Multi Chip Mask Die Rotation & Mirror to Minimize Lens Exposure Aberrations on Chip Performance
Original Publication Date: 2004-Dec-22
Included in the Prior Art Database: 2004-Dec-22
Integrated Circuit (IC) chip characteristics (ex: speed, performance, timing, etc.) vary based on the optical distortion of stepping imaging systems and semiconductor processes used in the wafer manufacturing line. This generally takes on the form of radial distortion, causing differences based on distance from center of the lens and/or wafer. Current wafer manufacturing methods employ identical orientation of chips on a wafer (and multi chip reticles / masks). This has a disadvantage when multi-chip reticles are employed, because lens distortion and manufacturing processes are known to effect each chip within the reticle differently. This manifests itself as a lack of consistency between identical x,y locations on a chip. For example, a four chip reticle produces four uniquely performing chips. It is an advantage for all manufactured chips to perform identically. This invention will describe a means to achieve better consistency with currently available lenses and processes.