A memory includes an upper deck and a lower deck. The upper deck includes a first upper dummy word line. The lower deck includes a first lower dummy word line. A method for reducing program disturbance of the memory includes adjusting a first upper bias voltage applied to the first upper dummy word line and/or a first upper threshold voltage of the first upper dummy word line to adjust a first difference between the first upper bias voltage and the first upper threshold voltage; and adjusting a first lower bias voltage applied to the first lower dummy word line and/or a first lower threshold voltage of the first lower dummy word line to adjust a second difference between the first lower bias voltage and the first lower threshold voltage.