Reducing backside deposition in a substrate processing apparatus through the use of a shadow ring

A processing reactor, comprising:

• a processing chamber receiving processing gas in an upper portion thereof for processing a substrate;
• a pedestal for supporting said substrate in said upper portion;
• a shadow ring engaging an upper periphery of said substrate and forming a cavity between itself and said pedestal in a vicinity of said periphery;
• a purge fluid supply for supplying a purge fluid to said cavity;
• and
• a plurality of fluid paths extending from said cavity to a lower portion of said chamber.

A processing reactor, comprising;

• a processing chamber receiving processing gas in an upper portion thereof for processing a substrate;
• a pedestal for supporting said substrate in said upper portion;
• and
• a ring member having a lip portion engaging an upper periphery of said substrate and a body portion extending outwardly from said lip portion and having a lower surface facing said pedestal;
• wherein a facing portion of said pedestal facing said lower surface of said body portion of said ting member is formed with a plurality of circumferential grooves.

A method of chemical vapor deposition, comprising the steps of:

• supporting a substrate on a pedestal in a chamber:
• covering an upper periphery of said substrate with a ring member extending outwardly from an outer periphery of said substrate, said ring member being placed such that a cavity is formed between said pedestal and said ring member in a vicinity of said outer periphery and a circumferential gap is formed between said ring member and said pedestal that extends radially outwardly from said cavity;
• electrically heating said pedestal whereby said substrate is heated and heat flows across said gap to said ring member;
• flowing a deposition gas into a portion of said chamber overlying said substrate;
• flowing a gas into said cavity, whereby said gas flows outwardly from said cavity through said gap;
• and
• additionally flowing said gas out of said cavity through paths other than said gap.

A method of chemical vapor deposition, comprising the steps of:

• (a) supporting a substrate on a substrate support in a chamber;
• (b) covering an upper periphery of the substrate with a substrate circumscribing ring, a cavity being defined between the substrate circumscribing ring and the substrate support, at an outer periphery of the substrate, and a gap being formed between the substrate circumscribing ring and the substrate support that extends radially outward from the cavity;
• (c) heating the substrate support whereby heat flows across the gap to the substrate circumscribing ring and the substrate is heated by the substrate support and the substrate circumscribing ring;
• (d) flowing a processing gas into the chamber;
• (e) flowing a fluid into the cavity;
• and
• (f) exhausting the fluid from the cavity through at least one fluid exhaust other than the gap.