Method For Controlling In-Plane Uniformity Of Substrate Processed By Plasma-Assisted Process

• US 20140367359A1
• Filed: 06/12/2013
• Published: 12/18/2014
• Est. Priority Date: 06/12/2013
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Nakano, Ryu, Inoue, Naoki
• Granted Patent: US 9,123,510 B2
• Time in Patent Office: Days
• US Class Current: 216/67
• CPC Class Codes: C23C 16/4551 Jet streams
• CPC Class Codes: C23C 16/45519 Inert gas curtains
• CPC Class Codes: C23C 16/45536 Use of plasma, radiation or electromagnetic fields
• CPC Class Codes: C23C 16/4585 Devices at or outside the perimeter of the substrate support, e.g. clamping rings, shrouds
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: H01J 37/32431 Constructional details of the reactor
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow

Abstract

A method for controlling in-plane uniformity of a substrate processed by plasma-assisted process in a reactor, includes: supplying a principal gas to a reaction space, and discharging radially the principal gas from the reaction space through an annular duct; and supplying an secondary gas to the reaction space from an area in close proximity to an outer periphery of a susceptor, outside an outer circumference of the substrate as viewed from above, so as to flow at least partially in an inward direction passing the outer circumference of the substrate, reversing the direction of the secondary gas to flow toward the annular duct in a vicinity of the outer circumference of the substrate, and discharging radially the secondary gas together with the principal gas from the reaction space through the annular duct.

Claims

1. A method for controlling in-plane uniformity of a substrate processed by plasma-assisted process in a reactor comprising:

a susceptor and a showerhead disposed in parallel facing each other and conductively coupled for plasma discharge in a reaction space formed between the susceptor and the showerhead; and

an annular duct circularly surrounding the susceptor, said method comprising;

supplying a principal gas for plasma-assisted process of a substrate placed on the susceptor, to the reaction space through the showerhead, and discharging radially the principal gas from the reaction space through the annular duct; and

while supplying the principal gas to the reaction space, supplying a secondary gas to the reaction space from an area in close proximity to an outer periphery of the susceptor, outside an outer circumference of the substrate as viewed from above, so as to flow at least partially in an inward direction passing the outer circumference of the substrate, reversing the direction of the secondary gas to flow toward the annular duct in a vicinity of the outer circumference of the substrate, and discharging radially the secondary gas together with the principal gas from the reaction space through the annular duct.

2. The method according to claim 1, wherein the reactor comprises a reaction chamber and a transfer chamber under the reaction chamber, wherein the reaction chamber and the transfer chamber are separated by a separation ring having an opening in which the susceptor is disposed and a top surface of the susceptor is approximately flush with the separation ring during the plasma-assisted process, wherein the secondary gas is supplied to the reaction space through a clearance between the separation ring and the susceptor at a flow rate such that the secondary gas enters the reaction space partially in the inward direction passing the outer circumference of the substrate, reverses direction to flow toward the annular duct in a vicinity of the outer circumference of the substrate, and is discharged radially together with the principal gas from the reaction space through the annular duct.

3. The method according to claim 1, wherein the reactor further comprises multiple inflow ports exposed to the reaction space near an opening of the annular duct along the annular duct, wherein the secondary gas is supplied to the reaction space through the multiple inflow ports in the inward direction passing the outer circumference of the substrate at a flow rate such that the secondary gas enters the reaction space, reverses direction to flow toward the annular duct in a vicinity of the outer circumference of the substrate, and is discharged radially together with the principal gas from the reaction space through the opening of the annular duct.

4. The method according to claim 3, wherein the inflow ports are multiple not only on a horizontal plane along the annular duct but also along a vertical direction.

5. The method according to claim 2, wherein the clearance between the separation ring and the susceptor varies along the outer periphery of the susceptor to change the flow rate of the secondary gas along the outer periphery of the susceptor.

6. The method according to claim 5, wherein a center of the separation ring is shifted from a center of the susceptor toward a gate valve disposed in a side wall of the transfer chamber, through which gate valve the substrate is taken into and out of the transfer chamber.

7. The method according to claim 3, wherein the multiple inflow ports are allocated unevenly along the annular duct to change the flow rate of the secondary gas along the outer periphery of the susceptor.

8. The method according to claim 4, wherein the multiple inflow ports are allocated unevenly along the annular duct to change the flow rate of the secondary gas along the outer periphery of the susceptor.

9. The method according to claim 2, wherein the clearance between the separation ring and the susceptor is no less than 0.5 mm but less than 10 mm.

10. The method according to claim 5, wherein the clearance between the separation ring and the susceptor varies in a range of about 0.5 mm to about 10 mm.

11. The method according to claim 1, wherein the secondary gas is an inert gas or an oxidizing gas.

12. The method according to claim 9, wherein the secondary gas is supplied at a flow rate of about 500 sccm or higher.

13. The method according to claim 1, wherein the plasma-assisted process is plasma-enhanced atomic layer deposition (PEALD) or plasma-enhanced chemical vapor deposition (PECVD).

14. The method according to claim 1, wherein the plasma-assisted process is plasma-assisted etching or ashing.

15. The method according to claim 1, wherein the in-plane uniformity of the substrate is such that in-plane uniformity of thickness of a processed film of the substrate is about 2%.

16-20. -20. (canceled)