1. EE141 © Digital Integrated Circuits 2nd Manufacturing 1 Digital Integrated Circuits A Design Perspective Manufacturing Process Jan M. Rabaey Anantha Chandrakasan Borivoje Nikolic Revised from Digital Integrated Circuits, © Jan M. Rabaey el, 2003

2. EE141 © Digital Integrated Circuits 2nd Manufacturing 2 Goal of Chapter 2  Understand the basic CMOS manufacturing steps  Understand layout of transistors  Understand layout rules

3. EE141 © Digital Integrated Circuits 2nd Manufacturing 3 CMOS n-well Process

4. EE141 © Digital Integrated Circuits 2nd Manufacturing 4 Modern dual-well CMOS Process Dual-Well Trench-Isolated CMOS Process

5. EE141 © Digital Integrated Circuits 2nd Manufacturing 5 Circuit Under Design

6. EE141 © Digital Integrated Circuits 2nd Manufacturing 6 Its Layout View

7. EE141 © Digital Integrated Circuits 2nd Manufacturing 7 oxidation optical mask process step photoresist coatingphotoresist removal (ashing) spin, rinse, dry acid etch photoresist stepper exposure development Typical operations in a single photolithographic cycle (from [Fullman]). Photo-Lithographic Process

8. EE141 © Digital Integrated Circuits 2nd Manufacturing 8 Patterning of SiO2: create isolation Si-substrate (a) Silicon base material (b) After oxidation and deposition of negative photoresist (c) Stepper exposure Photoresist SiO 2 UV-light Patterned optical mask Exposed resist SiO 2 Si-substrate SiO 2 2 (d) After development and etching of resist, chemical or plasma etch of SiO 2 (e) After etching (f) Final result after removal of resist Hardened resist Chemical or plasma etch

9. EE141 © Digital Integrated Circuits 2nd Manufacturing 9 CMOS Process at a Glance Define active areas Etch and fill trenches Implant well regions Deposit and pattern polysilicon layer Implant source and drain regions and substrate contacts Create contact and via windows Deposit and pattern metal layers

10. EE141 © Digital Integrated Circuits 2nd Manufacturing 10 CMOS Process Walk-Through p + p-epi (a) Base material: p+ substrate with p-epi layer p+ (c) After plasma etch of insulating trenches using the inverse of the active area mask p + p-epi SiO 2 3 SiN 4 (b) After deposition of gate-oxide and sacrificial nitride (acts as a buffer layer)

11. EE141 © Digital Integrated Circuits 2nd Manufacturing 11 CMOS Process Walk-Through SiO 2 (d) After trench filling, CMP planarization, and removal of sacrificial nitride (e) After n-well and V Tp adjust implants n (f) After p-well and V Tn adjust implants p

12. EE141 © Digital Integrated Circuits 2nd Manufacturing 12 CMOS Process Walk-Through (g) After polysilicon deposition and etch poly(silicon) Nwell Pwell

13. EE141 © Digital Integrated Circuits 2nd Manufacturing 13 CMOS Process Walk-Through

14. EE141 © Digital Integrated Circuits 2nd Manufacturing 14 Advanced Metallization

15. EE141 © Digital Integrated Circuits 2nd Manufacturing 15 The Manufacturing Process For a great tour through the IC manufacturing process and its different steps, check http://www.fullman.com/semiconductors/semiconductors.html

16. EE141 © Digital Integrated Circuits 2nd Manufacturing 16 Design Rules

17. EE141 © Digital Integrated Circuits 2nd Manufacturing 17 3D Perspective Polysilicon Aluminum

18. EE141 © Digital Integrated Circuits 2nd Manufacturing 18 Design Rules  Interface between designer and process engineer  Guidelines for constructing process masks  Unit dimension: Minimum length  scalable design rules: lambda parameter (SCMOS SUBMICRON Design Rules) Technology=2 lambda  absolute dimensions (micron rules)

19. EE141 © Digital Integrated Circuits 2nd Manufacturing 19 Layers in 0.25  m CMOS process

20. EE141 © Digital Integrated Circuits 2nd Manufacturing 20 CMOS Process Layers (an example) Layer Polysilicon Metal1 Metal2 Contact To Poly Contact To Diffusion Via Well (p,n) Active Area (n+,p+) ColorRepresentation Yellow Green Red Blue Magenta Black Select (p+,n+) Green

21. EE141 © Digital Integrated Circuits 2nd Manufacturing 21 Intra-Layer Design Rules Metal2 4 3

22. EE141 © Digital Integrated Circuits 2nd Manufacturing 22 Transistor Layout

23. EE141 © Digital Integrated Circuits 2nd Manufacturing 23 Vias and Contacts

24. EE141 © Digital Integrated Circuits 2nd Manufacturing 24 CMOS Inverter Layout

25. EE141 © Digital Integrated Circuits 2nd Manufacturing 25 Layout Editor

26. EE141 © Digital Integrated Circuits 2nd Manufacturing 26 Design Rule Check poly_not_fet to all_diff minimum spacing = 0.14 um.

27. EE141 © Digital Integrated Circuits 2nd Manufacturing 27 Sticks Diagram 1 3 In Out V DD GND Stick diagram of inverter Dimensionless layout entities Only topology is important Final layout generated by “compaction” program

28. EE141 © Digital Integrated Circuits 2nd Manufacturing 28