Method for planarizing a shallow trench isolation

Claim 1

A method of planarizing an isolation region; comprising the steps of: a) forming a pad oxide layer, a first nitride layer, a sacrificial oxide layer and a second nitride layer over a substrate; b) forming a trench through said pad oxide layer, said first nitride layer, said sacrificial oxide layer and said second nitride layer and in said substrate; c) depositing an oxide layer filling said trench and over said second nitride layer; d) chemical-mechanical polishing said oxide layer and said second nitride layer down to a level so that said second nitride layer has a thickness of between about 50 and 200 Å; e) removing said second nitride layer and said sacrificial oxide layer and a thickness of said oxide layer; f) chemical-mechanical polishing said oxide layer and said first nitride layer so that the top surface of said oxide layer is about level within 10 percent, with the top surface of said first nitride layer.

Claim 2

A method of planarizing an isolation region; comprising the steps of: a) forming a pad oxide layer, a first nitride layer, a sacrificial oxide layer and a second nitride layer over a substrate; b) forming a trench through said pad oxide layer, said first nitride layer, said sacrificial oxide layer and said second nitride layer and in said substrate; c) depositing an oxide layer filling said trench and over said second nitride layer; d) chemical-mechanical polishing said oxide layer and said second nitride layer down to a level so that said second nitride layer has a thickness of between about 50 and 200 Å; e) removing said second nitride layer and said sacrificial oxide layer and a thickness of said oxide layer; f) chemical-mechanical polishing said oxide layer and said first nitride layer so that the top surface of said oxide layer is about level within 10 percent, with the top surface of said first nitride layer.

Claim 11

A method of planarizing an isolation region; comprising the steps of: a) forming a pad oxide layer, a first nitride layer, a sacrificial oxide layer and a second nitride layer over a substrate; (1) said pad oxide layer has a thickness of between about 40 and 80 Å; (2) said first nitride layer has a thickness of between about 600 and 1000 Å; (3) said sacrificial oxide layer has a thickness of between about 100 and 200 Å; (4) said second nitride layer has a thickness of between about 200 and 1500 Å; b) forming a trench through said pad oxide layer, said first nitride layer, said sacrificial oxide layer and said second nitride layer and in said substrate; (1) said trench has a depth in said substrate between 2500 and 3000 Å; c) depositing an oxide layer filling said trench and over said second nitride layer; (1) said oxide layer formed by a high density plasma chemical vapor deposition process deposition; (2) said oxide layer having a thickness in said trench of between about 4500 and 5000 Å; (3) said oxide layer having a thickness over said second nitride layer between 1500 and 2500 Å; d) chemical-mechanical polishing said oxide layer and said second nitride layer down to a level so that said second nitride layer has a thickness of between about 50 and 200 Å; e) removing said second nitride layer and said sacrificial oxide layer and a thickness of said oxide layer; and f) chemical-mechanical polishing said oxide layer and said first nitride layer so that said oxide layer is level with said first nitride layer.

Claim 12

A method of planarizing an isolation region; comprising the steps of: a) forming a pad oxide layer, a first nitride layer, a sacrificial oxide layer and a second nitride layer over a substrate; (1) said pad oxide layer has a thickness of between about 40 and 80 Å; (2) said first nitride layer has a thickness of between about 600 and 1000 Å; (3) said sacrificial oxide layer has a thickness of between about 100 and 200 Å; (4) said second nitride layer has a thickness of between about 200 and 1500 Å; b) forming a trench through said pad oxide layer, said first nitride layer, said sacrificial oxide layer and said second nitride layer and in said substrate; (1) said trench has a depth in said substrate between 2500 and 3000 Å; c) depositing an oxide layer filling said trench and over said second nitride layer; (1) said oxide layer formed by a high density plasma chemical vapor deposition process deposition; (2) said oxide layer having a thickness in said trench of between about 4500 and 5000 Å; (3) said oxide layer having a thickness over said second nitride layer between 1500 and 2500 Å; d) chemical-mechanical polishing said oxide layer and said second nitride layer down to a level so that said second nitride layer has a thickness of between about 50 and 200 Å; e) removing said second nitride layer and said sacrificial oxide layer and a thickness of said oxide layer; and f) chemical-mechanical polishing said oxide layer and said first nitride layer so that said oxide layer is level with said first nitride layer.

Claim 13

A method of planarizing an isolation region; comprising the steps of: a) forming a pad oxide layer, a first nitride layer, a sacrificial oxide layer and a second nitride layer over a substrate; b) forming a trench through said pad oxide layer, said first nitride layer, said sacrificial oxide layer and said second nitride layer and in said substrate; c) depositing an oxide layer filling said trench and over said second nitride layer; d) chemical-mechanical polishing said oxide layer and said second nitride layer down to a level; removing said second nitride layer and said sacrificial oxide layer and a portion of said oxide layer; and e) chemical-mechanical polishing said oxide layer and said first nitride layer so that the top surface of said oxide layer is about level with the top surface of said first nitride layer within 20 percent of the thickness of said first nitride layer.

Claim 14

A method of planarizing an isolation region; comprising the steps of: a) forming a pad oxide layer, a first nitride layer, a sacrificial oxide layer and a second nitride layer over a substrate; b) forming a trench through said pad oxide layer, said first nitride layer, said sacrificial oxide layer and said second nitride layer and in said substrate; c) depositing an oxide layer filling said trench and over said second nitride layer; d) chemical-mechanical polishing said oxide layer and said second nitride layer down to a level; removing said second nitride layer and said sacrificial oxide layer and a portion of said oxide layer; and e) chemical-mechanical polishing said oxide layer and said first nitride layer so that the top surface of said oxide layer is about level with the top surface of said first nitride layer within 20 percent of the thickness of said first nitride layer.