Plasma processing chamber with dual axial gas injection and exhaust

• US 8,869,742 B2
• Filed: 08/04/2010
• Issued: 10/28/2014
• Est. Priority Date: 08/04/2010
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Dhindsa, Rajinder, Marakhatnov, Alexei, Bailey, Andrew D. III
• Primary Examiner(s): Zervigon, Rudy
• Application Number:
  US12/850,552
• Publication Number:
  US 20120034786A1
• Time in Patent Office: 1,546 Days
• Field of Search: 118/723.E, 118/723.R, 118/728, 156/345.43, 156/345.44, 156/345.45, 156/345.51
• US Class Current: 118/723.E
• CPC Class Codes: C23C 16/4412 Details relating to the exhausts, e.g. pumps, filters, scrubbers, particle traps
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/45574 Nozzles for more than one gas
• CPC Class Codes: C23C 16/45576 Coaxial inlets for each gas
• CPC Class Codes: C23C 16/50 using electric discharges generation and control of plasma in discharge tubes for surface treatment H01J37/32, H01J37/34
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow
• CPC Class Codes: H01J 37/32834 Exhausting
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/31 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques encapsulating layers H01L21/56; After treatment of these layers; Selection of materials for these layers

Abstract

An electrode is exposed to a plasma generation volume and is defined to transmit radiofrequency power to the plasma generation volume, and includes an upper surface for holding a substrate in exposure to the plasma generation volume. A gas distribution unit is disposed above the plasma generation volume and in a substantially parallel orientation to the electrode. The gas distribution unit includes an arrangement of gas supply ports for directing an input flow of a plasma process gas into the plasma generation volume in a direction substantially perpendicular to the upper surface of the electrode. The gas distribution unit also includes an arrangement of through-holes that each extend through the gas distribution unit to fluidly connect the plasma generation volume to an exhaust region. Each of the through-holes directs an exhaust flow from the plasma generation volume in a direction substantially perpendicular to the upper surface of the electrode.

Claims

1. A semiconductor wafer processing apparatus, comprising:

a chuck including an electrode exposed to a plasma generation volume, the electrode defined to transmit radiofrequency (RF) power to the plasma generation volume, the electrode having an upper surface defined to hold a substrate in exposure to the plasma generation volume, the chuck having a top surface that circumscribes a perimeter of a top surface of the electrode; and

a gas distribution unit disposed above the plasma generation volume and in a substantially parallel orientation with respect to the electrode, the gas distribution unit defined to include an arrangement of gas supply ports defined to direct an input flow of a plasma process gas into the plasma generation volume in a direction substantially perpendicular to the upper surface of the electrode, the gas distribution unit further defined to include an arrangement of through-holes that each extend through the gas distribution unit to fluidly connect the plasma generation volume to an exhaust region, wherein each of the through-holes is defined to direct an exhaust flow of the plasma process gas from the plasma generation volume in a direction substantially perpendicular to the upper surface of the electrode, and

wherein the gas distribution unit is defined as a plate formed to separate the plasma generation volume from the exhaust region, and wherein each gas supply port in the arrangement of gas supply ports is defined at a lower surface of the plate to provide for distribution of plasma process gas to the plasma generation volume;

an outer peripheral structure having a top surface and a bottom surface and formed to extend in a solid form between its top and bottom surfaces, the bottom surface of the outer peripheral structure disposed on the top surface of the chuck, the gas distribution unit disposed on the top surface of the outer peripheral structure, the outer peripheral structure defined to surround and enclose a perimeter of the plasma generation volume such that an uninterrupted fluid seal is present between the bottom surface of the outer peripheral structure and the top surface of the chuck around the perimeter of the plasma generation volume, and such that an uninterrupted fluid seal is present between the top surface of the outer peripheral structure and the gas distribution unit around the perimeter of the plasma generation volume.

2. The semiconductor wafer processing apparatus as recited in claim 1, wherein the electrode forms a lower surface of the plasma generation volume, and wherein a lower surface of the plate provides an upper boundary of the plasma generation volume.

3. The semiconductor wafer processing apparatus as recited in claim 1, wherein the gas distribution unit is formed of an electrically conductive material and is electrically connected to a reference ground potential such that the gas distribution unit provides a ground electrode for the plasma generation volume.

4. The semiconductor wafer processing apparatus as recited in claim 1, wherein the electrode is movable in a direction toward and away from the gas distribution unit to provide for control of a distance extending across the plasma generation volume perpendicular to both the electrode and gas distribution unit.

5. The semiconductor wafer processing apparatus as recited in claim 1, further comprising:

an exhaust manifold disposed above the gas distribution unit to form the exhaust region;

a valve fluidly connected to the exhaust manifold; and

a pump fluidly connected to the valve to provide a suction force to the valve, wherein the valve is operable to control an exhaust flow from the plasma generation volume through the gas distribution unit.

6. The semiconductor wafer processing apparatus as recited in claim 1, further comprising:

a chamber defined to enclose the electrode and the gas distribution unit within an interior cavity of the chamber, wherein the interior cavity of the chamber forms the exhaust region;

a pump fluidly connected to the interior cavity of the chamber to provide a suction force to the interior cavity of the chamber; and

a valve disposed to control a fluid flow from the interior cavity of the chamber due to the suction force provided by the pump.

11. The semiconductor wafer processing apparatus as recited in claim 1, further comprising:

a flow control plate disposed on an upper surface of the gas distribution unit, the flow control plate defined to control which of the through-holes are exposed to direct the exhaust flow of the plasma process gas from the plasma generation volume and which of the through-holes are closed at a given time.

