Molybdenum sputtering targets

Abstract

Molybdenum, sputtering targets and sintering characterized as having no or minimal texture banding or through thickness gradient. The molybdenum sputtering targets having a fine, uniform grain size as well as uniform texture, are high purity and can be micro-alloyed to improved performance. The sputtering targets can be round discs, square, rectangular or tubular and can be sputtered to form thin films on substrates. By using a segment-forming method, the size of the sputtering target can be up to 6 m×5.5 m. The thin films can be used in electronic components such as Thin Film Transistor—Liquid Crystal Displays, Plasma Display Panels, Organic Light Emitting Diodes, Inorganic Light Emitting Diode Displays, Field Emission Displays, solar cells, sensors, semiconductor devices, and gate device for CMOS (complementary metal oxide semiconductor) with tunable work functions.

1 . A molybdenum sputtering target having fine, uniform grain size as well as uniform texture substantially free of both texture banding and through thickness gradient from a center to an edge of the target, with high purity and optionally micro-alloyed for improved performance.  
     
     
         2 . The molybdenum sputtering target as defined in  claim 1 , having a purity of at least 99.95%.  
     
     
         3 . The molybdenum sputtering target as defined in  claim 1 , having a purity of at least 99.99%.  
     
     
         4 . The molybdenum sputtering target as defined in  claim 1 , having a purity of at least 99.999%.  
     
     
         5 . The molybdenum sputtering target as defined in  claim 1 , wherein the fine, uniform average grain size is not more than 125 μm.  
     
     
         6 . The molybdenum sputtering target as defined in  claim 1 , wherein the fine, uniform average grain size is not more than 100 μm.  
     
     
         7 . The molybdenum sputtering target as defined in  claim 1 , wherein the fine, uniform average grain size is not more than 90 μm.  
     
     
         8 . The molybdenum sputtering target as defined in  claim 1 , wherein the fine, uniform average grain size is not more than 50 μm.  
     
     
         9 . The molybdenum sputtering target according to  claim 1  which has been microalloyed by addition of from 10 ppm to 1,000 ppm of added clement(s).  
     
     
         10 . The microalloyed molybdenum sputtering target according to  claim 9 , wherein the added element(s) include one or more metallic materials selected from elements having a body-centered cubic (BCC) structure.  
     
     
         11 . The microalloyed molybdenum sputtering target according to  claim 9 , wherein the added element(s) include one or more metallic materials selected from the group consisting of Ta, Nb, Cr, W, V and combination thereof.  
     
     
         12 . The molybdenum sputtering target according to  claim 1 , having a shape selected from tubular, round, square, and rectangular.  
     
     
         13 . The microalloyed molybdenum sputtering target according to  claim 9 , having a shape selected from tubular, round, square, and rectangular.  
     
     
         14 . A tubular-shaped sputtering target formed by: 
 A) placing molybdenum powder in a mold and pressing the powder at a pressure of from 32 to 40 ksi and sintering the pressed piece at a temperature of from 1785 to 2175° C. to form abillet;    B) removing the center of the billet to form a tubular billet having an inner diameter ID I  and an outer diameter OD I ;    C) working the tubular billet to form a worked billet having an inner diameter ID and an outer diameter OD f  such that the ratio of OD I  to OD f  is at least 3:1; and    D) heat treating the tubular billet at a temperature of from 815 to 1375° C.    
     
     
         15 . The sputtering target according to  claim 14 , wherein the pressing in A) is performed isostatically.  
     
     
         16 . The sputtering target according to  claim 14 , wherein the powder in A) is sintered in hydrogen.  
     
     
         17 . The sputtering target according to  claim 14 , wherein ID is greater than ID I .  
     
     
         18 . The sputtering target according to  claim 14 , wherein the working in C) comprises extruding the tubular billet at a temperature of from 925 to 1260° C.  
     
     
         19 . The sputtering target according to  claim 14 , wherein the working in C) comprises rotary forging the tubular billet.  
     
     
         20 . The sputtering target according to  claim 14 , wherein after heat treating in D), the sputtering target is completely recrystallized and strain-free.  
     
