Electroplating (ECD) Cell

1. Theory

• Definition: An electroplating (ECD) cell deposits copper from an acid copper sulfate bath onto a seeded wafer acting as cathode, with thickness set by charge through Faraday’s law (Monash; Moffat et al.).
• Faraday’s law: Each Cu${}^{2+}$ ion needs two electrons, and one faraday is 96 500 C (Monash).
• Additives: A suppressor (PEG with chloride) slows deposition almost a hundredfold; an accelerator (SPS) restores it locally; levelers adjust the overfill (Moffat et al.; Tang et al.).
• Superfill: Growth velocity follows local accelerator coverage, which rises as concave trench bottoms shrink, so features fill bottom-up (Moffat et al.).
• Terminal effect: A thin seed’s resistance makes the wafer edge plate faster than the centre (Novellus).

2. Working Principle

• Stack: Ta barrier and PVD Cu seed, then plated Cu (Moffat et al.; Choi and Jeong; DC and RF Magnetron Sputter System page).
• Bath: Copper sulfate, sulfuric acid, about 30 to 50 ppm chloride and organic additives (Moffat et al.; Tang et al.; Novellus).
• Current: About 5 mA/cm${}^2$ in a 300 mm tool, with edge-current control by a second cathode (Choi and Jeong; Novellus).
• After plating: Copper self-anneals at room temperature, and the bump is removed by CMP (Choi and Jeong; CMP Polisher page).

3. Applications

• Damascene interconnects: Bottom-up fill of trenches and vias (Moffat et al.; Metal and Interconnect page).
• Package and PCB microvias: 100 $\mu$m vias filled with levelers (Tang et al.).
• Seedless fill on Ru: 70 nm trenches in about 10 s (Moffat et al.).

Faraday’s Law and Bath

Name	Formula	Related Formulae	Variables/Constants
Faraday’s law	$Q=It,n_e=\frac{Q}{F}$	$C{u}^{2+}+2e^{-}\to Cu,F=96500C/mol$	$\begin{array}{r}Monash:mproportionaltoQ,worked\\ example35.0gCuat5Ainabout21275s\end{array}$ $\begin{array}{r}(computed:35.0/63.5=0.551molneeds\\ 1.10molelectrons)\end{array}$
Plating rate	$v=\frac{jM}{zF\rho }$	$v(5mA/c{\mathrm{m}}^2)\approx 1.8nm/s$	$j:currentdensity$ $M:63.5g/mol,z=2$ $\begin{array}{r}\rho :copperdensity;ChoiandJeong:5mA/c{\mathrm{m}}^2\\ for0.5\mu \mathrm{m};Tangetal.:1.94A/d{\mathrm{m}}^{2}for70\\ \min \end{array}$ $\begin{array}{r}(computed,assuming\rho =8.96g/c{\mathrm{m}}^{3}and100\\ percentefficiency:110\mathrm{nm}/min,0.5\mu \mathrm{m}in\\ 4.5\min ;19.4mA/c{\mathrm{m}}^{2}gives30\mu \mathrm{m}in70\min )\end{array}$
Bath	$CuS{O}_{4}0.24\text{to}0.88mol/L,H_{2}S{O}_{4}10g/L\text{to}1.8mol/L$	$C{l}^{-}\approx 30\text{to}50\mathrm{ppm}$	$\begin{array}{r}Moffatetal.:0.24mol/LCuS{O}_4,1.8mol/L\\ acid,1mmol/LNaCl;Tangetal.:0.88\\ mol/L,0.54mol/L,30ppm;Novellus:40\\ g/L,10g/L,about50mg/L\end{array}$ $(computed:1mmol/Lchlorideis35.5mg/L)$

