In fact, CPUs are basically not square anymore. Most of them are rectangles. This is related to the internal layout and wiring of the chip. However, rectangles and squares are similar. As for why they are not other shapes, this is actually a math problem.
AMD’s latest Regardless of whether it is CPU Die or I/O Die, the Ryzen processor is rectangular.
Silicon wafers without circuits
It is known that processor chips are all made and cut on a silicon circle of a certain size, and circuits around the cutting line cannot be made, so The shorter the total length of the dicing line, the smaller the wasted area of the wafer. If you want to make full use of the area of the wafer, it is actually best to cut the wafer into regular hexagons. The dicing knife used in the wafer-cutting equipment is adhesive. A very thin disc knife with diamond particles, its thickness is only 1/3 of a human hair. Cut each IC chip on the wafer to form a core Die. However, this blade can only run in straight lines, six sides The complicated shape of the shape cannot be made.
The use of regular hexagons for wafers is much higher than quadrilaterals.
The practical and feasible only can be cut into triangles, parallelograms and rectangles. The best solution of these three is the rectangle. Chip When the size is small, the utilization rate of the square to the wafer will be higher, but when the chip reaches a certain area, the aspect ratio can be adjusted appropriately to make it rectangular, which can make better use of the wafer area, so the current chip Both are square and rectangular. These are the result of cost calculation and the compromise of existing cutting technology.
Intel’s 10nm Ice Lake processor wafer