12. The semiconductor wafer processing apparatus as recited in claim 11, wherein the flow control plate is a disc having multiple patterns of holes defined through the disc, such that each of the multiple patterns of holes aligns with a different set of the through-holes at a corresponding rotational position of the disc relative to the upper surface of the gas distribution unit.

13. The semiconductor wafer processing apparatus as recited in claim 12, wherein each of the multiple patterns of holes is defined to expose a different number or a different spatial pattern of the through-holes within the gas distribution unit.

17. The semiconductor wafer processing apparatus as recited in claim 1, wherein each through-hole of the arrangement of through-holes is defined at the lower surface of the plate such that each through-hole is spaced apart from neighboring gas supply ports by some portion of the lower surface of the plate.

21. The semiconductor wafer processing apparatus as recited in claim 1, wherein the gas distribution unit includes interior gas supply channels fluidly connected to the arrangement of gas supply ports, the interior gas supply channels defined to fluidly separate the arrangement of gas supply ports into multiple gas supply regions including a center gas supply region and one or more annular gas supply regions defined concentrically about the center gas supply region across the gas distribution unit such that each of the one or more annular gas supply regions circumscribes the center gas supply region, wherein each gas supply port of a given one of the multiple gas supply regions is plumbed to a same gas flow control device, and wherein gas supply ports of different ones of the multiple gas supply regions are plumbed to different gas flow control devices to provide for independent control of gas flow to the multiple gas supply regions.

7. A system for semiconductor wafer processing, comprising:

a chamber defined to have an interior cavity;

a chuck disposed within the interior cavity of the chamber, the chuck having an upper surface defined to hold a substrate in exposure to a plasma generation volume, the chuck defined to supply radiofrequency (RF) power to the plasma generation volume;

an outer peripheral structure disposed on the chuck and defined to surround and enclose a perimeter of the plasma generation volume such that an uninterrupted fluid seal is present between the outer peripheral structure and the chuck around the perimeter of the plasma generation volume;

a gas distribution unit disposed on the outer peripheral structure such that an uninterrupted fluid seal is present between the outer peripheral structure and the gas distribution unit around the perimeter of the plasma generation volume, the gas distribution unit defined to extend across the plasma generation volume in a substantially parallel relationship to the upper surface of the chuck, the gas distribution unit defined to include an arrangement of gas supply ports defined to direct an input flow of a plasma process gas into the plasma generation volume, the gas distribution unit further defined to include an arrangement of through-holes;

an exhaust region defined within the chamber above the gas distribution unit such that each of the through-holes extends through the gas distribution unit to fluidly connect the plasma generation volume to the exhaust region, wherein the arrangement of through-holes is an only means for exhausting gases from the plasma generation volume; and

a pump fluidly connected to the exhaust region to remove gases from the exhaust region.

8. The system for semiconductor wafer processing as recited in claim 7, wherein each of the gas supply ports is defined to direct the input flow of the plasma process gas into the plasma generation volume in a direction substantially perpendicular to the upper surface of the chuck, and

wherein each of the through-holes is defined to direct the exhaust flow of the plasma process gas from the plasma generation volume in a direction substantially perpendicular to the upper surface of the chuck.

9. The system for semiconductor wafer processing as recited in claim 7, wherein the gas distribution unit is formed of an electrically conductive material and is electrically connected to a reference ground potential such that the gas distribution unit provides a ground electrode for the plasma generation volume.

10. The system for semiconductor wafer processing as recited in claim 7, wherein the chuck is movable in a direction toward and away from the gas distribution unit to provide for control of a distance extending across the plasma generation volume perpendicular to both the upper surface of the chuck and the gas distribution unit.

14. The system for semiconductor wafer processing as recited in claim 7, further comprising:

a flow control plate disposed on an upper surface of the gas distribution unit, the flow control plate defined to control which of the through-holes are exposed to fluidly connect the plasma generation volume to the exhaust region and which of the through-holes are closed at a given time.

15. The system for semiconductor wafer processing as recited in claim 14, wherein the flow control plate is a disc having multiple patterns of holes defined through the disc, such that each of the multiple patterns of holes aligns with a different set of the through-holes at a corresponding rotational position of the disc relative to the upper surface of the gas distribution unit.

16. The system for semiconductor wafer processing as recited in claim 15, wherein each of the multiple patterns of holes is defined to expose a different number or a different spatial pattern of the through-holes within the gas distribution unit.

18. The system for semiconductor wafer processing as recited in claim 7, wherein the gas distribution unit is defined as a plate formed to separate the plasma generation volume from the exhaust region, and wherein each gas supply port in the arrangement of gas supply ports is defined at a lower surface of the plate with a diffuser shape to provide for distribution of plasma process gas to the plasma generation volume.

19. The system for semiconductor wafer processing as recited in claim 18, wherein each through-hole of the arrangement of through-holes is defined at the lower surface of the plate such that each through-hole is spaced apart from neighboring gas supply ports by some portion of the lower surface of the plate.

20. The system for semiconductor wafer processing as recited in claim 7, wherein the gas distribution unit includes interior gas supply channels fluidly connected to the arrangement of gas supply ports, the interior gas supply channels defined to fluidly separate the arrangement of gas supply ports into multiple gas supply regions including a center gas supply region and one or more annular gas supply regions defined concentrically about the center gas supply region across the gas distribution unit such that each of the one or more annular gas supply regions circumscribes the center gas supply region,

the system including a number of gas flow control devices corresponding to a number of the multiple gas supply regions into which the arrangement of gas supply ports is separated, wherein each gas supply port of a given one of the multiple gas supply regions is plumbed to a same gas flow control device, and wherein gas supply ports of different ones of the multiple gas supply regions are plumbed to different gas flow control devices to provide for independent control of gas flow to the multiple gas supply regions.