1. Chapter 8: Hybrid Technology and Multichip Modules
Hybrid = mixture, i. e.: Components and wiring integrated on the substrate. Picture shows a thin film hybrid for seismic electronics.
The course material was developed in INSIGTH II, a project sponsored by the Leonardo da Vinci program of the European Union
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

2. Types of Hybrids and Multichip Modules
Thick film technology
High temperature thick film hybrid technology
Polymer thick film hybrid technology
Thin film technology
Conventional thin film technology (one conductor layer)
Multilayer thin film technology
Multichip modules:
Multilayer ceramic (MCM-C) (C for ceramic)
Multilayer thin film (MCM-D) (D for deposited)
Multilayer fineline circuit boards (MCM-L) (L for laminated)
Please also confer to Chapters 3 and 5 for basic processes
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

3. High Temperature Thick Film Technology
Important substrate properties
Dimensional stability
Good adhesion
High thermal conductivity
Thermal compatibility with components
High electrical resistivity
Low dielectric constant (not satisfied in alumina)
Low dielectric loss tangent
Good machinability (not satisfied in ceramics)
Low price
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

4. Screen Printing and Stencil Printing
Fig. 3.11: Screen printing: a) and b): Printing process, c) and d): Details of the screen
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

5. High Temp Thick Film, continued
Practical materials:
Alumina
Aluminium nitride
(Beryllia)
(Silicon carbide)
Table 8.1: Properties of substrate materials for hybrid technology. P: Plastic In: Insulator
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

6. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Conductor Materials
Composition
Functional element (metal particles)
Binder (glass particles)
Solvents
Desired properties
High electrical conductivity
Good adhesion to substrate
Good solderability
Good bondability
Low price
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

7. Conductor Materials, continued
Practical functional element
Gold
Ag/Pd
Ag/Pt
Copper
Table 8.2 Properties of thick film conductor systems
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

8. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Thick Film Resistors
Important properties
Large range of resistor values
High stability
Low thermal coefficient of resistivity
Low voltage coefficient of resistivity
Low noise
Materials
Oxides of ruthenium
Oxides of iridium, rhodium, osmium
Sheet resistance: ohms/sq
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

9. Properties of Thick Film Resistors
Table 8.3: Typical properties of thick film resistors.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

10. Termination of Thick Film Resistors
Fig. 8.2: Thick film resistor with termination
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

11. Insulators / Dielectrics
Desired properties:
High insulation resistance
High breakdown field
Low dielectric constant (insulation)
Suitable/high dielectric constant (dielectric)
Low temperature coefficient (dielectric)
Low voltage coefficient (dielectric)
Low loss tangent
Little porosity
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

12. Insulators / Dielectrics, continued
Materials
Aluminium oxide/glass (insulator)
Ceramics/glasses as for capacitors (dielectric)
Please also see Chapter 4
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

13. Insulators / Dielectrics, continued
Table 8.4: Typical properties of printed and discrete capacitors.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

14. Production Process for High Temperature Thick Film Technology
Layout and photolithographics
CAD work
Photo or laser plotting of master films
Printing screens made with master films
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

15. Production process, continued
Printing process
Printing
Drying at °C
Firing at °C
Fig 8.1: Typical temperature profile for thick film firing.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

16. Production process, continued
Testing and laser trimming
Initial value targeted % below specified value
Laser trimming to increase resistance within ± 0.5 or ± 1.0 %
Fig. 8.4: Probe card for testing of thick- and thin film hybrid circuits. Coaxial probes are used for high frequency signals.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

17. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Laser trimming a) b) c)
Fig. 8.5: Laser trim cut forms: a): L-cut, the most common b): Top hat plunge cut c): Digital trimming, which is most used for high precision thin film resistors
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

18. Laser trimming, continued
Fig. 8.6: Laser trimmer for thick film hybrid circuits, ESI Model 44.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