     
         21 . The sputtering target according to  claim 14 , wherein the texture is uniform and 110 parallel to the longitudinal direction and 111 relative to the radial direction.  
     
     
         22 . The sputtering target according to  claim 14 , wherein the heat treatment in D) is carried out at from 1250 to 1375° C.  
     
     
         23 . The sputtering target according to  claim 14 , wherein the heat treatment in D) is carried out at from 815 to 960° C.  
     
     
         24 . A tubular-shaped sputtering target comprising molybdenum having a uniform texture, which is a 110 orientation parallel to the longitudinal direction and a 111 orientation relative to the radial direction.  
     
     
         25 . A method of making a tubular sputtering target comprising: 
 A) placing molybdenum powder in a mold and pressing the powder at a pressure of from 32 to 40 ksi and sintering the pressed piece at a temperature of from 1785 to 2175° C. to form a billet;    B) removing the center of the billet to form a tubular billet having an inner diameter ID I  and an outer diameter OD I ;    C) working the tubular billet to form a worked billet having an inner diameter ID and an outer diameter OD f  such that the ratio of OD I  to OD f  is at least 3:1; and    D) heat treating the tubular billet at a temperature of from 815 to 1375° C.    
     
     
         26 . The method target according to  claim 25 , wherein the pressing in A) is performed isostatically.  
     
     
         27 . The method according to  claim 25 , wherein the powder in A) is sintered in hydrogen.  
     
     
         28 . The method according to  claim 25 , wherein the working in C) comprises extruding the tubular billet at a temperature of from 925 to 1260° C.  
     
     
         29 . The method according to  claim 25 , wherein the working in C) comprises rotary forging the tubular billet.  
     
     
         30 . The method according to  claim 25 , wherein after heat treating in D), the sputtering target is completely recrystallized and strain-free.  
     
     
         31 . The method according to  claim 25 , wherein the sputtering target texture is uniform and 110 parallel to the longitudinal direction and 111 relative to the radial direction.  
     
     
         32 . The method according to  claim 25 , wherein the heat treatment in D) is carried out at from 1250 to 1375° C.  
     
     
         33 . The method according to  claim 25 , wherein the heat treatment in D) is carried out at from 815 to 960° C.  
     
     
         34 . A sputtering target made according to the method of  claim 25 .  
     
     
         35 . A method of sputtering, comprising subjecting the sputtering target of  claim 1  to sputtering conditions and thereby sputtering the target.  
     
     
         36 . The method of  claim 35 , wherein the sputtering is done using a sputtering method selected from the group consisting of magnetron sputtering, pulse laser sputtering, ion beam sputtering, triode sputtering, and combinations thereof.  
     
     
         37 . A method of sputtering, comprising subjecting the sputtering target of  claim 34  to sputtering conditions and thereby sputtering the target.  
     
     
         38 . The method of  claim 37 , wherein the sputtering is done using a sputtering method selected from the group consisting of magnetron sputtering, pulse laser sputtering, ion beam sputtering, triode sputtering, and combinations thereof.  
     
     
         39 . A method for making a thin film, comprising the steps of: 
 (a) sputtering the sputtering target according to  claim 1;     (b) removing Mo atoms from the target; and    (c) forming a thin film comprising molybdenum onto a substrate.    
     
     
         40 . The method according to  claim 39 , further comprising the step, after (b) of supplying a reactive gas to the Mo.  
     
     
         41 . The method according to  claim 39 , wherein the reactive gas is oxygen, nitrogen and/or a silicon containing gas.  
     
     
         42 . The method of  claim 39 , wherein the thin film has a thickness ranging from 0.5 nm to 10 μm.  
     
     
         43 . The method of  claim 39 , wherein the sputtering method is selected from the group consisting of magnetron sputtering, pulse laser sputtering, ion beam sputtering, triode sputtering, and combinations thereof.  
     
     
         44 . A thin film made in accordance with the method of  claim 39 .  
     
     
         45 . A thin film made in according with the method of  claim 41 , wherein the films have a composition comprising MoO x  (oxidation), MoN x  (nitridation), or MoSi x  (silicidation) and combinations thereof, produced by reactive sputtering with oxygen, nitrogen or silicon atoms or by ion implantation.  
     
