IBM/Motorola MPC750 RISC Microprocessor
Transcription
IBM/Motorola MPC750 RISC Microprocessor
Construction Analysis IBM/Motorola MPC750 RISC Microprocessor a e lS miconductor In d us try Since 1964 n Servi g the G lo b Report Number: SCA 9711-563 ® 17350 N. Hartford Drive Scottsdale, AZ 85255 Phone: 602-515-9780 Fax: 602-515-9781 e-mail: ice@ice-corp.com Internet: http://www.ice-corp.com INDEX TO TEXT TITLE PAGE INTRODUCTION MAJOR FINDINGS 1 1 TECHNOLOGY DESCRIPTION Assembly Die Process 2 2-3 ANALYSIS RESULTS I Assembly 4 ANALYSIS RESULTS II Die Process and Design 5-8 ANALYSIS PROCEDURE 9 TABLES Overall Evaluation Package Markings Die Material Analysis Horizontal Dimensions Vertical Dimensions 10 11 11 12 13 -i- INTRODUCTION This report describes a construction analysis of the IBM/Motorola MPC750 RISC Microprocessor. Two engineering samples (275 MHz) were used for the analysis. The devices were received in 361-pin (360 actual) ceramic BGA packages. Although no date code was present on the devices, they are believed to have been fabbed in the second half of 1997. MAJOR FINDINGS Questionable Items:1 None. Special Features: • Six metal, P-epi, CMOS process. • Very aggressive feature size: 0.17 micron gates (0.15 micron effective?). • Metal 1 (tungsten) was defined by a damascene process. Stacked vias were employed. • Chemical-mechanical-planarization (CMP). • Oxide-filled shallow-trench isolation. • Titanium silicided diffusion structures. 1These items present possible quality or reliability concerns. They should be discussed with the manufacturer to determine their possible impact on the intended application. -1- TECHNOLOGY DESCRIPTION Assembly: • The devices were packaged in 361-pin (360 actual) ceramic ball grid arrays (BGAs). The die was mounted surface down on the ceramic substrate (C4 flip-chip assembly). • A blue colored underfill was present between the die surface and the ceramic substrate. • External package solder balls were employed for package to board connections. • Solder balls were employed for all connections to die metallization (C4 flip-chip process). Copper-tin bond pads were employed with a chromium barrier. • Sawn dicing (full depth). Die Process: • Fabrication process: Oxide-filled shallow-trench isolation, CMOS process employing twin-wells in an apparent P-epi on a P substrate. • Die coat: A thin patterned polyimide die coat was present over the entire die. • Final passivation: A layer of nitride over a layer of glass. • Metallization: Six levels of metal defined by dry-etch techniques. Metal 1 (tungsten) was defined by a damascene process. Metals 2 - 6 consisted of aluminum with titanium-nitride caps. Metal 6 employed a titanium barrier which was also probably used under metals 2 - 5, but was too thin to delineate clearly. Tungsten plugs were employed for vias under metals 2 - 6. All tungsten plugs and tungsten metal 1 were lined with titanium-nitride. Stacked vias were employed at all levels. -2- TECHNOLOGY DESCRIPTION (continued) • Intermetal dielectrics: Intermetal dielectrics 2 - 5 used the same dielectric structure. Two layers of glass were deposited. The first layer was subjected to an etchback and the second layer was planarized by chemical-mechanical-planarization (CMP). Intermetal dielectric 1 (between M1 and M2) consisted of a single thick layer of glass which had also been subjected to CMP (after M1 deposition). • Pre-metal glass: A thick layer of glass over a thin nitride. This dielectric was also planarized by CMP (after metal 1 deposition). • Polysilicon: A single layer of dry-etched polycide (poly and titanium-silicide). This layer was used to form all gates on the die. Oxide sidewall spacers were used to provide the LDD spacing. • Diffusions: Implanted N+ and P+ diffusions formed the sources/drains of transistors. Titanium was sintered into the diffusions (salicide process). • Isolation: Field oxide isolation consisted of oxide-filled shallow-trench isolation. It was very planar with the diffused silicon surfaces. • Wells: Twin-wells in a P-epi on a P substrate. • Memory cells: On-chip Level 1 data and instruction Cache memory cell arrays (32KByte each) were employed. On-chip Level 2 Cache was also employed. Both Cache memory cells used a 6T CMOS SRAM cell design although the layout differed. It is not apparent which cells were Level 1 or 2 Cache memory, so they are referred to as Array A and Array B (see Figures 40 - 43). On Array A metal 3 distributed GND and bit lines (via metals 1 3). Metal 2 distributed Vcc and formed “piggyback” word lines throughout the cells and was used as cell interconnect. Metal 1 also provided cell interconnect. Poly formed the select and storage gates. On Array B metal 3 formed the bit lines, metal 2 distributed GND and Vcc and formed “piggyback” word line. Metal 1 formed cell interconnect and poly formed the gates. Cell size on Array A was 4 x 6.7 microns and on Array B was 3.3 x 4.8 microns. • Metal 5 redundancy fuses were present. Metal 5 aluminum fuse links were connected to the tungsten below. No blown fuse links were present. Passivation cutouts were present over the fuse blocks. -3- ANALYSIS RESULTS I Assembly : Figures 1 and 5 Questionable Items:1 None. Special Features: None. General items: • The devices were packaged in 361-pin ceramic BGA packages. The die was mounted surface down on the ceramic (flip-chip assembly). • Overall package quality: Good. No defects were found on the external portions of the packages. External solder balls were well formed and placed. • Die connections: Solder balls were used for connections to the die (C4 process). A separate metal layer (copper-tin over a chromium barrier) formed the bond pads. Pads were connected to the metal 6 through cutouts in the passivation and die coat. Ball placement was good. Pad size was 4.5 mils (round) and ball pad pitch was 9.9 mils. A blue colored underfill was present between the die and the ceramic substrate. No voids were noted in this material. • Die dicing: Die separation was by full depth sawing and showed normal quality workmanship. No large chips or cracks were present at the die edges. 1These items present possible quality or reliability concerns. They should be discussed with the manufacturer to determine their possible impact on the intended application. -4- ANALYSIS RESULTS II Die Process and Design: Figures 2 - 43 Questionable Items:1 • Misalignment of metal 3 to the underlying tungsten plugs (Figures 23 - 24). Special Features: • Six metal, P-epi, CMOS process. • Aggressive gate sizes (0.17 micron). • Metal 1 (tungsten) was defined by a damascene process. Stacked vias were employed. • Chemical-mechanical-planarization (CMP). • Oxide-filled shallow-trench isolation. • Titanium silicided diffusion structures. General Items: • Fabrication process: Oxide-filled shallow-trench isolation, CMOS process employing twin-wells in an apparent P-epi on a P substrate. No problems were found in the process. • Design implementation: Die layout was clean and efficient. Alignment was good at all levels (except metal 3 to underlying plugs). • Surface defects: No toolmarks, masking defects, or contamination areas were found. • Die coat: A patterned polyimide die coat was present over the entire die surface. 