This paper presents assessment criteria for Process FMEA (Failure Mode and Effect Analysis) for assembly process in semiconductor. In this paper, we analyzed the major issues when evaluating RPN (risk priority ranks) evaluation of FMEA, the RPN evaluation criteria were redefined. This criterion is applied to the LED and semiconductor assembly process and effectiveness is verified. The main problem when evaluating RPN ratings did not apply to kind of products. Evaluation criteria observed ambiguity between evaluators. When assessing the seriousness, existing standards were analyzed and divided into 10 levels. The ratings were redefined. Occurs, in order to improve the problem evaluation were considered to reduce the error evaluation based on the details of the existing items. Detection evaluation problem, in order to improve the ambiguity of the grading was separated on the details of the existing entries.