     
         46 . A flat panel display device comprising the thin film according to  claim 44 .  
     
     
         47 . The flat panel device according to  claim 46 , wherein the device is selected from the group consisting of Thin Film Transistor—Liquid Crystal Displays, Plasma Display Panels, Organic Light Emitting Diodes, Inorganic Light Emitting Diode Displays, and Field Emission Displays.  
     
     
         48 . The sputtering target according to  claim 14 , having an average grain size of not more than 125 μm.  
     
     
         49 . A disc-shaped sputtering target formed by: 
 I) placing molybdenum powder in a mold and pressing the powder at a pressure of from 200 MPa to 250 MPa and sintering the pressed piece at a temperature of from 1780 to 2175° C. to form a billet having a diameter of D o ;    II) extruding the billet to form an extruded billet having a diameter of D 2  such that the ratio of D o  to D 2  is from 3:1 to 5:1;    III) applying a first heat treatment to the extruded billet at a temperature of from 900 to 1300° C.;    IV) upset forging the extruded billet at a temperature of from 870 to 1200° C. to form a forged billet having a diameter D f  such that the ratio of D f  to D 2  is from 1.5:1 to 3:1; and    V) applying a second heat treatment to the forged billet at a temperature of from 1200 to 1400° C.    
     
     
         50 . The sputtering target according to  claim 49 , wherein the pressing in A) is performed isostatically.  
     
     
         51 . The sputtering target according to  claim 49 , wherein the molybdenum powder is obtained by reduction of ammonium dimolybdate in hydrogen.  
     
     
         52 . The sputtering target according to  claim 51 , wherein the ammonium dimolybdate is at least 99.9 wt.% pure.  
     
     
         53 . The sputtering target according to  claim 49 , wherein after the second heat treating in E), the sputtering target is completely recrystallized and strain free.  
     
     
         54 . The sputtering target according to  claim 49 , wherein after E), a disc-shaped portion is cut from the heat-treated forged billet to provide a disc-shaped sputtering target.  
     
     
         55 . A method of making a sputtering target comprising: 
 I) placing molybdenum powder in a mold and pressing the powder at a pressure of from 200 MPa to 250 MPa ksi and sintering the pressed piece at a temperature of from 1780 to 2175° C. to form a billet having a diameter of D o ;    II) extruding the billet to form an extruded billet having a diameter of D 2  such that the ratio of D o  to D 2  is from 3:1 to 5:1;    III) applying a first heat treatment to the extruded billet at a temperature of from 900 to 1300° C.;    IV) upset forging the extruded billet at a temperature of from 870 to 1200° C. to form a forged billet having a diameter D f  such that the ratio of D f  to D 2  is from 1.5:1 to 3:1; and    V) applying a second heat treatment to the forged billet at a temperature of from 1200 to 1400° C.    
     
     
         56 . The method according to  claim 55 , wherein the pressing in A) is performed isostatically.  
     
     
         57 . The method according to  claim 55 , wherein the powder in A) is sintered in hydrogen.  
     
     
         58 . The method according to  claim 55 , wherein the molybdenum powder is obtained by reduction of ammonium dimolybdate in hydrogen.  
     
     
         59 . The method according to  claim 58 , wherein the ammonium dimolybdate is at least 99 wt. % pure.  
     
     
         60 . The method according to  claim 55 , wherein after heat treating in E), the sputtering target is completely recrystallized and strain free.  
     
     
         61 . The method according to  claim 55 , further comprising the step 
 VI) cutting a disc-shaped portion from the heat-treated forged billet to provide a disc-shaped sputtering target.    
     
     
         62 . A sputtering target made according to the method of  claim 55 .  
     
     
         63 . A method of sputtering, comprising subjecting the sputtering target of  claim 48  to sputtering conditions and thereby sputtering the target.  
     
     
         64 . The method of  claim 63 , wherein the sputtering is done using a sputtering method selected from the group consisting of magnetron sputtering, pulse laser sputtering, ion beam sputtering, triode sputtering, and combinations thereof.  
     
