 , such as other evaporation sources.
- these other sources of heat would generally heat the crucible assembly 200 and the deposition material 75 in a nonuniform way, such as mainly near the end walls 202i, 202 2 .
- a single thermal sensor 250 has no way of measuring this non-uniformity.
- the heater 220 cannot heat in a way to remove these thermal non-uniformities. Consequently, prevention of these thermal non-uniformities by using the thermal isolation assembly 500 is a clear improvement over evaporation sources not including a thermal isolation assembly, such as the thermal isolation assembly 500.
- the heat shield assembly 700 and the lid assembly 400 can each use heat-reflecting sheets, such as molybdenum sheets, which can further shield the crucible assembly 200 from external thermal loads.
- the thermal isolation assembly 500 includes one or more vertical walls 502 and a top plate 504.
- the one or more vertical walls 502 can surround the crucible assembly 200.
- the one or more vertical walls 502 can include a first end wall 502i, a second end wall 502 2 opposite to the first end wall 502i, a first side wall 502 3 , and a second side wall 502 4 opposite to the first side wall 502 3 .
- the first side wall 502 3 connects the first end wall 502i to the second end wall 502 2 along a first side 51 1 of the thermal isolation assembly 500.
- the second side wall 502 4 connects the first end wall 502i to the second end wall 5022 along a second side 512 of the thermal isolation assembly 500.
- the side walls 502 3 , 502 4 each have a horizontal length extending in a direction from the first end wall 502i to the second end wall 502 2 .
- the end walls 502i, 5022 each have a horizontal length extending in a direction from the first side wall 502 3 to the second side wall 502 4 .
- the side walls 502 3 , 502 4 generally have a horizontal length that is longer than the horizontal length of the end walls 502i, 502 2 .
- the side walls 502 3 , 502 4 have a horizontal length from about 50 mm to about 5100 mm (e.g., about 1200 mm), and the end walls 502-I , 502 2 have a horizontal length from about 20 mm to about 400 mm (e.g., about 120 mm).
- the walls 502 can surround the crucible assembly 200 and can be spaced apart from a nearest part of the crucible assembly by about 4 mm to about 100 mm, such as by about 20 mm.
- the nearest part of the crucible assembly 200 to the walls 502 can be a heater clamp (not shown) that can be used to secure the heater 220 to the crucible 201 or a crucible alignment tab (not shown) that can be used to align crucible assembly 200 on the cooling assembly 600 described below.
- the one or more of the walls 502 can be formed of a material having high thermal conductivity, such as copper.
- each of the one or more vertical walls 502 can be formed of a single plate but may also be formed of a stack of a plurality of plates (not shown) which can be joined together, such as by use of a fastener or other material joining process.
- each vertical wall 502 includes four plates which are fastened to each other. The plates can each have a thickness in the direction in which the stack is formed from about 4 mm to about 60 mm.
- the top plate 504 of the thermal isolation assembly 500 can be positioned on and attached to the one or more vertical walls 502, such as by use of a fastener.
- the top plate 504 may have a thickness in a vertical direction (i.e., Z-direction of Figure 5) from about 1 mm to about 20 mm, such as about 3 mm.
- the top plate 504 can have a horizontal length in the Y-direction that is the same as the horizontal length of the side walls 502 3 , 502 4 .
- the top plate 504 can have a width in the X-direction that is the same as the horizontal length of the end walls 502-I , 502 2 .
- the top plate 504 of the thermal isolation assembly 500 can be disposed above the top 206 of the crucible 201 .
- the top plate 504 can be about 5 mm to about 20 mm above the top 206 of the crucible 201 .
- Wiring for inputs and outputs (I/O), such as the thermal sensor 250, can be routed through the evaporation source 100 in the spaces between the crucible assembly 200 and the thermal isolation assembly 500, such as the space between the walls 202 of the crucible assembly 200 and the walls 502 of the thermal isolation assembly 500, and the space between the top 206 of the crucible assembly 200 and the top plate 504 of the thermal isolation assembly 500.
- the top plate 504 can have an opening 506 overlying the opening 208 of the top 206 of the crucible 201 .
- the opening 506 of the top plate 504 can be substantially the same size as the opening 208 of the top 206 of the crucible 201 .
- the opening 506 can be aligned with the opening 208 such that the opening 506 overlies substantially all of the opening 208.
- the thermal isolation assembly 500 is configured so that no significant amount of thermal radiation from an external device, for example an external evaporation source, may propagate directly to the crucible 201 .
- the thermal isolation assembly 500 does not include a base.
- the bottom of the walls 502 can be positioned below the bottom of the crucible assembly 200. In some embodiments, the bottom of the walls 502 are also positioned below the bottom of the cooling assembly 600 described in further detail below by about 20 mm to about 500 mm.
