Dielectric spacer to prevent contacting shorting

A method comprising:

• forming an etching mask, wherein a portion of a first metal gate, gate spacers on opposite sides of the first metal gate, and an Inter-layer Dielectric (ILD) on a side of the gate spacers are revealed through the etching mask;
• performing a first etching process to form a first opening in the ILD, wherein exposed portions of the first metal gate, the gate spacers, and the ILD are removed;
• filling the first opening with a dielectric isolation region;
• performing a second etching process to form a second opening in the ILD, wherein a source/drain region on a side of the first metal gate is revealed through the second opening;
• depositing a dielectric layer, wherein the dielectric layer extends into the second opening;
• and
• removing a bottom portion of the dielectric layer at a bottom of the second opening, with remaining portions of the dielectric layer on sidewalls of the second opening forming a contact spacer, and the contact spacer has a sidewall contacting a sidewall of the dielectric isolation region.

A method comprising:

• forming a first gate stack;
• forming a dielectric isolation region, wherein the dielectric isolation region cuts the first gate stack into a first part and a second part;
• forming a contact plug;
• and
• forming a contact spacer, wherein the contact plug and the contact spacer extend into the dielectric isolation region, with a sidewall of the contact spacer contacting a sidewall of the dielectric isolation region, and the contact spacer encircles the contact plug, wherein the forming the contact spacer comprises:
• depositing a dielectric layer;
• and
• performing an etching process on the dielectric layer to remove horizontal portions of the dielectric layer, wherein vertical portions of the dielectric layer are left to form the contact spacer.