System and method for mitigating oxide growth in a gate dielectric

Patent metadata

Field	Value
Publication number	US-9368355-B2
Application number	US-201514858227-A
Country	US
Kind code	B2
Filing date	Sep 18, 2015
Priority date	May 13, 2003
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

Oxide growth of a gate dielectric layer that occurs between processes used in the fabrication of a gate dielectric structure can be reduced. The reduction in oxide growth can be achieved by maintaining the gate dielectric layer in an ambient effective to mitigate oxide growth of the gate dielectric layer between at least two sequential process steps used in the fabrication the gate dielectric structure. Maintaining the gate dielectric layer in an ambient effective to mitigate oxide growth also improves the uniformity of nitrogen implanted in the gate dielectric.

First claim

What is claimed is:

1. A method for forming a device structure on a substrate, comprising:
forming a dielectric layer on the substrate in a first process chamber of a processing system, the first process chamber having a first pumping element configured to evacuate gas from the first process chamber;
introducing nitrogen atoms in the dielectric layer using a plasma process in a second process chamber of the processing system, the second process chamber having a second pumping element configured to evacuate gas from the second process chamber;
performing a thermal process in a third process chamber;
transferring the substrate between the first process chamber, the second process chamber, and the third process chamber through a transfer chamber of the processing system, wherein the transfer chamber is connected to the first process chamber via a first vacuum lock door and connected the second process chamber via a second vacuum lock door, the transfer chamber having a gas distribution system and a third, distinct pumping element that provide an ambient of uniform, laminar inert gas flow within the transfer chamber during transfer of the substrate between the first process chamber, the second process chamber, and the third process chamber; and
introducing the substrate to the processing system through a load lock distinct from said transfer chamber to allow introduction and removal of the substrate from the processing system.

2. The method of claim 1 , wherein the nitrogen atoms are introduced into a top surface of the dielectric layer by flowing N 2 in the plasma process having a power of 2 W to 3000 W and a pressure of 5 mTorr to 50 T.

3. The method of claim 1 , wherein forming the dielectric layer comprises performing an in-situ steam generation (ISSG) process at a pressure of 1 Torr to 20 Torr.

4. The method of claim 3 , wherein a temperature of the first process chamber is maintained at temperature of 500° C. to 700° C. prior to formation of the dielectric layer and 850° to 1050° C. during the formation of the dielectric layer.

5. The method of claim 1 , wherein during the transferring, the gas distribution system and the third pumping element maintain a pressure of 3 Torr to 20 Torr in the transfer chamber and actively purge the transfer chamber using N2 flowed at a rate of 2 liters per minute to 7 liters per minute.

6. The method of claim 1 , wherein the step of performing the thermal process uses O 2 and a temperature of 400° C. to 1200° C.

7. The method of claim 1 , wherein the step of performing the thermal process uses NO and a temperature of 400° C. to 1200° C.

8. The method of claim 1 , further comprising forming a polysilicon layer over the dielectric layer in a fourth process chamber connected to the transfer chamber, wherein the substrate is transferred through the transfer chamber to the fourth process chamber under an ambient of uniform, laminar inert gas flow within the transfer chamber.

9. The method of claim 1 , wherein the first pumping element provides a pressure of 1 Torr to 20 Torr in the first process chamber during the step of forming the dielectric layer, the second pumping element provides a pressure of 5 mTorr to 50 Torr in the second process chamber during the step of introducing the nitrogen atoms, the third pumping element provides a pressure of 3 Torr to 200 Torr in the transfer chamber during the transferring step, and a fourth pumping element provides a pressure of 0.5 Torr to 50 Torr in the third processing chamber during the step of performing the thermal process.

10. A method for forming at least part of a gate dielectric structure on a substrate, comprising:
forming a gate dielectric layer over the substrate in a first process chamber of a processing system using an in-situ steam generation (ISSG) process, the first process chamber having a first pumping element, the first pumping element providing a pressure in the range of 1 to 20 Torr in the first process chamber while forming the gate dielectric layer, wherein a temperature of the first process chamber is 850° to 1050° C. during the formation of the gate dielectric layer;
introducing nitrogen atoms in a top surface of the gate dielectric layer in a second process chamber of the processing system using plasma nitridation with N 2 and a power of 2 watts to 3000 watts, the second process chamber having a second pumping element, the second pumping element providing a pressure of 5 mTorr to 50 Torr in the second process chamber while introducing the nitrogen atoms;
performing a thermal process in a third process chamber at a temperature in the range of 400° C. to 1200° C.;
transferring the substrate between the first process chamber, the second process chamber, and the third process chamber through a transfer chamber of the processing system, wherein the transfer chamber is connected to the first process chamber via a first vacuum lock door and connected the second process chamber via a second vacuum lock door, the transfer chamber having a gas distribution system and a third, distinct pumping element, wherein the gas distribution system and the third pumping element maintain a pressure of about 3 Torr to about 20 Torr in the transfer chamber and actively purge the transfer chamber by flowing N 2 at a rate of 2 liters per minute to 7 liters per minute during the transferring; and
introducing the substrate to the processing system through a load lock distinct from said transfer chamber to allow introduction and removal of the substrate from the processing system.

11. The method of claim 10 , wherein the thermal process is performed at a temperature of about 900° C. to about 1050° C.

12. The method of claim 11 , wherein the thermal process is performed with O 2 , N 2 O, or NO.

13. The method of claim 10 , further comprising the steps of:
transferring the substrate through the transfer chamber to a fourth process chamber, while the gas distribution system and the third pumping element maintain a pressure of about 3 Torr to 20 Torr in the transfer chamber and actively purge the transfer chamber by flowing N 2 flowed at a rate of 2 liters per minute to 7 liters per minute; and
depositing a polysilicon layer over the gate dielectric layer in the fourth process chamber.

14. The method of claim 10 , wherein the step of introducing nitrogen atoms uses N 2 and He.

15. The method of claim 10 , wherein the step of transferring the substrate between the first process chamber, the second process chamber, and the third process chamber through a transfer chamber of the processing system, comprises:
transferring the substrate from the first process chamber through the transfer chamber to the second process chamber while the gas distribution system and the third pumping element maintain a pressure of about 3 Torr to about 20 Torr in the transfer chamber and actively purge the transfer chamber by flowing N 2 flowed at a rate of 2 liters per minute to 7 liters per minute; and
transferring the substrate from the second process chamber through the transfer chamber to the third process chamber while the gas distribution system and the third pumping element maintain a pressure of about 3 Torr to about 20 Torr in the transfer chamber and actively purge the transfer chamber by flowing N 2 flowed at a rate of 2 liters per minute to 7 liters per minute.

16. The method of claim 15 , wherein the step of transferring the substrate from the first process chamber through the transfer chamber to the second process chamber further comprises cooling the substrate.

17. A method for forming device structure on a substra

Assignees

• Texas Instruments Inc

Inventors

• Bevan Malcolm J
• Bu Haowen
• Niimi Hiroaki
• Alshareef Husam N

Classifications

• H10P14/69392

  the material containing hafnium, e.g. HfO2 · CPC title

• H10P14/6339

  deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD · CPC title

• H10P14/6322

  Formation by thermal treatments (formation by plasma treatment H10P14/6319) · CPC title

• H10P14/6319

  Formation by plasma treatments, e.g. plasma oxidation of the substrate · CPC title

• H10P95/90

  Thermal treatments, e.g. annealing or sintering · CPC title