AD occ ltation of Sat rn b J piter 37,628 AD occultation of Saturn by Jupiter 36,774 AD occultation of Saturn by Jupiter 30,121 AD occultation of Saturn by Jupiter 23 350 AD occultation of Saturn by Jupiter 23,350 AD occultation of Saturn by Jupiter 21,303 AD occultation of Saturn by Jupiter 13,738 AD occultation of Saturn by Jupiter 13 340 AD occultation of Saturn by Jupiter 13,340 AD occultation of Saturn by Jupiter 8,674 AD occultation of Saturn by Jupiter 7,541 AD occultation of Saturn by Jupiter (2x within a few months) 19/36
simultaneous transit Venus + Earth seen from Mars 224,508 AD near-simultaneous transit of Venus and Mercury 69,163 AD simultaneous Venus + Mercury transit 38,172 AD transit of Uranus seen from Neptune 15,790 AD simultaneous annular solar eclipse and transit of Mercury 15,232 AD simultaneous total solar eclipse and transit of Venus 13,425 AD near-simultaneous transit of Venus and Mercury 11 575 AD i lt l l li d t it f M 11,575 AD simultaneous annular solar eclipse and transit of Mercury 11,268 AD simultaneous total solar eclipse and transit of Mercury 10,663 AD simultaneous total solar eclipse and transit of Mercury 9 966 AD simultaneous total solar eclipse and transit of Mercury 9,966 AD simultaneous total solar eclipse and transit of Mercury 9,622 AD simultaneous annular solar eclipse and transit of Mercury 9,361 AD simultaneous annular solar eclipse and transit of Mercury 8 059 AD simultaneous annular solar eclipse and transit of Mercury 8,059 AD simultaneous annular solar eclipse and transit of Mercury 6,757 AD simultaneous solar eclipse and transit of Mercury -15,607 BC simultaneous total solar eclipse and transit of Venus -90 109 BC near-simultaneous transit of Venus and Mercury 19/36 90,109 BC near simultaneous transit of Venus and Mercury -373,173 BC simultaneous Venus + Mercury transit
may have evolved into another (similar) one evolved into another (similar) one likelihood nearly 100% Homo sapiens may no longer exist Homo sapiens may no longer exist
What does this say? Answer: Human Document (Old English Runic alphabet, used until 10th century) How can we make our document ( g p , y) Answer: We have to teach our language understandable? Answer: We have to teach our language
using pictures B k f t hi h th h t d ( ith Analyze • Books focus on teaching how the characters sound (with teacher/parental assistance) Problems Children’s books do not teach the meaning of words Need external influences to assist learning Problems Need external influences to assist learning 8/35
d b th d Analyze • Words are described by other words • Often used to help learn other languages Problems • First steps of learning very difficult Problems p g y (excellent as a 2nd step) 9/35
d b i t l Unable to explain all words by pictures alone Inefficient, in terms of coverage Possible solution Ontology: classification of words, and the relationships between h them 11/35
of a master class: 1. Objects that can be easily seen in nature without Master class (2) Master class (1) j y additional tools 2. Objects that might not change significantly even after 1 million years 1 million years 3. Contains threshold hierarchy, e.g. mammal class, bird class Slave class (1.1) Slave class (1.2) Slave class (2.1) Slave class (2.2) 13/35 Slave class (1 1 2)
Slave picture M t l picture which Master classes Unique objects (e.g Sun, Moon) picture which represents a current view of the Earth (e.g Sun, Moon) Exceptions (e.g. cloud, are inside the master i t of the Earth humans, fire) 15/35 pictures
Movement of chip or sand particles Speed & Force rosion Th Shock Occurence of fire Occurence of volcano Maximum temperature Fatigue Daily & annual Difference between maximum We Thermal Fatigue y temperature change and minimum temperature eathering Freezing Ice forming Minimum temperature Pressure Something can fall down over the wafer Applied pressure g Pressure Something can fall down over the wafer or an animal can walk over it Applied pressure Chemical Acid rain Concentration Temperature Chemical Acid rain Hydroxide round biochemical reaction etc Concentration Temperature
(1) p ( ) nozzle chip Problem: Difficult to make a quantitative relation between sand particle Relationship between pressure and destruction velocity and the rate of destruction 21/35
for friction experiment (2) • Two parameters investigated: Effect of grinding speed with constant force (2 N) for 20s Effect of force applied by grinding machine with constant speed (20,000 ) f 20 rpm) for 20 s 22/35
applied force (constant ( p ) ( p ) grinding speed) Depth(µm) A particle moving 1 cm/year with 2 N force would remove 0 2 nm of chip material in 20 seconds 0.2 nm of chip material in 20 seconds Lifetime of a 500um chip would be Applied force (N) Lifetime of a 500um chip would be 1.5 years only !!! Depth = √(Kf × grinding speed) Kf = 590 µm2/N Applied force (N) 24/35 Kf = 590 µm /N
e.g. etching rate of silicon <100> with 20 % KOH at 20 °C is 25.3 nm/min Etching rate of lower concentrations is linear – Etching rate of lower concentrations is linear etching rate = (1.25 X 10-3) Concentration It will take 14,000,000 years to etch a • Ground water is usually slightly alkaline (pH 8) – Natural sources of hydroxide: 500 µm chip Natural sources of hydroxide: 1) Erosion of carbonate-containing “limestone” 2) Leaching from hardwood ashes (e.g. after forest fires) Concentration of ground water =5.61 X 10 -8 26/35
chip (500um thick) S ill d h hi d i h d Example: to break 1 cm chip (500um thick) 4.58 MN is needed 1m deep = 9.6 MN • Silicon hardness Stress will reduce when chips are deeper in the ground 2m deep = 38.3MN 3m deep = 43.1MN 30/35
Not stable enough packaging, resin cover put it underground no thermal problem ion g Th Shock Stable no thermal problem less pressure problem ti l t / f i ti ? Weat hermal Fatigue Stable Freezing Stable particle movement / friction ? put the chip on the moon thering Pressure Not stable enough Ch i l N t t bl h put the chip on the moon thermal problem ? friction problem ? Chemical Not stable enough friction problem ? no pressure problem (nobody there) no chemical problem (no water) 31/35 no chemical problem (no water)
teaching ontology tree used for teaching silicon device needs better layout, splitting into chips, protective coating splitting into chips, protective coating bili i hi h stability tests give hints how to improve lifetime of devices 33/35 p