NanoFoil Technology: Formation Reactions & Thermite Reactions

Transcription

1 NanoBond : Target Bonding for Optimum Sputtering Performance Alan Duckham Reactive NanoTechnologies Reactive NanoTechnologies, Inc. (RNT) 111 Lake Front Drive Hunt Valley, MD (p) (f) AIMCAL Fall Technical Conference October 10, 2007

2 NanoFoil Technology: Formation Reactions & Thermite Reactions Ni (NanoFoil ) Al Initial Reactants: Al and Ni layers (micro or nano thick) Final Product: Al-Ni Intermetallic 2

3 NanoFoil Applications Joining Applications Large Area Joining of Dissimilar Materials Sputter targets Ceramic-metal joining armor mounting Power Amp LED attach Large area joining Microelectronics Applications Thermal interface material Packaged part attach Power-amplifier Connector mounting 3

4 Conventional Soldering or Brazing Different materials shrink at a different rates Large thermal stresses when joining dissimilar materials using furnaces or hot plates Room Temperature Solder: 220 ºC Braze: 700 ºC Room Temperature 4

5 Joining with NanoFoil (NanoBond) Heat only the interface Use any solder and some brazes Rapid, room temperature process Metallized or Prewet Surfaces 5

6 Bonding Sputter Targets by NanoBond 56 x 10 TiC to Ti 50 x6 ITO to Cu 40 x10 Glass to CU 6

7 Modeling Heat Transfer during NanoBond Energy Conservation in each layer h r = Ñ q + Q& t Braze Layer NanoFoilTM Ti-6-4 Plate Braze Layer Inputs SiC Plate Foil reaction properties Materials properties Material geometries Interface resistances x 7

8 Temperature ( C) Predicted Thermal Profiles: SiC/Ti t=0 Braze layers Reactive Foil Ti-6-4 SiC (6.7 W/mK) (110 W/mK) x (mm) 8

9 Predicted Thermal Profiles: SiC/Ti 1500 Braze layers t = 7 ms Temperature ( C) Ti-6-4 SiC 700 (6.7 W/mK) (110 W/mK) x (mm) 9

10 Predicted Thermal Profiles: ITO to CU 10

11 Case Study: SiC/Ti-6-4 SiC Plate Braze Layer (40µm) 100µm Reacting Foil IR Camera Braze Layer (40µm) Ti-6-4 Plate 11

12 IR Imaging of Reaction K = 80 W/m-K SiC K = 6.7 W/m-K Ti

13 IR Imaging of Reaction Images spaced at 140msec 13

14 Modeling of Dissimilar CTE System (2D) ITO Cu Deflection and Residual Stress significantly lower with NanoBond 14

15 Properties of Sputtering Targets bonded by NanoBond Elastomer Indium SnAg NanoBond Thermal Conductivity (W/mK) Electrical Conductivity (106S/m) Shear Strength (psi) Vapor Pressure (Torr) Less than 1% Torr for 24 hr) 487 ºC 597 ºC 742 ºC 682 ºC 807 ºC 997 ºC Temperature Limit (ºC) Thermal Shock Bond Coverage Survived MIL-STD810: Cycle between -51 ºC and 71 ºC % 15

16 Bond Inspection Destructive Strength testing Typical shear strengths = 25 MPa (3600 psi) Cross-sectional microscopy 16

17 Bond Inspection Non Destructive Ultrasonic scanning of bond interface to check for void content Void content of < 2 % is typical 17

18 Case Study Alumina Elastomer NanoBond Elastomer Bonds: Cracked at 300W, Pieces Fell off at 400 W NanoBond: Very Stable at 400 W, Ramped to 500W, Not run to Failure 18

19 Case Study B4C Indium Bonded NanoBond 4 tile array to Cu: 25 x 6 Vertical cracks after brief 2kW sputtering and debonding on corners No cracks after 4kW sputtering for 20 cycles and >200hrs total operation 19

20 Comparison Study Targets bonded to indirect cooled Cu B/Ps Target Material Power Mode Bond Type Max. Power without Failure (W) Power at Failure (W) ITO DC Elastomer ITO DC InSn-Reflow ITO DC In Reflow 325 (1 Hour) 425 ITO DC NanoBond 460 (12 hours) 540 Alumina RF Elastomer Alumina RF NanoBond 400 Not Run to Failure Quartz RF NanoBond 400 Not Run to Failure TiC DC NanoBond TiC DC Braze NanoBond 1600 (Stable) Not Run to Failure Si DC NanoBond Significantly better performance than elastomer and reflow joints 20

21 Power Dependency on Solder Melting Temperature 21

22 Stresses During Sputtering Al2O3 bonded to Cu 22

23 Stresses During Sputtering Al2O3 bonded to Cu Average Temp. in Target (ºC) 50.1 Average Temp. in B/P (ºC) 31.3 Expansion of Target (ppm) 208 Expansion of B/P (ppm) 158 Stress in Target (MPa) 6 (compressive) Unconstrained expansion 23

24 Braze NanoBond of Sputtering Targets New process to replace diffusion bonding Ultra high strengths and temperature limits Trials on 4 in diameter targets Al to Al: 100 % coverage Cu to Cu: 100 % coverage W to Brass: >99 % coverage Scaling up process to 18 in diameter targets 24

25 Summary NanoBond is a substitute for Indium, Pb-Sn and Elastomer Bonds Significantly lower residual stress and deflection on components Increased throughput Higher Strength, Reliability Good Thermal and Electrical Conduction (No Arcing) Improved bond line, thickness, flatness control compared to conventional process Compatible with any solder: SnAg most often used Process proved on a number of commercial applications (All metals, Si, Ge, Oxides - incl. ITO, SiO2, Al2O3, Carbides and Nitrides) Process demonstrated on joints up to 750 Sq in with no known size limitation Braze NanoBond under development 25