19. Production process, continued
Fig. 8.7: Process flow for mounting of thick film hybrid circuits based on: a): Naked ICs and gluing of discrete components.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

20. Production process, continued
Fig. 8.7: Process flow for mounting of thick film hybrid circuits based on: b): Soldering of packaged ICs and discrete components.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

21. Polymer Thick Film Technology
In polymer thick film hybrid technology (PTF) conductors, resistors and insulating layers use a polymer matrix instead of glass matrix, and these are made in several layers on ordinary printed wiring board laminates, flexible substrates and injection moulded plastic materials that can serve as combined printed circuits and chassis.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

22. Polymer Thick Film, continued
Advantages
Low price
Simple processes
Fast production throughput
Well suited for repair/modification
Printed resistors possible
Additive technology
Printed wiring boards for substrates
Specialities:
Membrane switch panels
Contacts
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

23. Polymer Thick Film, continued
Limitations
Satisfies only moderate environmental requirements
Low/moderate complexity
High sheet resistivity in conductors
Special design rules
Limited solderability
Limited shelf life for pastes
Limited availability
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

24. Polymer Thick Film, continued
Fig. 8.8: Polymer Thick film (PTF) carbon technology, for:
a): Keyboard contacts.
b): Contacts of LCD displays.
c): Sliding potentiometer.
CPTF means carbon type PTF.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

25. Polymer Thick Film, continued
Materials
Matrix: Thermosetting /thermoplastic polymer
Conductor: Ag, Cu, C
Solvents
Additives to adjust consistency
Ceramic or other additives
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

26. Polymer Thick Film, continued
A typical process
The starting material is a laminate with a single sided etched conductor pattern in Cu foil
1. Cleaning of the board
2. Printing of PTF insulation layer, 2 prints, drying in between
3. Drying
4. UV curing
5. Printing of PTF conductor
6. Drying
7. Curing in IR in-line furnace
8. Chemical plating of metal (Optional)
9. Printing of top layer
10. Drying
11. Curing in IR furnace.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

27. Polymer Thick Film, continued
Fig. 8.9: Membrane switch panel, principle.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

28. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
PTF, continued
Fig. 8.10: PTF based printed wiring boards: a): Single sided board with PTF for one complete conductor layer on top of one Cu foil conductor plate. b): Double sided, through hole plated board with one extra PTF conductor layer on each side. c): Double sided board through hole printed PTF conductor, instead of through hole plating. d): PTF resistor
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

29. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Thin Film Technology
Substrate materials
Alumina, glass, silicon
Conductor materials
Gold, aluminium
Resistor materials
NiCr (Chrom nickel), Ta2N (Tantal nitride)
Insulation/dielectrics/passivation materials
SiO2 (Silicon dioxide), SiN3 (Silicon nitride), Al2O3 (Aluminium oxide), Ta2O5 (Tantal oxide)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

30. Thin Film Technology, continued
Table 8.5: Properties of thin film resistors. (d: skin depth. Evap: Vacuum evaporation. Sp: Sputtering)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

31. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Thin Film Processing
Photolithography and etching
Vacuum evaporation
Sputtering
Plating
Oxidation
Fig. 8.11: Process flow for production of thin film hybrid circuits.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

32. Vacuum Deposition and Sputtering
Vacuum evaporation:
Chamber evacuated to less than 10-6 Torr
Resistance heating
Metal evaporation
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

33. Other Methods for Deposition of Conducting or Insulating Films
DC Sputtering (Fig a)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

34. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Deposition, continued
Radio Frequency AC Sputtering (Fig.3.13.b)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

35. Thin Film Processing, continued
Fig : Structure of thin film resistor with gold termination.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

36. Thin Film Processing, continued
Fig. 8.13: Thin film microwave circuit, schematically.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

37. Thin Film Processing, continued
Fig. 8.14: Thin film transistors, structure.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

38. Thin Film Processing, continued
Circuit production
Glueing
Wire bonding
Testing
Packaging in hermetic (metal) box
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

39. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Wire Bonding
Ultrasonic
Thermo- compression
Thermosonic
Geometry Types
Ball - wedge: Shown in illustration
Wedge - wedge
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

40. What are Multichip Modules?
A multichip module (MCM) is a single unit (“package”) containing two or more chips and an interconnection substrate which function together as a system building block.
MCM-L MCM-C MCM-D
From:
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

41. Types of Multichip Module Substrates
3 basic multichip modules:
MCM-D deposited thin-film multilayers (D for deposited)
MCM-C thickfilm or cofired ceramic technology (C for ceramic)
MCM-L based on organic laminate technology (L for laminated) derived from conventional PWB technology (also known as chip-on-board, COB)
Pictures from:
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

42. Multilayer Thin Film – MCM-D
Process
1. Spinning polyimide insulation
2. Deposition Al metallization
3. Photolithography, wet etch
4. Spinning polyimide
5. Etching vias
6. Repetition steps 1 - 5
7. Metallization and etching of metal
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

43. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-D, continued
Fig a): AT&T´s structure for multilayer thin film. Please also see also Figure 2.13.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

44. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-D, continued
Fig b): Cross section of Raychem´s High Density Interconnect (HDI) schematically and observed through microscope.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

45. MCM-D, continued
Fig. 8.16: Elements of the design rules for Raychem´s HDI technology
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

46. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-D, continued
Fig. 8.17: Characteristic impedance for Raychem´s HDI as function of the ratio between conductors width and dielectric thickness.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

47. MCM-D, continued Fig. 8.18a): Dissipation factor for Raychem´s HDI
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

48. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-D, continued
Fig b): Typical attenuation, as function of frequency, for Raychem´s HDI. Even at 10 GHz attenuation in the conductor metal dominates.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

49. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-D, continued
Advantages
Optimal thermal match when Si substrate
High thermal conductivity in Si: 150 W/°C x m
Termination resistors and decoupling capacitors integrated in substrate
Compatibility with:
Wire bonding
TAB
Flip chip
Very high conductor density/package density
Very good high frequency properties
Good mechanical properties of Si substrate
High reliability
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

50. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-D, continued
Disadvantages:
Low availability and high cost
Polyimide is hygroscopic
Important properties change
Reliability problems
Hermetic encapsulation necessary
Immature technology
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

51. Multilayer Ceramic Modules - MCM-C
Materials
Alumina
Aluminium nitride
Pioneer: IBM
Fabrication: Green Tape process
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

52. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-C, continued
Fig. 8.19: Production process for multilayer ceramic, schematically.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

53. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-C, continued
Advantages
High thermal conductivity
Low TCE, match to Si, GaAs, SMDs
Compatible to flip chip, wire bonding, TAB, SMD soldering
Control over characteristic impedance
Hermetic encapsulation possible, high reliability
Many conductor layers, high yield
Edge contacts, etc. brazed on
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

54. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-C, continued
Disadvantages
Low electrical conductivity in inner layers (Rsq ~ 15 mOhm/sq)
High dielectric constant, r ~
High startup cost for custom specific circuits
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

55. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-C, continued
Fig. 8.20: Combination of naked chips in cavities and soldered, packaged SMD components on multilayer ceramic module
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

56. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-C, continued
Fig a: Characteristic impedance for typical geometries and dimensions, Al2O3-based multilayer ceramic: a): Open microstrip.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

57. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-C, continued
Fig b: Characteristic impedance for typical geometries and dimensions, Al2O3-based multilayer ceramic: b): Buried microstrip.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

58. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-C, continued
Fig c: Characteristic impedance for typical geometries and dimensions, Al2O3-based multilayer ceramic: c): Stripline.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

59. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
MCM-C, continued
Table 8.6: Properties of alumina-based high temperature multilayer ceramic.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

60. Low Temperature Multilayer Ceramic Modules - LTMCM-C
Substrate materials
Glasses, glass ceramics:
Mullite, corderite, lead borosilicate glass...
Conductors
Gold, silver, AgPd
Resistors
Similar to thick film
Properties: Table 8.7.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

61. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
LTMCM-C, continued
Table 8.7: Electrical and physical properties of low temperature multilayer ceramic. a): Electrical properties.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

62. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
LTMCM-C, continued
Table 8.7: Electrical and physical properties of low temperature multilayer ceramic. b): Resistor Performance - Resistance and TCR.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

63. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
LTMCM-C, continued
Table 8.7: Electrical and physical properties of low temperature multilayer ceramic. c) Physical properties.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

64. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
LTMCM-C, continued
Advantages
Low process temperature
Most process steps can be done in high temperature thick film production line
Flexibility in conductor materials, low sheet resistivity
Plating not necessary for bonding
Screen printed resistors
Low er dielectric materials
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

65. Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
LTMCM-C, continued
Disadvantages
High costs
Low thermal conductivity
Brittle materials
Low availability
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

66. Power Electronic Modules
Challenges
Spread the heat, reduce thermal resistance
Reduce thermal stress
Provide electrical insulation for ~ 2.5 kV
Design for EMC, reduce L
Higher integration "smart power”
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

67. Power Electronic Modules, continued
Technologies
Polymer on metal
Thick film
Plated ceramic substrate
Direct Copper Bonding (DCB)
Plasma sprayed dielectric on metal base
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

68. Power Electronic Modules: Direct Copper Bonding
Fig a): The coefficient of thermal expansion for direct copper bonding (DCB) substrates with a layer of 0,6 mm alumina sandwiched between Cu layers of various thicknesses as given in the figure. b): The number of thermal cycles to fracture for DCB substrates with varies Cu thickness. The cycles were in the temperature interval °C.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

69. Direct Copper Bonding, continued
Fig. 8.23: Power electronic module [Toshiba data sheet]. The substrate (top) is DCB with AlN insulation. It is soldered to a heavy Cu plate, environmentally protected with silicone gel and mounted in a plastic package with heavy screw terminals. Each of the transistor chips and diode chips conducts up to 50 A current.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

70. Combination Technologies
Multilayer thin film - on - multilayer ceramic
Fig. 8.24: High performance modules made in a combination of multilayer thin film and multi layer ceramic technology: a): NEC Corporation computer SX-3 using flop TAB carrier on thin film and alumina based substrate. b): IBM Enterprise System/9000 packaging hierarchy using flip chip, polyimide/copper thin film on 63 layers glass ceramic substrate. a) b)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

71. Combination Technologies, continued
Thin film - on - thick film (ame, Horten). Fig.8.25:
1. Alumina substrate.
2.a,b,c,d: Printed conductor on first layer.
3. Printed dielectric film.
4. Optional compensation printed in vias.
5.a,b,c: Printed conductor on second layer.
6. Glass based dielectric.
7. a,b,c,d: Tantalum nitride resistive layer.
8.a,b,c,d: Molybdenum diffusion barrier.
9.a,b,c: Thin film gold lines.
10. Via hole between thin film and thick
film conductive layer.
11. Contact area in thick film. Gold-
platinum or gold-palladium.
12.a,b: Resistor in thin film made by
selective etching in thin film structure
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules

72. End of Chapter 8: Hybrid Technology and Multichip Modules
Important issues:
Thick film technology:
Understand the basic material considerations:
Substrate materials:
Thick film pastes
Understand the basic manufacturing steps:
Process flow diagrams from printing to final test
Chip-and-wire or SMD component assembly
Distinguish between High Temperature and Polymer Thick Film Technologies
Thin Film Technology
Substrates: Ceramic, glass or silicon
Thin film conductors, resistors and dielectrics
Process flow diagrams from deposition to final test
Hybrid Multichip Modules
MCM-D and MCM-C: Basic process steps
Combination technologies
Applications with special requirements
Cost versus performance optimisation or compromise
Questions and discussions?
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules