Prelab Question What is the benefits of using
Prelab Question What is the benefits of using a 4 point-probe setup rather than a 2 point-probe setup for resistance measurement? 2
金屬鍍膜 (Metal Deposition) o 本實驗使用物理鍍膜 (Physical Vapor Deposition;PVD) o 需在真空下進行 o 可分為蒸鍍(evaporation)與濺鍍 (sputtering)兩種 o 蒸鍍環境: 10 -6~10 -7 Torr 4
o 1 atm= 760 torr= 760 mm. Hg= 101325 Pa=1013. 25 mbar o 1 Torr ≈ 133. 32237 Pa o 1 mbar = 100 Pa = 1 h. Pa = 0. 1 k. Pa o 1 Pa= 1 N/m² = 1(kg·m·s-2)/m² =1(kg·m-1·s-2) 5
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o Mechanical pump https: //www. youtube. com /watch? v=s 3 xul. CRrjos 9
Diffusion pump
Turbo pump
o Bearing式(培林) 14
cryogenic pump
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濺鍍-真空系統 N 2 Ar 2 VENT Chamber GAS VALVE MV RV MP TP FV 27
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4 point probe可以更精確量得V與resistivity 37
Sheet resistance單位定義 Because the bulk resistance is multiplied by a dimensionless quantity to get sheet resistance, the units of sheet resistance are ohms. An alternate, common unit is "ohms per square" (denoted "Ω/sq" or " "), which is dimensionally equal to an ohm, but is exclusively used for sheet resistance. This is an advantage, because a sheet resistance of "1Ω" could be taken out of context and misinterpreted as a bulk resistance of 1 ohm, while a sheet resistance of "1Ω/sq" cannot be so misinterpreted. The reason for the name "ohms per square" is that a square sheet with sheet resistance 1 ohm/square has an actual resistance of 1 ohm, regardless of the size of the square. (For a square, L = W, so RS = R. ) The unit can be thought of as, loosely, "ohms per aspect ratio". 40
考慮各種形狀: F 1: The finite thickness of the sample F 2: The alignment of the probes in the proximity of a sample edge F 3: The finite lateral width of the sample 41
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實驗結果 1. Calculate metal thickness Rsheet=r/tmetal @20 o. C Au Ag Cu Pt Al Ni Ti W Resistivity 2. 44 1. 59 1. 68 10. 6 2. 82 6. 99 42. 0 5. 60 (10 -8 W-m) Fe Pb 10 2. 2 Ref: https: //www. thoughtco. com/table-of-electrical-resistivity-conductivity-608499 量測sheet resistance and resistance 經由resistivity換算得thickness 量測sheet resistance and resistance 經由thickness換算得resistivity 46
結報問題 1. For different gas tanks, what does the color mean? 2. What is a pressure regulator? How does it work? 3. What is the color of the plasma from different gases? 4. How does the ion gauge work? 5. What’s the difference between DC sputtering and RF sputtering? What are they suitable for? 6. Check out the 18 -inch wafer in EE 2 -220. 7. What is SRP? How is the resistivity measured by SRP? 47
Starting from 32 nm node, parasitic resistance dominates o o Ref: Reza Arghavani et al. , in IEDM short course, 2016. (Source: Semiconductor Fabtech, 35 th Edition 2007 IEEE Trans. on Electron Devices, Vol. 55 2008) Parasitic resistance increases with scaling due to S/D and contact area shrinkage. Starting from 32 nm node, parasitic resistance > channel resistance and dominates the transistors performance. Channel resistance is no longer the bottleneck. In order to have performance gain, parasitic resistance must be reduced. Slide 49
Parasitic resistance Ref: H. Wu et al. , in IEDM, 2018, pp. 819 -822. o Parasitic resistance consists of metal resistance (RMETAL), contact resistance (RC), and epi resistance (REPI). o RC and REPI are dominant components of parasitic resistance. Slide 50
ρc < 10 -9 Ω-cm 2 is needed beyond 7 nm node [1] O. Gluschenkov et al. , in IEDM, 2016, pp. 448 -451. [2] 2016 IRDSTM, More Moore, https: //irds. ieee. org/reports. o o o From the TCAD simulation [1], the relationship of RC and ρc is obtained. IRDS roadmap for RC is obtained by assuming that RC = 50% REXT. Intercept of the lines with same color is the target of ρc. 10 nm (red): <7 E-9 Ω-cm 2; 7 nm (blue): <3 E-9 Ω-cm 2 Beyond the 7 nm node, the ρc lower than 1 E-9 Ω-cm 2 is required. Slide 51
Contact Resistivity只跟材料本質有關 跟厚度, W, L無關 52
Transmission Line Method (TLM) Metal semi 忽略Rmetal 與fringing current TLM 54
Rm: metal sheet resistance Rs: Semi sheet resistance refined transmission line model circular transmission line model 4 CTLM • Rm只能用 4點探針下在 metal pad上另外得 • LC要知道 1 RTLM • 製程難 Fitting 得Rs,再以LT得contact resistivity 55
Rm: metal sheet resistance Rs: Semi sheet resistance 讓Rm 比重下降 Multi-Ring CTLM IEEE ELECTRON DEVICE LETTERS, VOL. 36, NO. 6, JUNE 2015 50 m. A~100 m. A V~1 V delta. V=7~20 m. V 56
2019 VLSI 57
nano-TLM 可以得Rm 58
2019 VLSI Ladder TLM 可以得Rm Rshm: metal sheet resistance Rshs: Semi sheet resistance 59
Rmetal Rc Repi 60
Kelvin measurements 61
Summary p業界直接用元件量 Rshm 不能太大 2015 o TLM CTLM RTLM MRCTLM 1972 1980 o Kelvin 1983 2012 把Rshm 影響降到最低 nano-TLM 2014 把Rshm 量出來 Ladder TLM 2019 把Rshm 量出來 62
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