Gas distribution system for ceramic showerhead of plasma etch reactor

• US 10,366,865 B2
• Filed: 01/25/2016
• Issued: 07/30/2019
• Est. Priority Date: 05/31/2011
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Kang, Michael, Paterson, Alex
• Primary Examiner(s): Lund, Jeffrie R
• Assistant Examiner(s): Antolin, Stanislav
• Application Number:
  US15/005,877
• Publication Number:
  US 20160217977A1
• Time in Patent Office: 1,282 Days
• CPC Class Codes: B01F 35/7182 with means for feeding the material with a fractal or tree-type distribution in a surface
• CPC Class Codes: C23C 16/45561 Gas plumbing upstream of the reaction chamber
• CPC Class Codes: C23C 16/45563 Gas nozzles
• CPC Class Codes: C23C 16/4558 Perforated rings
• CPC Class Codes: H01J 2237/006 Details of gas supplies, e.g. in an ion source, to a beam line, to a specimen or to a workpiece, H01J37/3244 takes precedence; environmental cells for electron microscopes H01J2237/2003; microscopes with environmental specimen chamber H01J2237/2608
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/3211 Antennas, e.g. particular shapes of coils
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32642 Focus rings
• CPC Class Codes: H01L 21/30655 comprising alternated and repeated etching and passivation steps, e.g. Bosch process
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: Y10T 137/0402 Cleaning, repairing, or assembling
• CPC Class Codes: Y10T 137/85938 Non-valved flow dividers

Abstract

A gas delivery system for a ceramic showerhead includes gas connection blocks and a gas ring, the gas connection blocks mounted on the gas ring such that gas outlets in the blocks deliver process gas to gas inlets in an outer periphery of the showerhead. The gas ring includes a bottom ring with channels therein and a welded cover plate enclosing the channels. The gas ring can include a first channel extending ½ the length of the gas ring, two second channels connected at midpoints thereof to downstream ends of the first channel, and four third channels connected at midpoints thereof to downstream ends of the second channels. the cover plate can include a first section enclosing the first channel, two second sections connected at midpoints thereof to ends of the first section, and third sections connected at midpoints thereof to ends of the second sections. The channels are arranged such that the process gas travels equal distances for a single gas inlet in the gas ring to eight outlets in the cover ring allowing equal gas flow.

Claims

1. A gas delivery ring configured to supply process gas to an outer periphery of a showerhead of a plasma processing apparatus wherein a semiconductor substrate supported on a substrate support is subjected to plasma processing, the gas delivery ring comprising:

a gas ring having a single gas inlet, a plurality of channels, and a plurality of gas outlets in fluid communication with the gas inlet via the channels;

the channels including a first channel connected to the gas inlet at a midpoint thereof with downstream ends of the first channel equidistant from the gas inlet and from each other, two second channels connected at midpoints thereof to the downstream ends of the first channel with downstream ends of the second channels equidistant from the downstream ends of the first channel and from each other, and four third channels connected at midpoints thereof to downstream ends of the second channels with downstream ends of the third channels connected to the gas outlets; and

a bottom ring and cover ring, the channels extending into an upper surface of the bottom ring and enclosed by the cover ring,

wherein an upper surface of the gas delivery ring includes mounting surfaces having mounting holes therein configured to receive fasteners of gas connection blocks which attach the gas delivery ring to the outer periphery of the showerhead, and wherein the channels are disposed within the same plane.

2. The gas delivery ring of claim 1, wherein the gas delivery ring includes free ends equidistant from the midpoint of the first channel.

3. The gas delivery ring of claim 2, wherein an extension limiter connects the free ends of the gas delivery ring.

4. The gas delivery ring of claim 1, wherein the gas outlets are in an upper surface of the cover ring.

5. The gas delivery ring of claim 1, wherein surfaces of the channels are coated with a silicon coating.

6. The gas delivery ring of claim 1, wherein the channels are rounded at locations where the ends of the first channel are connected to midpoints of the second channels and where the ends of the second channels are connected to the third channels, and downstream ends of the third channels are angled inwardly and include rounded ends.

7. The gas delivery ring of claim 1, wherein the gas inlet is on an outer periphery of the gas delivery ring and an L-shaped channel extends between the gas inlet and the midpoint of the first channel.

8. The gas delivery ring of claim 1, wherein the cover ring is welded to the bottom ring, the gas outlets are located on a radius of about 10 to 11 inches from a center of the gas delivery ring, the channels are rectangular in cross section with a width of about 0.1 inch and height of about 0.32 inch, the cover ring has a thickness of about 0.03 inch and is located in a recess in an upper surface of the bottom ring, the recess having a width of about 0.12 inch along opposite sides of the channels.