This picture is from [here][1] (`A` and `B` letters are irrelevant for this question). A chip-and-pin card like Visa Electron has a contact pad like this on its face side:

   [![enter image description here][2]][2]

Underneath the contact pad is the chip which has electrical connection with the contact pad. The pictures I found so far suggest that it's a single module - the chip is mechanically united with the contact pad and is then installed into a plastic card.

The contact pad is perhaps ten millimeter wide and ten millimeters long and so much larger than the chip surface. When a card is being bent the contact pad also bends and this most likely causes the chip casing to bend which causes mechanical stress of the chip. Mechanically stressing a chip doesn't sound like a good idea.

How is this problem addressed? Does merging a large contact pad with a smaller chip into a single module make the whole assembly more reliable or more fault-prone?


  [1]: http://electronics.stackexchange.com/q/34074/3552
  [2]: https://i.sstatic.net/rYYei.jpg