The subject invention provides a 
correction method for 
design data or 
mask data comprising the steps of:(i) carrying out PPC of 
design data or 
mask data;(ii) exposing and developing a 
resist with an evaluation 
mask including a critical pattern which becomes critical in a process, 
etching a circuit material using the 
resist having been developed, and measuring pattern sizes of the developed 
resist and the etched circuit material; (iii) extracting parameter numerical condition for preventing the 
design data or the mask data from being critical after OPC or PPC, as a rule or as a model based on the pattern sizes of the resist and the circuit material; (iv) extracting a critical pattern with a parameter not satisfying the foregoing rule or the model from the design data or the mask data; and (v) correcting the critical pattern.With this method, the present invention provides such as a validation / 
correction method for design data or mask data by which a pattern which becomes critical in a process is extracted in advance so that the pattern can be corrected. Consequently, the process spec is achieved in a short period of time after OPC or process 
proximity effect correction (PPC).