Method of making a self-aligned contact in semiconductor device

Claim 1

A method of making a self-aligned contact in a semiconductor device comprising the steps of: a) forming sequentially a first dielectric layer, a second conductive line, and a second dielectric layer on a semiconductor substrate; b) forming a contact hole by successively removing the second dielectric layer, the second conductive line and the first dielectric layer from above a region of the semiconductor substrate, thereby exposing the semiconductor substrate, said contact hole thereby having an inner wall surface that includes a sidewall of the second conductive line and a sidewall of the second dielectric layer; c) forming a first conductive line by depositing impurities into the exposed semiconductor substrate; d) forming an oxide layer at the side wail of the second conductive line within said contact hole and on the first conductive line; e) forming a nitride layer on the surface of the oxide layer and the second dielectric layer, the nitride layer thereby having a nitride wall portion within said contact hole, said nitride wall portion On the oxide layer at the sidewall of the second conductive line and on the sidewall of the second dielectric layer; f) forming a silicon spacer on the nitride wall portion; g) forming a thermal oxide by thermally oxidizing said silicon spacer to a desired thickness; h) exposing the first conductive line by removing said nitride layer, oxide layer, and a portion of the thermal oxide layer which are exposed to the inside of the contact hole, and also by removing said nitride layer and the second dielectric layer outside of the contact hole an appropriate thickness, while leaving a substantial thickness of the second dielectric layer and of the thermal oxide formed on the surface of the silicon spacer; and i) forming a third conductive line contacted with the exposed first conductive line.

Claim 2

A method of making a self-aligned contact in a semiconductor device comprising the steps of: a) forming sequentially a first dielectric layer, a second conductive line, and a second dielectric layer on a semiconductor substrate; b) forming a contact hole by successively removing the second dielectric layer, the second conductive line and the first dielectric layer from above a region of the semiconductor substrate, thereby exposing the semiconductor substrate, said contact hole thereby having an inner wall surface that includes a sidewall of the second conductive line and a sidewall of the second dielectric layer; c) forming a first conductive line by depositing impurities into the exposed semiconductor substrate; d) forming an oxide layer at the side wail of the second conductive line within said contact hole and on the first conductive line; e) forming a nitride layer on the surface of the oxide layer and the second dielectric layer, the nitride layer thereby having a nitride wall portion within said contact hole, said nitride wall portion On the oxide layer at the sidewall of the second conductive line and on the sidewall of the second dielectric layer; f) forming a silicon spacer on the nitride wall portion; g) forming a thermal oxide by thermally oxidizing said silicon spacer to a desired thickness; h) exposing the first conductive line by removing said nitride layer, oxide layer, and a portion of the thermal oxide layer which are exposed to the inside of the contact hole, and also by removing said nitride layer and the second dielectric layer outside of the contact hole an appropriate thickness, while leaving a substantial thickness of the second dielectric layer and of the thermal oxide formed on the surface of the silicon spacer; and i) forming a third conductive line contacted with the exposed first conductive line.