     
         65 . A method of sputtering, comprising subjecting the sputtering target of  claim 62  to sputtering conditions and thereby sputtering the target.  
     
     
         66 . The method of  claim 65 , wherein the sputtering is done using a sputtering method selected from the group consisting of magnetron sputtering, pulse laser sputtering, ion beam sputtering, triode sputtering, and combinations thereof.  
     
     
         67 . A method for making a thin film, comprising the steps of: 
 (a) sputtering the sputtering target according to  claim 49;     (b) removing Mo atoms from the target; and    (c) forming a thin film comprising molybdenum onto a substrate.    
     
     
         68 . The method according to  claim 67 , further comprising the step, after (b) of supplying a reactive gas to the Mo.  
     
     
         69 . The method according to  claim 68 , wherein the reactive gas is oxygen, nitrogen and/or a silicon containing gas.  
     
     
         70 . The method of  claim 67 , wherein the thin film has a thickness ranging from 0.5 nm to 10 μm.  
     
     
         71 . The method of  claim 67 , wherein the sputtering method is selected from the group consisting of magnetron sputtering, pulse laser sputtering, ion beam sputtering, triode sputtering, and combinations thereof.  
     
     
         72 . A thin film made in accordance with the method of  claim 67 .  
     
     
         73 . A thin film made in according with the method of  claim 69 , where the film comprises one or more of MoO x , MoN x , or MoSi x , wherein the film is produced by reactive sputtering with oxygen, nitrogen or silicon atoms or by ion implantation.  
     
     
         74 . The sputtering target according to  claim 49 , having an average grain size of not more than 65 μm.  
     
     
         75 . Large molybdenum plates having a non-segmented construction, weighing at least 300 kg, and comprising at least 99% by weight of molybdenum.  
     
     
         76 . The plate according to  claim 75 , wherein the plate has a fine, uniform grain size of not more than 100 μm.  
     
     
         77 . The plate according to  claim 75 , wherein the plate has a texture that is substantially free of banding and substantially free of any through thickness gradient.  
     
     
         78 . The plates according to  claim 75 , having a rectangular cross sectional shape and having a length of from 0.8 to 4.0 m, a width of from 0.7 to 2.5 m and a height of from 0.008 to 0.064 m.  
     
     
         79 . The plates according to  claim 75 , having a square cross sectional shape and having a length of from 0.8 to 3.0 m, a substantially equal width and height of from 0.008 to 0.064 m.  
     
     
         80 . The plates according to  claim 75 , cut to form a cylindrical cross section and having a diameter of from 0.7 to 3 m and a height of from 0.008 to 0.064 m.  
     
     
         81 . A process for preparing the plate according to  claim 75 , comprising: 
 i) pouring molybdenum powder into a sheet bar mold; 
 a. consolidating the powder by cold isostatic pressing (C.I.P.) at a pressures of from 100 to 250 MPa (15 to 36 ksi) to form a sheet bar;  
 b. sintering the sheet bar at a temperature of at least 1600° C. to form an ingot having a density of at least 90% of the theoretical density;  
   ii) preheating the ingot at a temperature of from 1100 to 1450° C.; 
 a. hot rolling the ingot at a temperature of from 1050° to 1400° C. to effect a reduction in the thickness and an increase in the length of the ingot;  
   iii) heat treating the rolled ingot at a temperature of from 850 to 950° C.    
     
     
         82 . The process according to  claim 81 , wherein the powder has a molybdenum purity of greater than 99.9%.  
     
     
         83 . The process according to  claim 81 , wherein the powder is produced from reduction of ammonium dimolybdate in hydrogen.  
     
     
         84 . The process according to  claim 81 , wherein the thickness reduction in v) provides an ingot with a height of from 0.060 to 0.140 percent of the height of the sheet bar.  
     
     
         85 . The process according to  claim 81 , wherein the hot rolling step reduces the thickness of the ingot by successive rolling reduction.  
     
     
         86 . The process according to  claim 81 , further comprising the step of inspecting the integrity of the ingot with ultrasonic techniques.  
     
     
         87 . The process according to  claim 81 , further comprising the step of precision leveling the ingot to achieve the optimum flatness for the machining/grinding operations to the final dimensions.  
     
