Substrate processing systems including gas delivery system with reduced dead legs

A gas delivery system for a substrate processing system, comprising:

• a 2-port valve including:
• a first port and a second port;
• and
• a first valve located between the first port and the second port;
• a 4-port valve including:
• a first port, a second port, a third port and a fourth port;
• a first node connected to the first port and the second port;
• a bypass path located between the third port and the fourth port;
• a second node located along the bypass path between the third port and the fourth port;
• and
• a second valve located between the first node and the second node;
• a manifold block defining gas flow channels:
• configured to connect the first port of the 4-port valve to a first inlet;
• configured to connect the second port of the 4-port valve to the first port of the 2-port valve;
• configured to connect the third port of the 4-port valve to a second inlet;
• configured to connect the second port of the 2-port valve to a first outlet;
• and
• configured to connect the fourth port of the 4-port valve to a second outlet;
• wherein the second port of the 4-port valve connects at the first node at an angle between 60 and 120 degrees relative to the first port of the 4-port valve.