SEMICONDUCTOR DEVICE AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To form a mask alignment mark part comprising a deep trench formed on the same substrate as that of a semiconductor device by forming a polycrystal silicon embedded in a deep trench in an optimal depth, in order to increase a signal strength at the time of the alignment and to improve an accuracy of the mask alignment.

SOLUTION: Forming a groove 150 formed on an upper part of the trench of the alignment mark part 300 deeper than the surface of the semiconductor substrate increases the signal strength of the alignment with the alignment mark used. A method for varying an etching speed at the time of forming the groove with the impurity injection is applied to the method for forming the groove 150 deeper than the surface of the semiconductor substrate.

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