Patent ID: 11923453
Assignee: CSMC TECHNOLOGIES FAB2 CO., LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for preparing a lateral double-diffused metal oxide semiconductor field-effect transistor (LDMOS) device, comprising:
providing a semiconductor substrate, a body region and a drift region being formed in the semiconductor substrate, a source region being provided in the body region, a drain region being provided in the drift region, and a gate structure being further formed on the semiconductor substrate;
depositing a first oxide layer on the semiconductor substrate, the first oxide layer being located on the drain region and on a part of the drift region;
forming a barrier layer on the semiconductor substrate, the barrier layer comprising n−1 etch stop layers, n being an integer greater than or equal to 2;
wherein when n is greater than 2, the etch stop layers are provided in a stacked manner, and an insulating layer is provided between adjacent etch stop layers; the barrier layer covers both directly on the drift region and directly on the first oxide layer, the barrier layer has a step, and a plane of the barrier layer directly covered on the drift region is lower than a plane of the barrier layer directly covered on the first oxide layer; and
forming an interlayer dielectric layer and etching the interlayer dielectric layer and the barrier layer to form n levels of field plate holes;
wherein a first level field plate hole to an (n−1)-th level field plate hole are provided in the interlayer dielectric layer and are stopped at a first etch stop layer to an (n−1)-th etch stop layer corresponding to the barrier layer directly covered on the drift region respectively, and an n-th level field plate hole is further provided in the interlayer dielectric layer and is stopped at the (n−1)-th etch stop layer corresponding to the barrier layer directly covered on the first oxide layer.