Packaging and assembly

What is the typical diameter of wires used in wire bonding?

  1. AAbout 1 to 2 mm
  2. BAbout 1 nm
  3. CAbout 15 to 50 µm
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Answer: C. About 15 to 50 µm

Bonding wires are very fine metal wires about 15 to 50 µm in diameter, often thinner than a human hair (about 70 µm). High-current power devices also use thick aluminum wires of several hundred micrometers.

  • A. 1 mm or more is far too thick to bond to chip electrodes.
  • B. 1 nm is the width of a few atoms and cannot form a wire.
  • C. Correct. They are wires of a few tens of micrometers, thinner than a hair.
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More Packaging and assembly questions

  1. What is the packing format called in which surface-mount ICs are placed one by one in pockets in a tape and wound up, to be fed to placement machines?
  2. What is the main advantage of surface mounting compared with inserting leads into holes in the PCB?
  3. In leadframe packages, what is the main purpose of plating the exposed leads with tin (Sn)-based plating?
  4. In reflow with lead-free solder (Sn-Ag-Cu), which is closest to the peak temperature that parts experience?
  5. Which dicing method, with almost no kerf loss, focuses a laser inside the wafer to create a modified layer and then separates chips by stretching the tape?