- the leg assembly 800 can connect the thermal isolation assembly 500 to the floor of the vacuum chamber 1 1 (see Figure 1A) to support the weight of the thermal isolation assembly 500.
- the thermal isolation assembly 500 can further include one or more cooling tubes 520.
- the cooling tubes 520 can be disposed around and/or adjacent to the one or more walls 502.
- the one or more cooling tubes 520 can have a supply 524 on the first side 51 1 of the thermal isolation assembly 500 and a return 525 on the second side 512 of the thermal isolation assembly 500.
- the supply 524 and the return 525 can be connected through a vacuum feedthrough (not shown) of the vacuum chamber 1 1 (see Figure 1A) to an external cooling system (not shown).
- water may be used as the coolant, but other coolants may also be used.
- the one or more cooling tubes 520 can be disposed in one or more grooves 522 of the outer surface 523 of the side walls 502 3 , 502 4 .
- the outer surface 523 faces away from the interior region 204 of the crucible 201 (see Figure 1 B). Cooling fluid may be distributed through the cooling tube(s) 520 to prevent external sources of heat from causing thermal disturbances within the interior region 204 of the crucible 201.
- the one or more cooling tubes 520 can have a diameter from about 4 mm to about 10 mm, such as about 6 mm.
- the one or more cooling tubes 520 can make multiple horizontal passes (i.e., in the Y-direction of Figure 5) along the horizontal lengths of the side walls 502 3 , 502 4 , such as about 4 horizontal passes. These horizontal passes may be spaced apart from each other by about 8 mm to about 200 mm, such as by about 30 mm.
- the thermal isolation assembly 500 includes one cooling tube 520 that makes multiple horizontal passes (e.g., 4 horizontal passes) along the first side wall 502 3 , wraps around the first end wall 502i, and then makes multiple horizontal passes (e.g., 4 horizontal passes) along the second side wall 502 4 .
- the spacing between the horizontal passes of the cooling tube 520 along one of the side walls 502 3 , 502 4 can vary between about 10 mm to about 100 mm.
- FIG 6A is a perspective of the cooling assembly 600, according to one embodiment.
- Figure 6B is a bottom view of the cooling assembly 600, according to the embodiment of Figure 6A.
- the cooling assembly 600 can be used too rapidly cool the deposition material 75 when processing is completed or stopped.
- the cooling assembly 600 includes the cooling plate 602 and the one or more cooling tubes 604 described above.
- the cooling plate 602 may be formed of a material having high thermal conductivity, such as copper or nickel-coated copper.
- the nickel coating can help prevent corrosion of the copper caused by potential exposure to the deposition material 75, such as selenium.
- other materials may be used to form the cooling plate 602, such as stainless steel or molybdenum.
- the cooling plate 602 may have a thickness in the vertical direction (i.e., the Z-direction in Figure 6A) from about 4 mm to about 100 mm, such as 6 mm.
- the cooling plate 602 can have a rectangular shape with a first end 61 1 , a second end 612, a first side 613, and a second side 614.
- the first end 61 1 may be separated from the second end 612 by a length of the cooling plate 602.
- the first side 613 may be separated from the second side 614 by a width of the cooling plate 602.
- the length (Y- direction) and width (X-direction) of the cooling plate 602 can be longer than the corresponding length and width of the crucible base 203 (see e.g., Figure 2A), such as by about 8 mm.
- the crucible 201 can rest on a top surface 605 of the cooling plate 602.
- the top surface 605 of the cooling plate 602 may be flat.
- a sheet 616 (see Figure 1 B) of material having a high thermal conductivity, such as graphite, may be disposed between the cooling plate 602 and the base 203 of the crucible 201 to further promote cooling of the crucible 201 .
- the one or more cooling tubes 604 can be disposed in one or more grooves 608 of a lower surface 606 of the cooling plate 602. Each of the one or more cooling tubes 604 can have a supply 617 for receiving coolant and a return 618 for sending coolant back to the cooling source (not shown).
- the one or more cooling tubes 604 can have a diameter from about 4 mm to about 20 mm, such as about 6 mm.
- the one or more grooves 608 can be sized according to the size of the one or more cooling tubes 604.
- the one or more cooling tubes 604 can be formed of a material having a high thermal conductivity, such as copper or nickel-coated copper.
- the one or more cooling tubes 604 can extend from the first end 61 1 towards the second end 612 in a looped pattern across the lower surface 606 of the cooling plate 602.
- the cooling tube 604 shown in figure 6B shows two loops, each loop covering most of the length of the cooling plate 602 and about half of the width of the cooling plate 602.
- Other embodiments may include cooling tubes 604 having more or less loops.
- Different cooling fluids may be distributed through the cooling tubes 604 to promote cooling of the crucible 201 and the deposition material 75.