     
         88 . A sputtering target comprising a portion of the molybdenum plate made according to  claim 75 .  
     
     
         89 . A method of sputtering, comprising subjecting the sputtering target of  claim 88  to sputtering conditions and thereby sputtering the target.  
     
     
         90 . The method of  claim 89 , wherein the sputtering is done using a sputtering method selected from the group consisting of magnetron sputtering, pulse laser sputtering, ion beam sputtering, triode sputtering, and combinations thereof.  
     
     
         91 . A method for making a thin film comprising the steps of: 
 (a) sputtering the sputtering target according to  claim 85;     (b) removing Mo atoms from the target; and    (c) forming a thin film comprising molybdenum onto a substrate.    
     
     
         92 . The method according to  claim 91 , further comprising the step, after (b) of supplying a reactive gas to the Mo.  
     
     
         93 . The method according to  claim 92 , wherein the reactive gas is oxygen, nitrogen and/or a silicon containing gas.  
     
     
         94 . The method of  claim 91 , wherein the thin film has a thickness ranging from 0.5 nm to 10 μm.  
     
     
         95 . The method of  claim 91 , wherein the sputtering method is selected from the group consisting of magnetron sputtering, pulse laser sputtering, ion beam sputtering, triode sputtering, and combinations thereof.  
     
     
         96 . A thin film made in accordance with the method of  claim 91 .  
     
     
         97 . A thin film made in according with the method of  claim 93 , wherein the film comprises one or more of MoO x , MoN x , and MoSi x , wherein the film is produced by reactive sputtering with oxygen, nitrogen or silicon atoms or by ion implantation.  
     
     
         98 . A device comprising the thin film according to  claim 96 .  
     
     
         99 . The device according to  claim 98 , wherein the device is selected from the group consisting of Thin Film Transistor—Liquid Crystal Displays, Plasma Display Panels, Organic Light Emitting Diodes, Inorganic Light Emitting Diode Displays, Field Emission Displays, solar cells, gas sensors, and semiconductor devices.  
     
     
         100 . A device comprising the thin film according to  claim 97 .  
     
     
         101 . The device according to  claim 100 , wherein the device is selected from the group consisting of Thin Film Transistor—Liquid Crystal Displays, Plasma Display Panels, Organic Light Emitting Diodes, Inorganic Light Emitting Diode Displays, Field Emission Displays, solar cells, gas sensors, and semiconductor devices.  
     
     
         102 . The thin film according to  claim 96 , wherein a segment-forming sputtering target is used.  
     
     
         103 . The method according to  claim 89 , wherein the size of the sputtering target is up to 6 m by 5.5 m.  
     
     
         104 . The thin film of  claim 4 , wherein the thin film thickness ranges from 100 Å to 5,000 Å.  
     
     
         105 . The thin film according to  claim 44 , wherein the film has a work function of from 4.5 to 6 eV depending on nitrogen content.  
     
     
         106 . The device according to  claim 98 , wherein the thin film is deposited over a plastic substrate comprising one or more plastics selected from the group consisting of polynorbornene, polyimide, polyarylate, polycarbonate, polyethylenenaphthanate, and polyethyleneterephthalate.  
     
     
         107 . The device according to  claim 98 , wherein the thin film is disposed over at least a portion of a ceramic substrate comprising sapphire and/or quartz.  
     
     
         108 . Electronic components comprising the thin film according to  claim 44 .  
     
     
         109 . The electronic components of  claim 108 , wherein the components are selected from the group consisting of thin film transistors (TFT), Liquid Crystal Displays (TFT-LCD), Plasma Display Panels (PDP), Organic Light Emitting Diodes (OLED), Inorganic Light Emitting Diode Displays (LED), Field Emission Displays (FED), semiconductor devices, solar cells, sensors, black matrix devices to enhance image contrast of Flat Panel Displays, solar cells, sensors, and gate device for CMOS technology (complementary metal oxide semiconductor) with tunable work function.  
     
     
         110 . The sputtering target according to  claim 49 , wherein the powder in A) is sintered in hydrogen.