Si Chip Electrical Contact - PowerPoint PPT Presentation

1 / 18
About This Presentation
Title:

Si Chip Electrical Contact

Description:

Fig. 3.26: A picture of a TAB film with the Cu pattern, as well as the holes in ... vacuum deposition, sputtering, soldering, gluing, wire bonding, TAB, and flip chip ... – PowerPoint PPT presentation

Number of Views:260
Avg rating:3.0/5.0
Slides: 19
Provided by: perohl
Category:

less

Transcript and Presenter's Notes

Title: Si Chip Electrical Contact


1
Si Chip Electrical Contact
  • Wire bonding
  • Tape Automated Bonding (TAB)
  • Flip chip
  • Planar bonding

2
Wire Bonding
  • Ultrasonic
  • Thermo-compression
  • Thermosonic
  • Geometry Types
  • Ball - wedgeShown in illustration
  • Wedge - wedge

3
Wire Bonding
From Small Precision Tools
4
(No Transcript)
5
Tape Automated Bonding (TAB)
  • Fig. 3.26 A picture of a TAB film with the Cu
    pattern, as well as the holes in the film for
    excising the circuits, and the sprocket holes for
    moving the film during processing.

6
Tape Automated Bonding (TAB)
  • Interconnection by metallized flexible polymer
    tape

7
Tape Automated Bonding (TAB)
  • Connection made in two steps
  • Inner Lead Bonding
  • Connecting tape to chip
  • Outer Lead Bonding
  • Connecting tape to substrate
  • Connection made by thermocompression

8
TAB, continued
  • Standard process
  • Fabrication of gold bumps (Fig. 3.28)
  • Deposition of contact/barrier metals
  • Photolithography
  • Electroplating
  • Strip and etch barrier metals

9
TAB, continued
  • Fig. 3.27 The main steps in TAB processing.

10
Advantages of TAB
  • High packaging density
  • Can contact chips with gt1000 I/O
  • Excellent electrical properties (high frequency)
  • Robust mounting
  • Pre-testable (contrary to COB)
  • Gold bumps give hermetic seal to chip
  • Gang bonding gives high yield, is less time
    consuming than wirebonding
  • TAB film can be used as daughter board

11
Disadvantages of TAB
  • Non-standard wafer processes
  • Special custom design film for chip
  • Needs special machine/tool for OLB
  • Demanding repair
  • Low availability of std. chips and TAB service
  • Little standardization

12
Flip chip
  • Active face of chip is flipped towards substrate
  • Substrate pads are identical to chip pads
  • Area array connections possible
  • All connections done simultaneously
  • Smallest possible footprint (11)
  • Short interconnections
  • Low inductance and resistance
  • Excellent electrical properties
  • Little flexibility
  • Change of chip pad configuration implies redesign
    of substrate
  • Small, but increasing amount of interconnections
    are flip chip
  • To be dealt with in much more detail

13
Flip Chip, history
  • Introduced by IBM 1962
  • Flip chip has been used for decades, but with
    little impact
  • Wire bonding is far more common
  • Flip chip technology has not been considered
    mature
  • The industrial infrastructure has been small
  • The market share of flip chip connections is
    believed to increase significantly
  • Wire bonding will remain dominating for many
    years
  • Flip chip especially for advanced packaging

14
Flip Chip consists of
  • Chip
  • Si, GaAs, etc.
  • Substrate
  • Ceramic, organic, dielectic-covered metal,
    silicon, etc.
  • Interconnection system
  • Metallization on chip and substrate pads
  • Chip (or substrate) bumps
  • Bonding material
  • Underfill encapsulant

15
Different Flip Chip technologies
  • Flip chip is not standardized!

From C. Lee, ESTC 2006, Dresden
16
Flip Chip, continued
  • Advantages
  • Highest packing density
  • Excellent hi freq. properties
  • Up to 10 000 I/O
  • Disadvantages
  • Very difficult placement and reliable
    solder/cleaning
  • Lack of thermal flexibility

17
Planar Bonding with Adaptive Routing
  • Fig. 3.32 Planar bonding with laser-assisted
    adaptive conductor routing. The top two figures
    a) and b) show a substrate cross section with
    details of the mounting of the chip in an etched
    through-hole. Figure c) shows the conductor
    layers and polyimide insulation on top of the
    substrate. The bottom figures show an exploded
    view of all the layers.

18
End of Chapter 3 Materials and Basic Processes
  • Important issues
  • Materials
  • Distinguish between metals, ceramics, glasses and
    plastics
  • Important mechanical and thermal parameters like
    modulus of eleasticity, thermal expansion
    coefficient and thermal conductivity.
  • Important electrical parameters like dielectric
    constant and resistivity or conductivity
  • Have a basic understand of the importance and
    value of the most important materials parameter,
    and why they are important for the use of the
    specific material in specific applications.
  • For instance knowing the electrical conductivity
    of copper or thermal conductivity of epoxy within
    an accuracy of 25
  • Basic processes
  • Lithographics, screen and stencil printing,
    etching, plating, vacuum deposition, sputtering,
    soldering, gluing, wire bonding, TAB, and flip
    chip
  • Other basic processes described in other
    chapters, like surface mount technology
  • Questions and discussions?
Write a Comment
User Comments (0)
About PowerShow.com