- the cooling tube 604 is connected through a three-way valve (not shown) outside of the vacuum chamber 1 1 (see figure 1A) enabling the different cooling fluids or no cooling fluid to be supplied to the cooling tube 604.
- a different cooling fluid is supplied to the cooling tube 604 based on the temperature of the cooling plate 602 or the interior region 204 of the crucible 201 as measured by a thermal sensor, such as thermal sensor 250 described above. For example, during a deposition no cooling fluid may be supplied to the cooling tube 604, for example if no cooling is desired.
- One or more of the valves (not shown) connected to the cooling tube 604 may be opened at this time to prevent an excessive pressure increase inside the cooling tube 604 when the crucible 201 is heated.
- a high temperature of the deposition material 75 such as a temperature greater than 200°C
- a cooling gas such as air
- a cooling liquid such as cooling water
- Cooling water is not supplied to the cooling tube 604 when the measured temperature is greater than 200°C because the high temperature may cause formation of large amounts of steam that could damage the cooling tube 604.
- the cooling plate 602 includes a plurality of tabs 610 mounted (e.g., screwed) to the one or more of the sides of the cooling plate 602, such as the first end 61 1 , the second end 612, the first side 613, and the second side 614.
- Figure 6B shows six tabs 610 mounted to the cooling plate 602 with one tab 610 mounted to either end 61 1 , 612 and two tabs 610 mounted to either side 613, 614.
- the plurality of tabs 610 can help to align the crucible assembly 200 on the cooling plate 602 between the tabs 610.
- the tabs 610 can have a thickness in a direction towards the side of the cooling plate 602 to which the tab 610 is mounted of about 1 mm to about 10 mm, such as about 3 mm.
- part of the crucible assembly 200 may be positioned above and/or outside of the tabs 610.
- the heater clamps described above may be positioned outside of the tabs 610.
- the leg assembly 800 can connect the cooling assembly 600 to the floor of the vacuum chamber 1 1 (see Figure 1A) and support the weight of the cooling assembly 600 and components that are supported by the cooling assembly 600, such as the crucible assembly 200 and the deposition material 75.
- the cooling assembly 600 can rapidly cool the deposition material 75 when processing is completed or stopped as well as for temperature regulation during processing.
- the deposition material 75 may take several hours to cool down to a temperature at which the vacuum chamber 1 1 can safely be vented to atmosphere so that maintenance or other operations can be performed.
- rapid cooling of the deposition material 75 prevents unnecessary evaporation of deposition material 75 that is wasteful.
- additional maintenance may be required to remove the material. For example, condensing deposition material can occur on the openings 402 of the sheets 404 of the lid assembly, which can require additional maintenance.
- FIG 7A is a perspective view of the heat shield assembly 700, according to one embodiment.
- the heat shield assembly 700 includes the one or more side wall portions 710, the one or more base portions 720, and the lid portion 730.
- the one or more side wall portions 710 can be disposed around the thermal isolation assembly 500.
- the one or more materials used for the side wall portions 710 can be chosen to be chemically compatible with the material evaporated by the evaporation source 100, and such materials can include stainless steel and molybdenum as these materials pose a low risk of contaminating the evaporation process.
- the one or more base portions 720 can be disposed below the cooling assembly 600.
- the lid portion 730 can be disposed above the top plate 504 (see Figure 5) of the thermal isolation assembly 500.
- the lid portion 730 may be supported by the one or more side wall portions 710.
- the heat shield assembly 700 may be supported by the leg assembly 800 described above.
- Each portion 710, 720, 730 can be formed of a highly reflective and heat-resistant material, such as molybdenum.
- each portion 710, 720, 730 can include two or more sheets of the highly reflective, heat-resistant material, such as molybdenum.
- Figure 7A shows that the lid portion 730 includes a first sheet 731 disposed on top of a second sheet 732. The sheets 731 , 732 may be cut and then folded before placing the first sheet 731 over the second sheet 732.
- each portion 710, 720, 730 includes two or more sheets
- the sheets may have a thickness from about 0.1 mm to about 1 .0 mm, such as about 0.2 mm.
- One or more of the sheets (i.e., sheets in the portions 710, 720, 730) in these embodiments may include bumps 716 (see Figure 7B) to maintain a spacing between the sheets or different portions of the sheets, such as a spacing from about 0.5 mm to about 3.0 mm.
- the side wall portions 710 can be spaced apart from the thermal isolation assembly 500 by about 4 mm to about 100 mm, such as by about 5 mm.
- the side wall portions 710 can be spaced apart from the cooling tubes 520 of the thermal isolation assembly 500 by about 4 mm to about 100 mm.
- the lid portion 730 can be spaced apart from the thermal isolation assembly 500 by about 2 mm to about 100 mm, such as by about 3 mm.
