Semiconductor device and method of manufacturing same
According to this invention, a semiconductor device has an upper surface on which an external connection electrode is formed and a lower surface which opposes the upper surface and is in a mirror surface state. A roughened region roughened by laser marking is formed at part of the lower surface. The roughened region includes a product information mark of the semiconductor device itself. The product information mark is printed by laser marking. The number, size, shape, and layout position of the roughened regions are decided to make it possible to, when the lower surface is irradiated with light, read the product information from the difference in light reflectance between the roughened region and mirror-finished region.
1. A semiconductor device which has a first surface on which an external connection electrode is formed and a second surface which opposes the first surface and is in a mirror surface state, the device comprising:
a first roughened region obtained by roughening a first part of the second surface by providing a first plurality of craters each including a first recessed portion and a first projecting portion around the first recessed portion by laser marking and forming one or more marks included in characters that include product information of a semiconductor device, the first plurality of craters being provided so that the distance along the second surface between adjacent first craters is no more than a maximum width of the first craters along the second surface,
a second roughened region obtained by roughening a second part of the second surface by providing a second plurality of craters each including a second recessed portion and a second projecting portion around the second recessed portion by laser marking, the second plurality of craters being provided so that the distance along the second surface between adjacent second craters is no more than a maximum width of the second craters along the second surface,
wherein the second roughened region has an adjusting function for adjusting a difference in light reflectance on the second surface by adjusting the number, size, shape and layout position of the second craters when the second surface is irradiated with light.
2. A device according to claim 1 , wherein in each of the first plurality of craters, a difference between a bottom portion of the first recessed portion and a top portion of the first projecting portion is 1 to 10 μm.
3. A device according to claim 1 or 2 , wherein adjacent first craters of the first plurality of craters do not overlap.
4. A device according to claim 1 or 2 , wherein the product information includes an index mark of the semiconductor device itself, which is formed by laser marking.
5. A manufacturing method, wherein after a semiconductor device cluster including a plurality of semiconductor devices of claim 4 is prepared, the semiconductor device cluster is split into a predetermined size to manufacture the semiconductor device.
6. A device according to claim 1 , wherein the number, size, shape, and layout position of the first plurality of craters are decided to make it possible to, when the second surface is irradiated with light, read the one or more marks formed on the first roughened region.