Methods for Controlling Plasma Constituent Flux and Deposition During Semiconductor Fabrication and Apparatus for Implementing the Same

• US 20140034609A1
• Filed: 10/04/2013
• Published: 02/06/2014
• Est. Priority Date: 09/15/2010
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Dhindsa, Rajinder
• Granted Patent: US 9,267,208 B2
• Time in Patent Office: Days
• US Class Current: 216/59
• CPC Class Codes: C23F 1/08 Apparatus, e.g. for photomechanical printing surfaces photo- mechanical reproduction G03F
• CPC Class Codes: G05B 19/418 Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM]
• CPC Class Codes: G05B 2219/45031 Manufacturing semiconductor wafers
• CPC Class Codes: G05B 2219/45212 Etching, engraving, sculpturing, carving
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31144 using masks
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/67248 Temperature monitoring

Abstract

A time-dependent substrate temperature to be applied during a plasma process is determined. The time-dependent substrate temperature at any given time is determined based on control of a sticking coefficient of a plasma constituent at the given time. A time-dependent temperature differential between an upper plasma boundary and a substrate to be applied during the plasma process is also determined. The time-dependent temperature differential at any given time is determined based on control of a flux of the plasma constituent directed toward the substrate at the given time. The time-dependent substrate temperature and time-dependent temperature differential are stored in a digital format suitable for use by a temperature control device defined and connected to direct temperature control of the upper plasma boundary and the substrate. A system is also provided for implementing upper plasma boundary and substrate temperature control during the plasma process.

Claims

1. A method for defining a plasma process to be performed on a substrate, comprising:

determining a time-dependent substrate temperature to be applied during the plasma process, wherein the time-dependent substrate temperature at any given time is determined based on control of a sticking coefficient of a plasma constituent at the given time;

determining a time-dependent temperature differential between an upper plasma boundary and a substrate to be applied during the plasma process, wherein the substrate serves as a lower plasma boundary, and wherein the time-dependent temperature differential at any given time is determined based on control of a flux of the plasma constituent directed toward the substrate at the given time; and

storing the determined time-dependent substrate temperature and time-dependent temperature differential in a digital format suitable for use by a temperature control device defined and connected to direct temperature control of the upper plasma boundary and the substrate during the plasma process.

2. The method as recited in claim 1, wherein the sticking coefficient is a temperature dependent parameter that represents an affinity of the plasma constituent to adhere to the substrate.

3. The method as recited in claim 1, wherein an increase in substrate temperature corresponds to a reduced sticking coefficient representing a lower affinity of the plasma constituent to adhere to the substrate, and

wherein a decrease in substrate temperature corresponds to an increased sticking coefficient representing a higher affinity of the plasma constituent to adhere to the substrate.

4. The method as recited in claim 1, wherein the time-dependent temperature differential is defined based on a thermophoresis effect on the plasma constituent, whereby higher mass portions of the plasma constituent move toward lower temperature regions, and whereby lower mass portions of the plasma constituent move toward higher temperature regions, and wherein the movement of the plasma constituent based on its mass and regional temperatures to which it is exposed controls the flux of the plasma constituent directed toward the substrate.

5. The method as recited in claim 1, wherein the plasma process includes a high aspect ratio feature etching process in which a number of high aspect ratio features are etched into one or more materials present on the substrate.

6. The method as recited in claim 5, wherein the time-dependent temperature differential between the upper plasma boundary and the substrate is set during the high aspect ratio feature etching process to ensure that the flux of the plasma constituent toward the substrate provides sufficient amounts of appropriate masses of the plasma constituent near the substrate and within the number of high aspect ratio features.

7. The method as recited in claim 6, wherein the time-dependent substrate temperature is set during the high aspect ratio feature etching process to ensure that a sufficient amount of the plasma constituent adheres to a mask on the substrate so as to preserve the mask through completion of the plasma process, and to ensure that a sufficient amount of the plasma constituent adheres to sidewalls of the number of high aspect ratio features to protect the sidewalls from being adversely undercut, and to ensure that the number of high aspect ratio features remain open through completion of the plasma process.

8. The method as recited in claim 1, wherein the plasma constituent is a polymer that is resistant to etching capabilities of the plasma process.

9. The method as recited in claim 1, further comprising:

determining a time-dependent substrate support temperature necessary to achieve the determined time-dependent substrate temperature, wherein the substrate is held in thermal contact with the substrate support during the plasma process; and

storing the determined time-dependent substrate support temperature in a digital format suitable for use by a temperature control device defined and connected to direct temperature control of the substrate support during the plasma process.

10. The method as recited in claim 1, wherein each of the time-dependent substrate temperature and the time-dependent temperature differential between the upper plasma boundary and the substrate is defined as a function of radial position extending from a center of the substrate to a periphery of the substrate.

11. A system for plasma processing of a substrate, comprising:

a plasma processing chamber;

a substrate holder disposed within the plasma processing chamber and defined to hold a substrate, wherein the substrate holder includes one or more temperature control devices;

an upper electrode assembly disposed within the plasma processing chamber above and spaced apart from the substrate holder, wherein the upper electrode assembly includes one or more temperature control devices; and

a temperature control module defined to control the one or more temperature control devices of the substrate holder to maintain a target substrate temperature, the temperature control module further defined to control the one or more temperature control devices of the upper electrode assembly to maintain a target temperature differential between the substrate and the upper electrode assembly.

12. The system as recited in claim 11, wherein the target substrate temperature is a time-dependent substrate temperature to be applied during a plasma process.

13. The system as recited in claim 12, wherein the time-dependent substrate temperature at any given time is correlated to control of a sticking coefficient of a plasma constituent at the given time.

14. The system as recited in claim 11, wherein the target temperature differential between the substrate and the upper electrode assembly is a time-dependent temperature differential between the substrate and the upper electrode assembly to be applied during a plasma process.

15. The system as recited in claim 14, wherein the time-dependent temperature differential at any given time is correlated to control of a flux of a plasma constituent toward the substrate at the given time.

16. The system as recited in claim 11, further comprising:

a first temperature measurement device disposed to measure a temperature of the substrate holder, wherein the temperature of the substrate holder is correlated to the temperature of the substrate held thereon; and

a second temperature measurement device disposed to measure a temperature of the upper electrode assembly,

wherein each of the first and second temperature measurement devices is defined to convey respective temperature measurement signals to the temperature control module.

17. The system as recited in claim 11, wherein the one or more temperature control devices of the substrate holder includes a chiller and a heater embedded within the substrate holder.

18. The system as recited in claim 11, wherein the one or more temperature control devices of the upper electrode assembly includes a chiller and a heater embedded within the upper electrode assembly.

19. The system as recited in claim 11, wherein each of the substrate holder and the upper electrode assembly is defined to include multiple radially concentric temperature control zones with respective temperature control devices therein.