Contactless method for measuring total charge of an oxide layer on a semiconductor wafer using corona charge

The present invention generally relates to testing a semiconductor wafer and, more particularly, to measuring a total charge of an insulating layer of the semiconductor wafer using corona charge. A method of measuring total charge of an insulating layer on a semiconductor substrate includes applying corona charges to the insulating layer and measuring a surface photovoltage of the insulating layer after applying each of the corona charges. The charge density of each of the corona charges is measured with a coulombmeter. A total corona charge required to obtain a surface photovoltage of a predetermined fixed value is determined and used to calculate the total charge of the insulating layer. The fixed value corresponds to either a flatband or midband condition.