Patent ID: 7741221

Claim:
A method for forming a semiconductor device, the method comprising: providing a plurality of features in a layout; selecting critical features from the plurality of features; determining a plurality of first distances between each of the critical features and any of the plurality of features; placing a first short-range dummy etch feature in the layout at a first distance from a first critical feature when one of the plurality of first distances is no greater than a predetermined distance, whereby placing the first short-range dummy etch feature is performed to change feature density near one of the plurality of the critical features; determining a plurality of second distances between each of the critical features and the first short-range dummy etch features; and placing a second short-range dummy etch feature in layout at a second distance from a second critical feature when one of the plurality of the second distances is no greater than the predetermined distance, wherein the second distance is greater than the first distance.