System and method for evaluating image placement on pre-distorted masks
US5917932A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 24, 1997 |
| Grant date | Jun 29, 1999 |
| Priority date | — |
| Expiry date | Jun 24, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/2817
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Process steps are provided to analyze image placement on a pre-distorted lithographic mask produced by a lithographic system. Obtain metrology data, form a reference array equal to the design coordinates of the metrology sites. Align the metrology data grid coordinate system to remove rigid body components from the metrology data offsets. Parse the metrology data into one or more correction areas. If the mask is to have its disposition provided according to the statistics of the residual errors in the correction areas, then compute the statistics and compare them to the specifications. Otherwise concatenate the local reference arrays summed with their corresponding correction area center coordinates to form reference mark design location arrays. Concatenate temporary arrays with the mask offsets free of pre-distortion into an array of mask offsets corresponding to desired disposition areas and compute statistical distribution of residual errors in array(s) of mask offsets for disposition. Compare statistical distribution of residual errors determined during computation with the specified statistical distribution of the mask disposition areas to accept or reject the mask.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.