1These items present possible quality or reliability concerns. They should be discussed with the manufacturer to determine their possible impact on the intended application. -5- ANALYSIS RESULTS II (continued) • Final passivation: A layer of nitride over a layer of glass. Coverage was good. Edge seal was also good as the passivation extended to the scribe lane to seal the metallization. • Metallization: Six levels of metal interconnect. Metals 2 - 6 consisted of aluminum with titanium-nitride caps. Metal 6 employed a titanium barrier which was also probably used under metals 2 - 5, but was too thin to delineate clearly. Tungsten plugs were employed with metals 2 - 6. All plugs were lined with titanium-nitride underneath. Metal 1 was used as a local interconnect and consisted of tungsten defined by a damascene process. The metal 1 tungsten was also lined with titaniumnitride. • Metal patterning: All aluminum metal levels were defined by a dry etch of good quality. Metal 6 profiles were somewhat unusual (see Figure 10). Some metal lines were widened slightly at via connections. • Metal defects: None. No voiding, notching or cracking of the metal layers was found. No silicon nodules were found following removal of the metal layers. • Metal step coverage: No metal thinning was present at the connections to the tungsten via plugs or metal 1. The absence of thinning is due to the good control of plug height and the planarization technique employed. • Vias and contacts: All via and contact cuts were defined by a dry etch of good quality. Again, alignment of the metals and plugs was good (except metal 3). Metal 3 was misaligned to the metal 3 plugs below (see Figures 23 and 24). This misalignment decreased contact area by approximately 50 percent and decreased adjacent metal-to-tungsten plug spacing. This does not appear to be a serious concern. Vias and contacts were placed directly over one another (stacked vias). No problems were noted. -6- ANALYSIS RESULTS II (continued) • Intermetal dielectrics: Intermetal dielectrics 2 - 5 consisted of the same type of oxide structure. Two layers of glass were deposited, the first layer was subjected to a sputter etchback and the second layer of glass was subjected to CMP which left the surface very planar. Intermetal dielectric 1 consisted of a single thick layer of glass which had also been subjected to CMP. No problems were found with any of these layers. • Pre-metal glass: A thick layer of silicon-dioxide over a thin nitride. This layer was also planarized by chemical-mechanical-planarization. No problems were found. • Polysilicon: A single level of polycide (poly and titanium-silicide) was used. It formed all gates and word lines in the array. Definition was by dry etch of good quality. Oxide sidewall spacers were used throughout and left in place. No problems were found. • Isolation: The device used oxide-filled shallow-trench isolation which was quite planar with the silicon surface. No problems were present. • Diffusions: Implanted N+ and P+ diffusions were used for sources and drains. Titanium was sintered into the diffusions (salicide process) to reduce series resistance. An LDD process was used employing sidewall spacers. • Wells: Twin-wells were used in what we believe to be a P-epi on a P substrate. Definition was normal, although we could not delineate the P-well. • Buried contacts: Direct poly to diffusion contacts were not used. • Memory cells: On-chip Level 1 data and instruction Cache memory cell arrays (32KByte each) were employed. On-chip Level 2 Cache was also employed. Both Cache memory cells used 6T CMOS SRAM cell design although the layout differed. It is not apparent which cells were Level 1 or 2 Cache memory, so they are referred to as Array A and Array B (see Figures 40 - 43). On Array A metal 3 distributed GND and bit lines (via metals 1 - 3). Metal 2 distributed Vcc and formed “piggyback” word lines throughout the cells and was used as cell interconnect. Metal 1 also provided cell interconnect. Poly formed the select and storage gates. On Array B metal 3 formed the bit lines, metal 2 distributed GND and Vcc and formed “piggyback” word lines. Metal 1 formed cell interconnect and poly formed the gates. Cell size on Array A was 4 x 6.7 microns and on Array B was 3.3 x 4.8 microns. -7- ANALYSIS