Additives and Superfill

Name	Formula	Related Formulae	Variables/Constants
Additive roles	$\text{accelerator (SPS)},{\text{suppressor (PEG + Cl}}^{-}),\text{leveler}$	$PEG\text{-}Cl:\text{kinetics}\downarrow \approx 10^2$	$\begin{array}{r}Moffatetal.:SPSatmicromolarlevels\\ needsitssulfonateend,PEGworksonly\\ withchloride;Tangetal.:PEG-C{u}^{+}-C{l}^{-}\\ complex,levelerraisingpolarization,10\\ ppmClgivingnodules\end{array}$ $\begin{array}{r}(myreading:thesuppressorsetsthefield\\ rateandtheacceleratorswitchesitoff\\ locally)\end{array}$
CEAC superfill	$v\propto {\theta }_{acc}$	${\theta }_{acc}\uparrow \text{on concave},\downarrow \text{on convex surfaces}$	$\begin{array}{r}{\theta }_{acc}:localacceleratorcoverage;Moffatet\\ al.:catalyststaysattheinterface,so\\ shrinkingconcavebottomsconcentrateit,\\ initialcoverage0.054ina0.5\mu \mathrm{m}trench\\ simulation\end{array}$ $\begin{array}{r}(myreading:thebottomofafilling\\ trenchshrinksinarea,whichiswhat\\ raisesitscoverage)\end{array}$
Fill timing and bump	$t_{fill}\approx 200\mathrm{s}(0.5\mu mol/LSPS),40\mathrm{s}(500\mu mol/L)$	$\eta =\frac{A}{B}\times 100\%>85\%$	$\begin{array}{r}Moffatetal.:conformalgrowthforabout\\ 60sthensuperfillnear70sinvias,\\ bumpaftercurvatureinverts;Tangetal.:\\ Ain-viathickness,Bsurfacethickness,\\ leveleraboveabout7ppmhurtingfill\end{array}$ $\begin{array}{r}(myreading:thebumpiswhylevelersand\\ CMPfollowplating)\end{array}$

Wafer-Scale Uniformity and Self-Annealing

Name	Formula	Related Formulae	Variables/Constants
Terminal effect	$t_{seed}=5\text{to}150\mathrm{nm},\text{strongest}<1000\text{angstrom}$	${\sigma }_{electrolyte}\approx 0.05(\Omega \mathrm{cm}{)}^{-1}(10g/L{H}_{2}S{O}_4)$	$\begin{array}{r}Novellus:edge-to-centrevoltagedropin\\ theseedgivesaconcaveprofile,mostly\\ intheouter15\mathrm{mm}ofa300\mathrm{mm}wafer;\\ low-acidbathadequateonlyaboveabout\\ 400angstromofseed\end{array}$ $\begin{array}{r}(myreading:thesee{d}^{\prime }ssheetresistance\\ competeswiththeelectrolyteresistance)\end{array}$
Second cathode	$I_2/I_{wafer}=10\%\Rightarrow \text{uniform}$	$5\%:\text{edge thick},15\%:\text{edge thin}$	$\begin{array}{r}Novellus:300angstromseed,200angstrom\\ deposit,cathode2to8cmfromtheedge\\ actinguptoabout20\mathrm{mm}inward,ramped\\ downasthefilmthickens\end{array}$ $\begin{array}{r}(myreading:theterminaleffectfadesas\\ theplatedfilmitselfcarriescurrent)\end{array}$
Self-annealing	$\Delta R_s/R_s\approx -20\%$	$d_{grain}:0.05\text{to}0.2\to \approx 2\mu \mathrm{m},t_{sat}\approx 200\mathrm{h}$	$\begin{array}{r}ChoiandJeong:logarithmictime\\ dependenceafteranincubationperiod,\\ additivessettingtheonset,nohillocks\\ afterthree400{}^{\circ }Cannealswhen\\ self-annealed;Four-PointProbepage\end{array}$ $\begin{array}{r}(computed:agrain-sizeriseof10to40\\ times)\end{array}$

Important Questions

Ques: How does Faraday’s law set the plating thickness?

