Patent ID: 7951706

Claim:
A method of manufacturing a semiconductor device, comprising: forming a first metal layer on a lower structural layer; forming an interlayer metal dielectric (IMD) layer on the first metal layer, wherein a first height difference is formed in the first metal layer during forming the IMD layer, and wherein a second height difference corresponding to the first height difference is formed in the IMD layer; forming a sacrificial oxide layer having a third height difference corresponding to the second height difference on the IMD layer, wherein a height of the sacrificial oxide layer is greater than that of the height difference in the IMD layer, and wherein a height of the third height difference is less than that of the first height difference and that of the second height difference; and planarizing the sacrificial oxide layer and a portion of the IMD layer to substantially eliminate the second height difference in the IMD layer and provide a substantially flat IMD layer.