Method and apparatus for personalization of semiconductor
OwnerTorbjorn Sandstrominventor
Life of this patent
Estimating the term…
Abstract
A system for making small modifications to the pattern in standard processed semiconductor devices. The modifications are made to create a small variable part of the pattern against a large constant part of the same pattern. In a preferred embodiment the exposure of the variable and constant parts are done with the same wavelength in the same combined stepper and code-writer. The invention devices a way of writing variable parts of the chip that is automatic, inexpensive and risk-free. A system for automatic design and production of die-unique patterns is also shown.
Claims11
1-18. (canceled)
A control system for controlling a stepper to personalize at least one die on a wafer characterized by
- a stepper control system initiating the exposure of the exposure field containing the die,
- a codewriter control system compiling information about the programming for a particular die,
- and a code rasterizing unit for creating a hardware format to be fed to an spatial light modulator (SLM) for a particular die.
A design block for a chip with a chip-unique information, such as a serial number or hidden cryptographic key, characterized in that it comprises
- a layout block describing the layout of the constant part of the block,
- a control block specifying the type of code to be written and the placement of the code,
- and a data block, where the contents of the block is described, e.g., by a reference to a database or to a sequence of instruction.
A method for personalization of a die on a wafer comprising
- exposing to the die a constant part of a pattern, said constant part being used for exposing at least one other die,
- and exposing to the same die a variable part of a pattern,
- said variable part differing from the corresponding variable part of another die on the wafer, and preferably being a die-unique information, such as a serial number or hidden cryptographic key.
A method for fast correction of position errors in a pattern generator using an analog spatial light modulator (SLM) comprising the steps of
- measuring the stage position error compared to the correct position,
- convolving the bitmap loaded into the SLM by a convolution kernel, whereby said kernel is selected or modified in dependence of the measured position error in order to correct said position error.
Dependencies are inferred from the claim text.