Plasma Processing Chamber with Dual Axial Gas Injection and Exhaust

• US 20120034786A1
• Filed: 08/04/2010
• Published: 02/09/2012
• Est. Priority Date: 08/04/2010
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Dhindsa, Rajinder, Bailey, Andrew D. III, Marakhatnov, Alexei
• Granted Patent: US 8,869,742 B2
• Time in Patent Office: Days
• US Class Current: 438/710
• 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:

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; 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.

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 the gas distribution unit is defined as a plate formed to separate the plasma generation volume from the exhaust region, such that 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 2, wherein the plate includes interior gas supply channels fluidly connected to the arrangement of gas supply ports defined on the lower surface of the plate to distribute the plasma process gas to the plasma generation volume.

4. The semiconductor wafer processing apparatus as recited in claim 3, wherein the gas supply channels are defined to fluidly separate the arrangement of gas supply ports into multiple concentric regions across the lower surface of the plate, such that flow rates of the plasma process gas to the gas supply ports within each of the multiple concentric regions is independently controlled.

5. 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.

6. 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.

7. 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.

8. 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.

9. 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;

a gas distribution unit disposed on the outer peripheral structure and 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; and

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

10. The system for semiconductor wafer processing as recited in claim 9, 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.

11. The system for semiconductor wafer processing as recited in claim 9, 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.

12. The system for semiconductor wafer processing as recited in claim 9, 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.

13. A method for semiconductor wafer processing, comprising:

holding a semiconductor wafer in a substantially parallel orientation to a gas distribution unit such that a plasma processing volume is formed between the semiconductor wafer and the gas distribution unit;

flowing a plasma processing gas from within the gas distribution unit into the plasma processing volume in a direction substantially perpendicular to the semiconductor wafer; and

directing an exhaust flow of plasma processing gas from within the plasma processing volume through the gas distribution unit in a direction substantially perpendicular to the semiconductor wafer, whereby the exhaust flow of plasma processing gas through the gas distribution unit is the only exhaust flow of plasma processing gas from within the plasma processing volume.

14. The method as recited in claim 13, wherein the gas distribution unit is defined as a plate that extends over an entirety of the plasma processing volume.

15. The method as recited in claim 13, further comprising:

transmitting radiofrequency (RF) power to the plasma processing volume to transform the plasma processing gas into a plasma in exposure to the semiconductor wafer.

16. The method as recited in claim 15, wherein the semiconductor wafer is held on an upper surface of a chuck, and wherein the chuck is operated as an electrode to transmit the RF power to the plasma processing volume.

17. The method as recited in claim 13, wherein flowing the plasma processing gas from within the gas distribution unit into the plasma processing volume and directing the exhaust flow of plasma processing gas from within the plasma processing volume through the gas distribution unit are performed in a pulsed manner to control a residence time of plasma in exposure to the semiconductor wafer.

18. The method as recited in claim 13, wherein the plasma processing gas is flowed from multiple independently controllable gas supply zones within the gas distribution unit into the plasma processing volume.

19. The method as recited in claim 18, further comprising:

controlling a flow rate of plasma processing gas through each of the multiple gas supply zones to control a plasma density across the semiconductor wafer.

20. The method as recited in claim 18, wherein the multiple independently controllable gas supply zones are concentrically defined across the gas distribution unit.

21. The method as recited in claim 13, further comprising:

receiving the exhaust flow of plasma processing gas from the gas distribution unit to an exhaust region;

operating a pump to provide a suction force to a valve fluidly connected to the exhaust region; and

operating the valve to control an exhaust flow from the plasma generation volume through the gas distribution unit.