RESULTS II (continued) • Metal 5 redundancy fuses were present. Metal 5 aluminum formed the fuse links and were connected to tungsten plugs below. No blown fuse links were present. Passivation cutouts were present over the fuse blocks. No problems were seen. -8- PROCEDURE The devices were subjected to the following analysis procedures: External inspection X-ray Die optical inspection Delayer to metal 6 and inspect Aluminum removal (metal 6) and inspect plugs Delayer to metal 5 and inspect Aluminum removal (metal 5) and inspect tungsten plugs Delayer to metal 4 and inspect Aluminum removal (metal 4) and inspect tungsten plugs Delayer to metal 3 and inspect Aluminum removal (metal 3) and inspect tungsten plugs Delayer to metal 2 and inspect Aluminum removal (metal 2) and inspect tungsten plugs Delayer to metal 1 and inspect Tungsten removal (metal 1) Delayer to polycide/substrate and inspect Die sectioning (90° for SEM) Measure horizontal dimensions Measure vertical dimensions Die material analysis -9- OVERALL QUALITY EVALUATION: Overall Rating: Normal to Good. DETAIL OF EVALUATION Package integrity Package markings Die placement Solder ball placement Solder ball interconnect quality Dicing quality Die attach quality Die attach method Dicing method G G G G G G G C4 solder ball interconnect technique Sawn Die surface integrity: Toolmarks (absence) Particles (absence) Contamination (absence) Process defects (absence) General workmanship Passivation integrity Metal definition Metal integrity G G G G G G G G Metal registration N* Contact coverage N* Via/contact registration Etch control (depth) N N *Misalignment of metal 3 to underlying plugs. G = Good, P = Poor, N = Normal, NP = Normal/Poor - 10 - PACKAGE MARKINGS TOP (lid) IBM R25000PAP Arthur 88H5811 A1M010 275 (handmarked) DIE MATERIAL ANALYSIS Final passivation: Single layer of nitride over a glass layer. Metallization 2 - 6: Aluminum with titanium-nitride caps and apparent thin titanium adhesion layers. Intermetal dielectrics 2 - 5: A layer of glass followed by another layer of glass which was planarized by CMP. Intermetal dielectric 1: Thick layer of glass (CMP planarization). Metallization 1: Tungsten (damascene process) with titanium-nitride liner. Vias (M2 - M5): Tungsten (lined with titanium-nitride). Pre-metal glass: Thick layer of silicon-dioxide over a thin nitride. Polycide: Titanium-silicide on polysilicon. Salicide on diffusions: Titanium-silicide. - 11 - HORIZONTAL DIMENSIONS Die size: 7.8 x 9 mm (308 x 356 mils) Die area: Min pad size: Min pad space: Min metal 6 width: Min metal 6 space: Min metal 6 pitch: Min metal 5 width: Min metal 5 space: Min metal 5 pitch: Min metal 4 width: Min metal 4 space: Min metal 4 pitch: Min metal 3 width: Min metal 3 space: Min metal 3 pitch: Min metal 2 width: Min metal 2 space: Min metal 2 pitch: Min metal 1 width: Min metal 1 space: Min via (M6-to-M5): Min via (M5-to-M4): Min via (M4-to-M3): Min via (M3-to-M2): Min via (M2-to-M1): Min contact: Min polycide width: Min polycide space: Min gate length* - (N-channel): 70.7 mm2 (109,648 mils2) 0.11 mm (4.5 mils round) 0.14 mm (5.6 mils) 2 microns (bottom portion of the line) 1.7 micron 3.8 microns 0.5 micron (bottom portion of the line) 0.6 micron 1.2 micron 0.55 micron 0.65 micron 1.2 micron 0.55 micron 0.5 micron 1.95 micron 0.45 micron 0.45 micron 1.0 micron 0.45 micron 0.4 micron 1.2 micron 0.7 micron 0.65 micron 0.7 micron 0.5 micron 0.45 micron 0.17 micron 0.45 micron - (P-channel): 0.17 micron 0.17 micron SRAM cell size (array A): SRAM cell pitch (array A): 27 microns2 4 x 6.7 microns SRAM cell size (array B): SRAM cell pitch (array B): 16 microns2 3.3 x 4.8 microns *Physical gate length. - 12 - VERTICAL DIMENSIONS Layers: Passivation 2: Passivation 1: Metal 6 - cap: - aluminum: - barrier: - plugs: Intermetal dielectric 5 - glass 2: - glass 1: Metal 5 - cap: - aluminum: - plugs: Intermetal dielectric 4 - glass 2: - glass 1: Metal 4 - cap: - aluminum: - plugs: Intermetal dielectric 3 - glass 2: - glass 1: Metal 3 - cap: - aluminum: - plugs: Interlevel dielectric 2 - glass 2: - glass 1: Metal 2 - cap: - aluminum: - plugs: Intermetal dielectric 1: Metal 1: Nitride layer: Pre-metal glass: Polycide - silicide: - poly: Gate oxide: Trench oxide: N+ S/D: P+ S/D: N-well: P-epi: 0.4 micron 0.4 micron 0.04 micron 1.9 micron 0.1 micron 1.2 micron 0.4 - 1 micron 0.3 - 1 micron 0.04 micron 0.8 micron 1.2 micron 0.15 - 0.95 micron 0.5 - 1 micron 0.06 micron 0.8 micron 1.1 micron 0.25 - 1 micron 0.45 - 1 micron 0.05 micron 0.8 micron 1.2 micron 0.5 - 1.2 micron 0.4 - 0.7 micron 0.05 micron 0.6 micron 0.8 micron 0.7 micron 0.4 - 0.6 micron 0.06 micron 0.55 micron 0.03 micron 0.1 micron 40Å (approximate) 0.4 micron 0.15 micron 0.13 micron 0.8 micron (approximate) 1.7 micron - 13 - INDEX TO FIGURES PACKAGE AND X-RAY Figure 1 DIE LAYOUT AND IDENTIFICATION Figures 2 - 4 PHYSICAL DIE STRUCTURES Figures 5 - 43 COLOR DRAWING OF DIE STRUCTURE Figure 38 FUSES Figures 39 and 39a MEMORY CELL Figures 40 - 43 - ii - IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Figure 1. Package photographs and x-ray of the IBM/Motorola 750 RISC. Mag. 2.5x. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Figure 2. Whole die photograph of the IBM/Motorola 750 RISC microprocessor. Mag. 23x. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Mag. 500x Mag. 500x Mag. 320x Figure 3. Optical views of die markings. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Figure 3a. Additional die and mask markings. Mag. 500x. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Figure 4. Optical views of die corners. Mag. 100x. PASSIVATION METAL 5 METAL 6 IBM/Motorola 750 RISC CuSn BOND PAD METAL 4 METAL 3 Mag. 3000x PASSIVATION METAL 6 (FROM PAD) PASSIVATION 2 PASSIVATION 1 METAL 4 METAL 3 METAL 2 METAL 6 METAL 1 Mag. 6000x Cr BARRIER POLY GATES N+ S/D Figure 5. SEM section views of the bond pad structure. Mag. 10,000x Integrated Circuit Engineering Corporation BOND PAD METAL 5 IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation METAL 6 CUTOUT 14243 EDGE OF DIE SUBSTRATE Mag. 2500x METAL 6 34241 INTERMETAL DIELECTRIC METAL 5 METAL 4 METAL 3 METAL 2 METAL 1 Mag. 6000x Figure 6. SEM section views of the edge seal structure. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Mag. 2500x Mag. 13,000x Figure 7. SEM views of general passivation coverage. 60°. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation PASSIVATION 2 PASSIVATION 1 METAL 6 M6 PLUG METAL 5 METAL 4 IMD 4 IMD 3 METAL 3 M3 PLUG METAL 2 M2 PLUG POLY GATE METAL 1 TRENCH OXIDE N+ S/D Figure 8. SEM section view illustrating general device structure. Mag. 17,400x. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation METAL 6 M6 PLUG METAL 5 METAL 4 M3 PLUG METAL 3 METAL 2 M2 PLUG METAL 1 POLY GATE N+ S/D Mag. 7500x PASSIVATION 2 METAL 6 IMD 5 METAL 5 METAL 4 METAL 2 METAL 3 IMD 3 METAL 1 POLY GATES TRENCH OXIDE glass-etch, Mag. 8000x Figure 9. Additional SEM section views illustrating general structure. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation PASSIVATION 2 PASSIVATION 1 METAL 6 Mag. 13,000x PASSIVATION 2 PASSIVATION 1 METAL 6 TiN CAP ALUMINUM Ti BARRIER Mag. 23,000x Figure 10. SEM section views of metal 6 line profiles. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation METAL 6 Mag. 2800x, 0° METAL 6 M6 PLUG Mag. 15,000x, 60° Figure 11. SEM views illustrating metal 6 patterning. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Mag. 3000x Mag. 6000x METAL 6 Mag. 15,000x M6 PLUG Figure 12. SEM views illustrating general metal 6 integrity. 60°. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation PASSIVATION 2 METAL 6 Mag. 13,000x M6 PLUG IMD 5 METAL 5 PASSIVATION 2 METAL 6 Mag. 15,000x Ti BARRIER M6 PLUG IMD 5 METAL 5 W PLUGS Mag. 25,000x, 60° METAL 5 Figure 13. SEM views of metal 6-to-metal 5 via plugs. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation PASSIVATION 2 METAL 5 IMD 4 Mag.17,600x IMD 5 TiN CAP METAL 5 ALUMINUM IMD 4 Mag. 26,000x Figure 14. SEM section views of metal 5 line profiles. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation METAL 5 M6 PLUG Mag. 8000x Mag. 10,000x Figure 15. Topological SEM views of metal 5 patterning. 0°. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Mag. 7400x TiN CAP METAL 5 Mag. 30,000x M5 PLUG METAL 5 Mag. 15,000x M5 PLUG METAL 4 Figure 16. SEM views of general metal 5 integrity. 55°. M5 PLUG IMD 4 METAL 5 M5 PLUG IMD 4 METAL 4 IMD 3 M4 PLUG IBM/Motorola 750 RISC METAL 5 METAL 4 METAL 3 Mag. 15,000x Mag. 15,000x METAL 5 M5 PLUG DELINEATION ARTIFACT TiN CAP METAL 4 METAL 4 Mag. 26,000x Mag. 30,000x, 55° Figure 17. SEM views of metal 5-to-metal 4 vias and metal 5 plugs. Integrated Circuit Engineering Corporation M5 W PLUG IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation IMD 4 IMD 3 METAL 4 Mag. 26,000x IMD 4 TIN CAP METAL 4 ALUMINUM Mag. 52,000x Figure 18. SEM section views of metal 4 line profiles. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation METAL 4 Figure 19. Topological SEM views of metal 4 patterning. Mag. 9000x, 0°. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Mag. 11,000x TiN CAP METAL 4 Mag. 25,000x M4 PLUG METAL 3 M5 PLUG TiN CAP METAL 4 Mag. 35,000x M4 PLUG Figure 20. SEM views illustrating general metal 4 integrity. 55°. M5 PLUG METAL 4 METAL 4 IMD 3 IBM/Motorola 750 RISC METAL 5 M4 PLUG M4 PLUG METAL 3 METAL 3 Mag. 15,000x Mag. 20,000x METAL 4 IMD 3 M4 PLUG METAL 3 METAL 3 Mag. 26,000x Mag. 45,000x, 60° Figure 21. SEM views of metal 4-to-metal 3 via plugs. Integrated Circuit Engineering Corporation W PLUG IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation IMD 3 METAL 3 IMD 2 Mag. 26,000x TiN CAP METAL 3 ALUMINUM IMD 3 Mag. 52,000x Figure 22. SEM section views of metal 3 line profiles. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation M4 PLUG METAL 3 Mag. 13,000x M3 PLUG METAL 3 MISALIGNMENT Mag. 26,000x Figure 23. Topological SEM views illustrating metal 3 patterning. 0°. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Mag. 13,000x TiN CAP MISALIGNMENT REDUCED SPACING METAL 3 Mag. 30,000x M3 PLUG METAL 3 Mag. 30,000x M3 PLUG Figure 24. SEM views illustrating general metal 3 integrity. 60°. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation METAL 3 Mag. 26,000x M3 PLUG IMD 2 DELINEATION ARTIFACT METAL 2 METAL 3 Mag. 26,000x IMD 2 M3 PLUG METAL 2 M3 W PLUG METAL 2 Figure 25. SEM views of metal 3-to-metal 2 via plugs. Mag. 32,000x, 55° IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation IMD 2 METAL 2 IMD 1 METAL 1 Mag. 26,000x IMD 2 14243 METAL 2 TiN CAP ALUMINUM 2 Mag. 52,000x Figure 26. SEM section views of metal 2 line profiles. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation METAL 2 M3 PLUGS METAL 1 Figure 27. Topological SEM views of metal 2 patterning. Mag. 8000x, 0°. M3 PLUGS M3 PLUGS IBM/Motorola 750 RISC METAL 1 METAL 2 M2 PLUG METAL 2 METAL 1 POLY Mag. 13,500x Mag. 13,000x TiN CAP METAL 2 METAL 2 M2 PLUG M2 PLUG POLY METAL 1 METAL 1 POLY GATE Mag. 30,000x Mag. 32,000x Figure 28. SEM views illustrating general metal 2 integrity. 55°. Integrated Circuit Engineering Corporation TiN CAP IBM/Motorola 750 RISC METAL 2 METAL 2 M2 PLUG IMD 1 M2 PLUG METAL 1 METAL 1 TRENCH OXIDE TRENCH OXIDE P+ Mag. 26,000x Mag. 26,000x METAL 2 W PLUG METAL 1 IMD 1 METAL 1 POLY N+ TRENCH OXIDE Mag. 26,000x Mag. 30,000x, 55° Figure 29. SEM views of metal 2-to-metal 1 via plugs. Integrated Circuit Engineering Corporation M2 PLUG IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation M2 PLUGS METAL 1 POLY POLY Figure 30. Topological SEM views of metal 1 patterning. Mag. 10,000x, 0°. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation Mag. 13,500x POLY METAL 1 Mag. 22,000x POLY METAL 1 POLY Figure 31. SEM views of general metal 1 coverage. 55°. Mag. 60,000x IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation METAL 2 METAL 1 M2 PLUG Mag. 30,000x POLY GATE P+ S/D METAL 2 M2 PLUG IMD 1 Mag. 30,000x POLY GATE METAL 1 N+ S/D PRE-METAL DIELECTRIC METAL 1 TiN LINER Mag. 60,000x POLY TRENCH OXIDE Figure 32. SEM section views of metal 1 contacts. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation POLY GATES RESIDUAL TRENCH OXIDE Mag. 6500x POLY GATE POLY GATE DIFFUSION TRENCH OXIDE Mag. 10,000x Figure 33. Topological SEM views of poly patterning. 0°. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation POLY DIFFUSION Mag. 13,000x DIFFUSION POLY Mag. 47,000x Figure 34. Perspective SEM views of poly coverage. 55°. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation METAL 2 M2 PLUG METAL 1 POLY GATE P+ S/D Mag. 26,000x POLY GATE METAL 1 P+ S/D P+ S/D Mag. 52,000x Figure 35. SEM section views of P-channel transistors. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation METAL 2 M2 PLUG Mag. 26,000x POLY GATE METAL 1 N+ S/D POLY GATE SIDEWALL SPACER METAL 1 Mag. 52,000x N+ S/D GATE OXIDE Ti SILICIDE NITRIDE glass-etch, Mag. 52,000x POLY Ti SILICIDE Figure 36. SEM section views of N-channel transistors. IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation POLY Mag. 52,000x TRENCH OXIDE GATE OXIDE NITRIDE TRENCH OXIDE Ti SILICIDE glass-etch, Mag. 76,500x Mag. 800x P-EPI N-WELL P SUBSTRATE Figure 37. SEM section views of trench oxide and well structures. M5 PLUG METAL 1 M4 PLUG PASSIVATION 2 PASSIVATION 1 METAL 6 IMD5 IBM/Motorola 750 RISC M2 PLUG M3 PLUG M6 PLUG METAL 5 IMD4 METAL 4 IMD3 METAL 3 IMD2 METAL 2 IMD1 ,,,,,,,,, TRENCH OXIDE N-WELL P-WELL Ti SILICIDE N+ S/D POLY P-EPI P+ S/D Ti SILICIDE P SUBSTRATE Orange = Nitride, Blue = Metal, Yellow = Oxide, Green = Poly, Red = Diffusion, and Gray = Substrate Figure 38. Color cross section drawing illustrating device structure. Integrated Circuit Engineering Corporation PRE-METAL DIELECTRIC IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation intact, Mag. 4400x, 0° FUSES PASSIVATION CUTOUT W M5 ALUMINUM FUSE LINK ALUMINUM FUSE LINKS Figure 39. SEM views of typical fuses. passivation removed, Mag. 4400x, 0° passivation removed, Mag. 3400x, 60° CUTOUT 1442443 SECTIONING ARTIFACT CUTOUT METAL 5 METAL 5 IMD IBM/Motorola 750 RISC PASSIVATION 2 M5 TUNGSTEN ARTIFACT METAL 4 METAL 3 M5 TUNGSTEN METAL 2 Mag. 5000x Mag. 9000x IMD 5 METAL 5 M5 TUNGSTEN METAL 4 Mag. 19,000x Mag. 16,000x Figure 39a. SEM section views of a metal 5 fuse. Integrated Circuit Engineering Corporation M5 TUNGSTEN IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation VCC “PIGGYBACK” WORD LINES BIT CONTACTS metal 2 GND metal 1 POLY WORD LINES poly Figure 40. Perspective SEM views of SRAM cell array (Array A). Mag. 6500x, 55°. GND BIT VCC IBM/Motorola 750 RISC GND “PIGGYBACK” WORD LINE CONTACTS BIT BIT CONTACT “PIGGYBACK” WORD LINE metal 3 metal 1 WORD LINE GND GND VCC N+ P+ SELECT GATES BIT P-WELL metal 2 N-WELL poly Figure 41. Topological detail SEM views of the SRAM cell (Array A). Mag. 12,000x, 0°. Integrated Circuit Engineering Corporation BIT VCC IBM/Motorola 750 RISC Integrated Circuit Engineering Corporation “PIGGYBACK” GND WORD LINE GND VCC BIT CONTACTS metal 2 metal 1 WORD LINES poly Figure 42. Perspective SEM views of SRAM cell (Array B). Mag. 8000x, 55°. IBM/Motorola 750 RISC BIT VCC GND BIT metal 3 “PIGGYBACK” WORD LINE metal 1 WORD LINE RESIDUAL METAL 1 LINER GND BIT SELECT GATES N+ (GND) P+ (VCC) BIT N-WELL P-WELL metal 2 poly Figure 43. Topological detail views of the SRAM cell (Array B). Mag. 13,000x, 0°. Integrated Circuit Engineering Corporation VCC