Archived posting to the Leica Users Group, 2001/03/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 04:20 PM 3/26/01 -0500, you wrote: >> Almost all the production CCDs have defective "dead" >> pixels, and - sort of like cutting a diamond - Kodak >> would cut up the wafer to produce the most efficient >> mix of usable chips. > >I don't believe that's quite right. Wafers have a number of the 'dies' on a >single wafer, typically in an XY grid pattern, like a checker board. Some >of these individual dies typically do have defects. Each of the individual >dies has what's called 'bond out pads', which are used to connect the wires >between the die and the chip carrier (typically ceramic or plastic mounting >holder that has the larger pins on it that goes into the ciruit board). > >The size of the individual die, is the size of the individual die...you do >not get a larger usable array by, say, cutting the wafer such that four of >the dies are together...they would have gaps bewteen the dies, and bonding >to the pads between the dies would be most impossible, especially for an >imaging sensor...you would have to cross over the image path. > >Also, you can't cut into the middle of a die, there is no place to bond out >to then... I know it's quite technical, but I believe you relayed the story >a little off kilter. Whomever this is... (Austin?) is correct. Jim