Thickness follows the charge passed. Monash gives $Q=It$ and $Q=n_{e}F$ with one faraday equal to 96 500 C, and works an example: 35.0 g of copper at 5 A needs 1.10 mol of electrons, since $C{u}^{2+}+2e^{-}\to Cu$, and takes about 21 275 s. Dividing by area and density gives a rate $v=jM/(zF\rho )$. With an assumed copper density of 8.96 $g/c{\mathrm{m}}^3$ and 100 per cent efficiency, Choi and Jeong’s 5 $mA/c{\mathrm{m}}^2$ gives about 110 nm/min, so their 0.5 $\mu \mathrm{m}$ film takes about 4.5 $\min$ (computed). Tang et al. plated at 1.94 $A/d{\mathrm{m}}^2$ for 70 $\min$, which corresponds to about 30 $\mu \mathrm{m}$ on a flat surface (computed). Real current efficiency is below 100 per cent (my reading). Reference: Monash University Student Academic Success, ‘Faraday’s laws’ (electrolysis): Q = I t, Q = n(e-) F with one faraday of 96 500 C, m proportional to Q, m = n M, worked example of 35.0 g Cu at 5 A needing 1.10 mol electrons from Cu2+ + 2e- -> Cu and about 21 275 s (fetch-tool summary); D.-S. Choi and S.-H. Jeong, ‘A study on the self-annealing characteristics of electroplated copper thin film for DRAM integrated process’, Journal of Microelectronics and Packaging Society 25(3), 61-66 (2018): AMAT Raider tool, 5 mA/cm2, 290 angstrom PVD Ta barrier and 550 angstrom Cu seed on 12 inch wafers, 0.5 um Cu, sheet resistance flat then falling with logarithmic time dependence and saturating, about 20 per cent improvement, saturation near 200 h for the evaluation bath and later for the reference bath, grains 0.05 to 0.2 um growing to about 2 um, (100) fraction 32 per cent, additives setting the recrystallization onset, 100 C 30 min stabilization anneal, self-annealed films free of hillocks after three 400 C anneals (fetch-tool summary); M. Tang, S. Zhang, Y. Qiang, S. Chen, L. Luo, J. Gao, L. Feng and Z. Qin, ‘4,6-Dimethyl-2-mercaptopyrimidine as a potential leveler for microvia filling with electroplating copper’, RSC Advances 7, 40342-40353 (2017): 0.88 mol/L CuSO4.5H2O (220 g/L) and 0.54 mol/L H2SO4, chloride 30 ppm (10 ppm giving nodules and explosive growth), SPS 1 ppm, PEG-8000 200 ppm, DMP leveler 1 to 9 ppm with excess above about 7 ppm reducing fill, 1.94 A/dm2 for 70 min at 25 C, 100 um diameter, 80 um deep PCB microvias, filling efficiency eta = A/B x 100 per cent with good fill above 85 per cent, SPS accumulating at the via bottom, PEG-Cu+-Cl- complex suppressing the surface, leveler raising cathodic polarization (fetch-tool summary).

Ques: How do the additives make copper fill trenches from the bottom up?

By the curvature-enhanced accelerator coverage mechanism. Moffat et al. use a prototype bath of copper sulfate, sulfuric acid, chloride, PEG and SPS. PEG works only with chloride as a co-adsorbate and cuts deposition kinetics by nearly two orders of magnitude, while SPS, at micromolar levels, acts as a catalyst. They state that growth velocity is proportional to local accelerator coverage. Because the catalyst stays at the metal-electrolyte interface, it becomes enriched on advancing concave surfaces and diluted on convex ones. As a trench bottom fills and shrinks, its coverage rises, so it grows faster than the sidewalls. In vias, growth was conformal for about 60 s before superfill began near 70 s. Tang et al. describe the same roles in PCB microvias, and the damascene use is on the Metal and Interconnect page. Reference: T. P. Moffat, D. Wheeler and D. Josell (NIST), ‘Superfilling and the curvature enhanced accelerator coverage mechanism’, The Electrochemical Society Interface, Winter 2004, pp. 46-52: prototype bath of about 0.24 mol/L CuSO4, 1.8 mol/L H2SO4, 1.0 mmol/L NaCl, 88 umol/L PEG (3400) and 0 to 500 umol/L SPS, SPS accelerator needing its sulfonate end group, PEG suppressor working only with chloride and cutting kinetics by nearly two orders of magnitude, growth velocity proportional to local accelerator coverage, catalyst enriching on concave and diluting on convex surfaces, bottom-up superfill of submicrometre trenches with simulated 0.5 um trench and initial SPS coverage 0.054, fill times about 200 s at 0.5 umol/L and about 40 s at 500 umol/L derivatization, conformal growth for about 60 s before superfill at about 70 s in vias, bump formation after curvature inverts with a large bump by 100 s, growth at -0.25 V, Ta barrier with PVD Cu seed, seedless superfill on Ru filling 70 nm trenches in about 10 s, leveler as a third component in commercial packages (fetch-tool summary); M. Tang, S. Zhang, Y. Qiang, S. Chen, L. Luo, J. Gao, L. Feng and Z. Qin, ‘4,6-Dimethyl-2-mercaptopyrimidine as a potential leveler for microvia filling with electroplating copper’, RSC Advances 7, 40342-40353 (2017): 0.88 mol/L CuSO4.5H2O (220 g/L) and 0.54 mol/L H2SO4, chloride 30 ppm (10 ppm giving nodules and explosive growth), SPS 1 ppm, PEG-8000 200 ppm, DMP leveler 1 to 9 ppm with excess above about 7 ppm reducing fill, 1.94 A/dm2 for 70 min at 25 C, 100 um diameter, 80 um deep PCB microvias, filling efficiency eta = A/B x 100 per cent with good fill above 85 per cent, SPS accumulating at the via bottom, PEG-Cu+-Cl- complex suppressing the surface, leveler raising cathodic polarization (fetch-tool summary); Metal and Interconnect page of this vault.

Ques: What is the bump, and what do levelers do?

The bump is overgrowth above filled features. Moffat et al. explain that once the bottom reaches the top, curvature inverts, the enriched accelerator persists and a bump forms, visible by 100 s in their samples. Fill time depends on accelerator dose, about 200 s at 0.5 $\mu mol/L$ SPS derivatization against about 40 s at 500 $\mu mol/L$. Commercial packages add a third component, the leveler. Tang et al. show that their DMP leveler adsorbs on copper and raises cathodic polarization. Fill efficiency, $\eta =A/B\times 100$ per cent, rose to above 85 per cent, but excess leveler above about 7 ppm reduced it. Chloride at 10 ppm instead of 30 ppm gave nodules and explosive growth. The remaining overburden is removed by CMP (CMP Polisher page; my reading). Reference: T. P. Moffat, D. Wheeler and D. Josell (NIST), ‘Superfilling and the curvature enhanced accelerator coverage mechanism’, The Electrochemical Society Interface, Winter 2004, pp. 46-52: prototype bath of about 0.24 mol/L CuSO4, 1.8 mol/L H2SO4, 1.0 mmol/L NaCl, 88 umol/L PEG (3400) and 0 to 500 umol/L SPS, SPS accelerator needing its sulfonate end group, PEG suppressor working only with chloride and cutting kinetics by nearly two orders of magnitude, growth velocity proportional to local accelerator coverage, catalyst enriching on concave and diluting on convex surfaces, bottom-up superfill of submicrometre trenches with simulated 0.5 um trench and initial SPS coverage 0.054, fill times about 200 s at 0.5 umol/L and about 40 s at 500 umol/L derivatization, conformal growth for about 60 s before superfill at about 70 s in vias, bump formation after curvature inverts with a large bump by 100 s, growth at -0.25 V, Ta barrier with PVD Cu seed, seedless superfill on Ru filling 70 nm trenches in about 10 s, leveler as a third component in commercial packages (fetch-tool summary); M. Tang, S. Zhang, Y. Qiang, S. Chen, L. Luo, J. Gao, L. Feng and Z. Qin, ‘4,6-Dimethyl-2-mercaptopyrimidine as a potential leveler for microvia filling with electroplating copper’, RSC Advances 7, 40342-40353 (2017): 0.88 mol/L CuSO4.5H2O (220 g/L) and 0.54 mol/L H2SO4, chloride 30 ppm (10 ppm giving nodules and explosive growth), SPS 1 ppm, PEG-8000 200 ppm, DMP leveler 1 to 9 ppm with excess above about 7 ppm reducing fill, 1.94 A/dm2 for 70 min at 25 C, 100 um diameter, 80 um deep PCB microvias, filling efficiency eta = A/B x 100 per cent with good fill above 85 per cent, SPS accumulating at the via bottom, PEG-Cu+-Cl- complex suppressing the surface, leveler raising cathodic polarization (fetch-tool summary); CMP Polisher page of this vault.

Ques: Why does the wafer edge plate thicker, and how is it corrected?

