Generic terms and special packaging


Ceramic package

COB (Chip-On-Board)

Bare silicon chip without a package and affixed directly to the circuit board. Use in cost sensitive (ie cheap) applications. Above is probably from a commodity wrist watch. There seem to be two types:

  • Epoxy blob (below type): die is placed on board, bonded, and then covered with a blob of epoxy. The most common type
  • Upside down dies (above type): likely WLCSP with underfill. Basically a BGA where there is no encapsulant on the die and solder balls are attached directly to bond pads (see BGA below for example of this sort of thing)
  • Flexible circuit: these are common in the line drivers on LCD screens

Example showing wire bonding to PCB:

COF (Chip-On-Flex)

A variation of COB, where a chip is mounted directly to a flex circuit

COG (Chip-On-Glass)

A variation of COB, where a chip is mounted directly to a piece of glass - typically an LCD

CSP (Chip Scale Package)

Package no more than 1.2x the size of the silicon chip.

LTCC (Low Temperature Co-fired Ceramic)


MCM (Multi-Chip Module)

Several dies integrated into one package. Considerable variety.

Flip chip

A package where the die is mounted upside down. Usually this implies BGA or similar package.

Ceramic BGA example

Had thermal paste to improve conductivity:


After cleaning:


When most solder balls are removed on the bottom looks like this:


After dissolving some of the epoxy on the top:

package_some_top.jpg package_some_side.jpg

As can see in above though there was still some underfill left. Next pictures show the epoxy/underfill not completley dissolved and some gunk (solder paste?) left in the center as well as some sort of spacer:

package_some_nodie.jpg package_some_ga.jpg

die_some.jpg die_some_closeup.jpg


Usually refers to a chip for testing DNA

TCSP (True Chip Size Package), TDSP (True Die Size Package)

Package is the same size as silicon.


carrier/start.txt · Last modified: 2013/11/16 08:00 by mcmaster
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