Micro/Nano Solids Word Scramble
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| Question | Answer |
| Describe the Oxidation process | Individual atoms from surrounding environment penetrate the surface of the substrate and a thin layer is formed |
| What temperatures do oxidation processes operate at? | 700 degrees |
| Oxidation depends on which rates? | Chemical reaction at the interface, & diffusion of the oxidant through existing oxide layer |
| Types of Chemical Vapour Deposition? | Low Pressure CVD (LPCVD), Plasma Enhanced (PECVD) |
| Physical Deposition (Sputtering) | atoms ejected from a solid due to bombardment, high pressure |
| Physical Deposition (Evaporation) | Metal source heated to melting, atoms transported with the vapor to the substrate, 1nm/min |
| Chemical Deposition Process | Reactant comes to surface, adsorption at surface, reaction, desorption, transport of by product |
| LPCVD Benefits | Control unwanted gas-phase reactions, improve film uniformity,minimise diffusion effects |
| LPCVD Downsides | Can take 3hrs for 15nm, only 3 mins for deposition but the rest for controlling temperature and pressure |
| PECVD Benefits | Faster than LPCVD,Lower temps are good for components with low melting temp. |
| PECVD Downsides | Film quality is not as good |
| Stress in deposited films is caused by | Lattice mismatch, differences in thermal expansion coefficients |
| Photolithography - Preperation before coating | Clean wafer, apply primer, rotate, soft bake, exposure and post bake |
| Photolithography - Exposure Methods | Contact, Proximity, Projection |
| Types of Etching | Physical (plasma etching), Chemical (wet etching) |
| Wet etchant to remove Si isotropically | KOH or TMAH (tetra methyl amonium hydroxide) |
| Wet etchant to remove SiN (but not Si or SiO2) | H3PO4 |
| Isotropically etch SiO2? | HF |
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