Because of the terminal effect in the thin seed. Novellus explains that current enters at contacts on the wafer edge, and the voltage drop across the resistive PVD seed, typically 5 to 150 $\mathrm{nm}$, makes the edge plate faster, giving a concave profile thicker at the edge. The effect is strongest below about 1000 angstrom of seed and is mostly within the outer 15 $\mathrm{mm}$ of a 300 $\mathrm{mm}$ wafer. Their fix is a second cathode 2 to 8 cm from the edge. Diverting 10 per cent of the wafer current gave a uniform 200 angstrom layer on a 300 angstrom seed, while 5 per cent left the edge thick and 15 per cent made it slightly thin. The seed itself comes from PVD (DC and RF Magnetron Sputter System page). Reference: J. Reid, S. Varadarajan, B. Buckalew, P. Breiling and G. Ibarreta (Novellus Systems), ‘Method and apparatus for electroplating including remotely positioned second cathode’, US Patent 7,854,828 (2010): PVD Cu seed about 5 to 150 nm, terminal effect strongest below about 1000 angstrom, voltage drop from edge contacts to centre giving a concave profile thicker at the edge, concentrated in the outer 15 mm of a 300 mm wafer, 10 g/L sulfuric acid with conductivity about 0.05 (ohm cm)-1 redistributing current adequately only for seeds above about 400 angstrom, example bath 40 g/L copper sulfate, 10 g/L sulfuric acid and about 50 mg/L chloride, wafer currents 2.25 to 9 A rising to 9 to 50 A, a second cathode 2 to 8 cm from the edge acting up to about 20 mm inward, 10 per cent of wafer current giving a uniform 200 angstrom layer on a 300 angstrom seed while 5 per cent left the edge thick and 15 per cent slightly thin (fetch-tool summary); DC and RF Magnetron Sputter System page of this vault.

Ques: What is self-annealing in plated copper?

Room-temperature recrystallization after plating. Choi and Jeong plated 0.5 $\mu \mathrm{m}$ of copper at 5 $mA/c{\mathrm{m}}^2$ on a 550 angstrom seed over 290 angstrom of Ta in an AMAT Raider tool. Sheet resistance stayed flat at first, then fell with a logarithmic time dependence and saturated after about 200 $\mathrm{h}$ for one bath, with an improvement of about 20 per cent. Grains grew from 0.05 to 0.2 $\mu \mathrm{m}$ to about 2 $\mu \mathrm{m}$, 10 to 40 times (computed), and the (100) fraction reached 32 per cent. Organic additives set when recrystallization starts, and the two baths differed in saturation time. Self-annealed films showed no hillocks after three 400 ${}^{\circ }\mathrm{C}$ anneals. Sheet resistance is tracked with the Four-Point Probe page method (my reading). Reference: D.-S. Choi and S.-H. Jeong, ‘A study on the self-annealing characteristics of electroplated copper thin film for DRAM integrated process’, Journal of Microelectronics and Packaging Society 25(3), 61-66 (2018): AMAT Raider tool, 5 mA/cm2, 290 angstrom PVD Ta barrier and 550 angstrom Cu seed on 12 inch wafers, 0.5 um Cu, sheet resistance flat then falling with logarithmic time dependence and saturating, about 20 per cent improvement, saturation near 200 h for the evaluation bath and later for the reference bath, grains 0.05 to 0.2 um growing to about 2 um, (100) fraction 32 per cent, additives setting the recrystallization onset, 100 C 30 min stabilization anneal, self-annealed films free of hillocks after three 400 C anneals (fetch-tool summary); Four-Point Probe page of this vault.

Ques: What bath composition is typical, and which chloride level is more likely right?