- the lid portion 730 can include an opening 735 overlying the opening 208 of the top 206 of the crucible 201 .
- the opening 735 can be substantially the same size as the opening 208 of the top 206 of the crucible 201 .
- the opening 735 can be aligned with the opening 208 such that the opening 735 overlies substantially all of the opening 208.
- Figure 7B is a perspective sectional view of a side wall portion 710 and a portion of the frame 740 of the heat shield assembly 700, according to one embodiment.
- Figure 7C is a close-up sectional view of a portion of Figure 7B, according to one embodiment.
- the frame 740 may have a rectangular shape that can surround the thermal isolation assembly 500 (see Figure 1 B).
- the frame 740 may be positioned horizontally at a top 715 of the sidewall portions 710.
- the frame 740 may be formed of stainless steel.
- the frame 740 may include a plurality of internal threads (not shown) for receiving a threaded portion of one of the legs 810 of the leg assembly 800 described above, so that the heat shield assembly may be supported by the leg assembly 800.
- Each side wall portion 710 can be formed of one sheet, such as a molybdenum sheet, folded over the frame 740.
- the side wall portion 710 folded over the frame 740 can include an outer section 71 1 disposed outside of the frame 740 and inner section 712 disposed inside the frame 740.
- the top 715 of the side wall portion 710 is disposed above the frame 740.
- the side wall portion 710 can include a ledge 714 extending inwardly from a bottom 718 of the outer section 71 1 .
- the ledge 714 can be used to support the base portion 720 (see Figure 7D) of the heat shield assembly 700.
- the ledge 714 is disposed at a vertical location spaced apart from a closest part of the cooling assembly 600, such as one of the cooling tubes 604, by about 2 mm to about 100 mm, such as by about 5 mm.
- At least one of the outer section 71 1 and the inner section 712 includes the bumps 716 described above, so that a spacing is maintained between the outer section 71 1 and the inner section 712, such as a spacing from about 0.5 mm to about 3.0 mm.
- the bumps 716 can have a similar shape to the bumps 406 on the sheets 404 of the lid assembly 400.
- each bump 716 can have a cross section that narrows as the bump 716 extends away from the outer section 71 1 or the inner section 712.
- bumps 716 with a cross section that narrows as the bumps 716 extends away from the outer section 71 1 or the inner section 712 reduces the amount of surface area contact between the outer section 71 1 and the inner section 712, which reduces the heat transfer between the outer section 71 1 and the inner section 712.
- Figure 7D is a perspective sectional view of the base portion 720 of the heat shield assembly 700, according to one embodiment.
- the base portion 720 can rest on the ledge 714 of the side wall portions 710 described above.
- the base portion 720 can include a first portion 721 and a second portion 722.
- the first portion 721 can include a first sheet 721 A and a second sheet 721 B.
- the second portion 722 can include a first sheet 722A and a second sheet 722B. At least part of the first portion 721 can overlap part of the second portion 722. Having the first portion 721 overlap the second portion 722 allows for easy removal of one or more of the first portion 721 and the second portion 722 for maintenance or other purposes.
- the first portion 721 and the second portion 722 may each include a plurality of passages 725 to allow a component of the evaporation source 100 to be routed to areas inside the side wall portions 710.
- upper elements 81 1 of the legs 810 may be routed through the passages 725.
- wires for sensors such as the thermal sensor 250 described above, may be routed through the passages 725.
- portions of the cooling tubes 520 and 604 may be routed through the passages 725.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physical Vapour Deposition (AREA)
Abstract
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP17157219 | 2017-02-21 | ||
PCT/EP2018/054137 WO2018153851A1 (fr) | 2017-02-21 | 2018-02-20 | Source d'évaporation avec ensemble d'isolation thermique |
Publications (1)
Publication Number | Publication Date |
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EP3585920A1 true EP3585920A1 (fr) | 2020-01-01 |
Family
ID=58227906
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP18705006.7A Pending EP3585920A1 (fr) | 2017-02-21 | 2018-02-20 | Source d'évaporation avec ensemble d'isolation thermique |
Country Status (2)
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EP (1) | EP3585920A1 (fr) |
WO (1) | WO2018153851A1 (fr) |
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WO2024091392A1 (fr) * | 2022-10-24 | 2024-05-02 | Applied Materials, Inc. | Conception d'évaporateur à faibles charges thermiques |
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TWI624554B (zh) * | 2015-08-21 | 2018-05-21 | 弗里松股份有限公司 | 蒸發源 |
-
2018
- 2018-02-20 WO PCT/EP2018/054137 patent/WO2018153851A1/fr unknown
- 2018-02-20 EP EP18705006.7A patent/EP3585920A1/fr active Pending
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WO2018153851A1 (fr) | 2018-08-30 |
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