Method of manufacturing memory structure

A method of manufacturing a memory structure, comprising:

• forming a first dielectric layer on a source/drain region and a second dielectric layer on the first dielectric layer;
• forming a first opening in the second dielectric layer and the first dielectric layer by a first etching operation, wherein the first etching operation stops at a top surface of the source/drain region;
• extending the first opening into the source/drain region by a second etching operation to form a second opening, wherein the second opening comprises a first portion extending into the source/drain region, a second portion extending into the first dielectric layer, and a third portion extending into the second dielectric layer;
• and
• filling the second opening with a conductive material to form a contact for the source/drain region.

A method of manufacturing a memory structure, comprising:

• forming a first dielectric layer covering a first source/drain region and a second source/drain region;
• forming a second dielectric layer on the first dielectric layer;
• forming a first opening extending into the first source/drain region by a first etching operation and a second etching operation, wherein the first etching operation is selective to the first dielectric layer and the second dielectric layer, the second etching operation is selective to the first source/drain region, and sidewalls of the first opening are offset from sidewalls of the first source/drain region;
• forming a second opening extending into the second source/drain region by a third etching operation and a fourth etching operation, wherein the third etching operation is selective to the first dielectric layer and the second dielectric layer, and the fourth etching operation is selective to the second source/drain region;
• and
• filling the first opening and the second opening with a conductive material to form a first contact and a second contact, respectively.