About 30 to 50 ppm chloride; the bath varies more in acid. Moffat et al. use 1.0 mmol/L NaCl, which is 35.5 $mg/L$ of chloride (computed), with 0.24 $mol/L$ CuSO${}_4$ and 1.8 $mol/L$ H${}_2$SO${}_4$. Tang et al. use 30 ppm with 0.88 $mol/L$ CuSO${}_4$ and 0.54 $mol/L$ acid, and report nodules at 10 ppm. Novellus gives about 50 $mg/L$ with 40 $g/L$ copper sulfate and only 10 $g/L$ acid. The chloride values agree within a factor of about 1.7, so 30 to 50 ppm is the likely working range. The acid levels differ by more than ten times, and Novellus links low acid to electrolyte conductivity and terminal-effect control. These are therefore deliberate design choices rather than a disagreement (my reading). Reference: T. P. Moffat, D. Wheeler and D. Josell (NIST), ‘Superfilling and the curvature enhanced accelerator coverage mechanism’, The Electrochemical Society Interface, Winter 2004, pp. 46-52: prototype bath of about 0.24 mol/L CuSO4, 1.8 mol/L H2SO4, 1.0 mmol/L NaCl, 88 umol/L PEG (3400) and 0 to 500 umol/L SPS, SPS accelerator needing its sulfonate end group, PEG suppressor working only with chloride and cutting kinetics by nearly two orders of magnitude, growth velocity proportional to local accelerator coverage, catalyst enriching on concave and diluting on convex surfaces, bottom-up superfill of submicrometre trenches with simulated 0.5 um trench and initial SPS coverage 0.054, fill times about 200 s at 0.5 umol/L and about 40 s at 500 umol/L derivatization, conformal growth for about 60 s before superfill at about 70 s in vias, bump formation after curvature inverts with a large bump by 100 s, growth at -0.25 V, Ta barrier with PVD Cu seed, seedless superfill on Ru filling 70 nm trenches in about 10 s, leveler as a third component in commercial packages (fetch-tool summary); M. Tang, S. Zhang, Y. Qiang, S. Chen, L. Luo, J. Gao, L. Feng and Z. Qin, ‘4,6-Dimethyl-2-mercaptopyrimidine as a potential leveler for microvia filling with electroplating copper’, RSC Advances 7, 40342-40353 (2017): 0.88 mol/L CuSO4.5H2O (220 g/L) and 0.54 mol/L H2SO4, chloride 30 ppm (10 ppm giving nodules and explosive growth), SPS 1 ppm, PEG-8000 200 ppm, DMP leveler 1 to 9 ppm with excess above about 7 ppm reducing fill, 1.94 A/dm2 for 70 min at 25 C, 100 um diameter, 80 um deep PCB microvias, filling efficiency eta = A/B x 100 per cent with good fill above 85 per cent, SPS accumulating at the via bottom, PEG-Cu+-Cl- complex suppressing the surface, leveler raising cathodic polarization (fetch-tool summary); J. Reid, S. Varadarajan, B. Buckalew, P. Breiling and G. Ibarreta (Novellus Systems), ‘Method and apparatus for electroplating including remotely positioned second cathode’, US Patent 7,854,828 (2010): PVD Cu seed about 5 to 150 nm, terminal effect strongest below about 1000 angstrom, voltage drop from edge contacts to centre giving a concave profile thicker at the edge, concentrated in the outer 15 mm of a 300 mm wafer, 10 g/L sulfuric acid with conductivity about 0.05 (ohm cm)-1 redistributing current adequately only for seeds above about 400 angstrom, example bath 40 g/L copper sulfate, 10 g/L sulfuric acid and about 50 mg/L chloride, wafer currents 2.25 to 9 A rising to 9 to 50 A, a second cathode 2 to 8 cm from the edge acting up to about 20 mm inward, 10 per cent of wafer current giving a uniform 200 angstrom layer on a 300 angstrom seed while 5 per cent left the edge thick and 15 per cent slightly thin (fetch-tool summary).

References

1. Monash University, “Faraday’s laws,” Student Academic Success: chemistry, electrolysis. Available: https://www.monash.edu/student-academic-success/chemistry/electrolysis/faradays-laws
2. T. P. Moffat, D. Wheeler and D. Josell, “Superfilling and the curvature enhanced accelerator coverage mechanism,” The Electrochemical Society Interface, Winter 2004, pp. 46-52. Available: https://www.electrochem.org/dl/interface/wtr/wtr04/IF12-04-Pg46.pdf
3. M. Tang, S. Zhang, Y. Qiang, S. Chen, L. Luo, J. Gao, L. Feng and Z. Qin, “4,6-Dimethyl-2-mercaptopyrimidine as a potential leveler for microvia filling with electroplating copper,” RSC Advances, vol. 7, pp. 40342-40353, 2017, doi:10.1039/c7ra06857c. Available: https://pubs.rsc.org/en/content/articlepdf/2017/ra/c7ra06857c
4. J. Reid, S. Varadarajan, B. Buckalew, P. Breiling and G. Ibarreta, “Method and apparatus for electroplating including remotely positioned second cathode,” US Patent 7,854,828, Novellus Systems, 2010. Available: https://patents.google.com/patent/US7854828
5. D.-S. Choi and S.-H. Jeong, “A study on the self-annealing characteristics of electroplated copper thin film for DRAM integrated process,” Journal of Microelectronics and Packaging Society, vol. 25, no. 3, pp. 61-66, 2018. Available: https://koreascience.kr/article/JAKO201835372299566.pdf
6. Metal and Interconnect page of this vault.
7. CMP Polisher page of this vault.
8. DC and RF Magnetron Sputter System page of this vault.
9. Four-Point Probe page of this vault.

Related pages in this vault: Metal and Interconnect, CMP Polisher, DC and RF Magnetron Sputter System, Four-Point Probe, Electron Backscatter Diffraction (EBSD).