Gas distribution blocker apparatus

A processing apparatus, comprising:

• a backing plate having an orifice disposed therethrough and in fluid communication with a gas source;
• a showerhead positioned adjacent the showerhead such that a plenum is formed between the backing plate and the showerhead, wherein the showerhead has a plurality of gas passages disposed therethrough;
• and
• a blocker member having a plurality of gas passages disposed therethrough and coupled to the showerhead such that a first gas passage disposed through the showerhead is aligned with a gas passage disposed through the blocker member and a second gas passage disposed through the showerhead is blocked by the blocker member.

A processing apparatus, comprising:

• a backing plate having an orifice formed therethrough and in fluid communication with a gas source;
• a showerhead having a plurality of apertures formed therethrough and coupled to the backing plate;
• a blocker member having a side with a plurality of gas passages formed therethrough and a bottom having a plurality of gas passages formed therethrough, wherein the blocker member is disposed between a central region of the backing plate and a central region of the showerhead;
• and
• a spacer member coupled to the blocker member.

A method for depositing thin films, comprising:

• introducing a gas mixture into a first plenum formed between a backing plate and a blocker member of a processing apparatus;
• allowing the gas mixture to diffuse through the blocker member into a second plenum disposed between the blocker member and a showerhead;
• depositing a thin film on a substrate;
• determining the uniformity of the thin film deposited on the substrate;
• adjusting the volume of the first plenum with respect to the volume of the second plenum;
• and
• depositing a second thin film on a second substrate.