PVD (Physical Vapor Deposition ) Technology

1. PVD (Physical Vapor Deposition )Technology tsmc FAB 14 吳佳俊

2. Outline • What is Plasma • Convention PVD Process (DC plasma) • DC Plasma PVD bottle neck • What is RF ( Radio frequency ) • PVD Chamber H/W Evolution • Metal line process overview • tsmc introduction • EE responsibility • Q & A

3. What is Plasma ? • 電  Electrical Particles • 漿  Collective motion • It contains highly reactive gas species • It emits light  glow (O2->whitish-blue, N2->pink) • It is driven by electric energy  electric field

4. Plasma Components • Created by current through a gas • Gas is partially ionized • Quasi-neutral plasma • Nearly equal numbers of positive ( ) and negative ( )

5. Basic Plasma Concept • Ionization • Initially, very few electrons are present in neutral gas • The electrons are accelerated by energy input • Newly produced electrons accelerate and ionize more neutrals • Ionized avalanche happened • Equi-potential cloud plasma is formed

6. Basic Plasma Concept • Excitation-Relaxation • Light is emitted

7. Basic Plasma Concept • Dissociation • When an electron collides with a molecule with enough energy • Break its bonding energy into apart • Much less energy than ionization • Much higher dissociation rate than ionization

9. DC Plasma • Initiation of The Plasma • Plasma is formed when an avalanche of ionization occurs • This results in a sea of positive and negative charged particles • The gas into plasmas transition involves going from insulating medium to conductive medium

10. PVD Dry-ETCH HDP-CVD Basic Plasma Concept • Steady plasma source • Energetic electron (Plasma type) • Appropriate collision (Recipe) • Plasma sustain (Geometry design)

11. PVD(Physical Vapor Deposition) Process (DC plasma Deposition)

12. Sputtering • Momentum transfer will dislodge surface atom off • About 70% energy converts to heat • About 25% energy generates secondary electrons • Secondary electrons ionize Ar

13. DC Magnets Sputtering • Film Uniformity • High target utilization • Full face erosion • Plasma ignition & sustaining • Step coverage

14. DC Magnets Sputtering

15. Convention PVD (DC Plasma) • Target (Metal source) • Plasma • Gas • Pump • Pedestal

16. -V Pedestal Convention PVD Process • Ion generated & toward a target • Atoms sputter from target • Sputtered atoms traverse to substrate • Condense • Nucleated • Form a film

17. Film Growth Overview • Formation of isolated nuclei • Island formation • Formation continuous film grain boundaries • Grain growth

18. DC Sputtering Deposition Schematic

19. W h SiO2 DC Plasma PVD Bottle Neck • Aspect Ratio (h/w) • Step Coverage

20. Collimator PVD • Lower deposition rate • Potential Particle issue • Shorter PM cycle

21. Long throw PVD • Lower deposition rate • Worse film uniformity • Shorter PM cycle L

22. PVD(Physical Vapor Deposition) Process (RF plasma Deposition)

23. RF microwave audio 20 kHz 300 MHz What is RF ? • AC frequencies

24. 13.56MHz Radio Frequency Radio frequency

25. Why need to use AC Plasma ? • Step Coverage Ration

26. DC Biasing of RF • RF power couples through the wafer like a capacitor • On-average, the wafer is biased negative (attracts ions)

27. AC Capacitive Discharge

28. Bias Effect

30. RF Power • Forward Power • Power from RF generator • Reflected Power • Power return to RF generator • Load Power • Power consumed by load Direction Coupler

31. Impedance (Z) • Made up of two parts • Resistance • Reactance (Capacitive & Inductive) • Most RF generator are designed to operate into a 50  load • Plasma impedance ZL dependent on Power • Gas pressure and chemistry • Power level and frequency • Chamber materials and geometry’s

32. Maximum Power Theorem • Maximum power when ZS = ZL • RF generator ZS = (50  j0) • ZS  ZL Reflected power increased • RF tuner is required to transform ZS = ZL

33. RF Matching Network • Manual match • Auto match • Air capacitor (for low power / fast response) • Vacuum capacitor (for high power / low response) • Fixed match • The most fast response / acceptable reflected power at certain VSWR • Switching match (fast response)

34. IMP (Ion Metal Plasma) Chamber • DC RF source generate Medium density Plasma • Add coil DC • Coil sputtering, blocking capacitor • Increase pedestal bias potential

35. Incident Angle Distribution

36. PVD Technology Trend

37. SIP Technology • Self ionized Plasma • Sputter discharge in which the dominate ionized species is from the target • Higher ionization rate and enough self-sputter yield to sustain plasma without Ar gas • Plasma Characteristics • High power • Low pressure

38. SIP Process • Large wafer to target spacing • Leads to “long-throw” directional trajectories for neutral • Unbalance Magnet • Control ion trajectories • Cooled, biased substrate

39. SIP EnCoRe Cu

40. SIP EnCoRe Cu

41. PVD Technology Evolution

42. Metal Line Process Overview

44. AMAT EnCoRe Barrier/Cu Seed

45. Ch D (PC II) FI PVD 4 (Cu) Ta Ch F (Degas) PVD 3 (TaN) TaN SWLL B LP 2 SWLL A PVD 2 (TaN) Ch E (Degas) PVD 1 (Cu) Ch C (PC II) LP 1 AMAT EnCoRe Barrier/Cu Seed

46. ECP (Electric Chemical Plating)

47. NVLS Sabre ECP

48. NVLS Sabre ECP

49. CMP (Chemical Mechanical Polish)

50. AMAT Reflexion CMP