Method of sputter deposition

A method for forming a plasma within a reaction chamber, comprising the following steps:

• flowing argon gas through the reaction chamber at an argon gas flow rate and forming a plasma within the reaction chamber from the argon gas, the argon gas being initially flowed through the reaction chamber at an initial argon gas flow rate;
• flowing a mixing gas comprising at least one of helium gas and neon gas through the reaction chamber at a mixing gas flow rate, the mixing gas being incorporated into the plasma, the combined mixing gas flow rate and argon gas flow rate comprising at least part of a total gas flow rate;
• after flowing the mixing gas through the reaction chamber, reducing the argon gas flow rate and determining if the plasma has been extinguished;
• if the plasma has not been extinguished, further reducing the argon gas flow rate and again determining if the plasma has been extinguished, the steps of reducing the argon gas flow rate and determining if the plasma has been extinguished being repeated until the plasma is extinguished;
• if the plasma is extinguished, re-forming the plasma at an increased mixing gas flow rate and at about the initial argon gas flow rate;
• after re-forming the plasma, repeating the steps of reducing the argon gas flow rate and determining if the plasma has been extinguished until the plasma is extinguished;
• after extinguishing the re-formed plasma, determining if the total gas flow rate at which the re-formed plasma was extinguished is greater than the total gas flow rate at which the plasma was extinguished prior to increasing the mixing gas flow rate;
• if the total gas flow rate at which the re-formed plasma was extinguished is not greater than the total gas flow rate at which the plasma was extinguished prior to increasing the mixing gas flow rate, in at least one iteration, repeating the steps of 1) increasing the mixing gas flow rate, 2) re-forming the plasma, 3) reducing the argon flow until the re-formed plasma is extinguished, and 4) determining if the total gas flow rate at which the re-formed plasma is extinguished is greater than the total gas flow rate at which the plasma was extinguished prior to increasing the mixing gas flow rate;
• and
• if the total gas flow rate at which the re-formed plasma is extinguished is greater than the total gas flow rate at which the plasma was extinguished prior to increasing the mixing gas flow rate, establishing and maintaining a substantially stable plasma at about the mixing gas flow rate at which the total gas flow rate was minimized and at about the lowest argon gas flow rate which will maintain the substantially stable plasma.

A method for forming a plasma within a reaction chamber, comprising the following steps:

• (a) performing at least two iterations of the following steps (i) through (iv), with each iteration terminating when a plasma reaches a predetermined degree of instability, and with at least one of the iterations comprising a higher mixing gas flow rate than at least one other iteration;
• (i) flowing argon gas through the reaction chamber at an argon gas flow rate and forming a plasma within the reaction chamber from the argon gas;
• (ii) flowing a mixing gas comprising at least one of helium gas and neon gas through the reaction chamber at a mixing gas flow rate, the mixing gas being incorporated into the plasma, the combined mixing gas flow rate and argon gas flow rate comprising at least part of a total gas flow rate;
• (iii) reducing the argon gas flow rate by an argon flow reduction amount;
• and
• (iv) determining if the plasma has reached a predetermined degree of instability;
• if the plasma has not reached the predetermined degree of instability, repeating steps (iii) and (iv);
• if the plasma has reached the predetermined degree of instability, determining a total gas flow rate at which the plasma reached the predetermined degree of instability, the total gas flow rate comprising a sum of the mixing gas flow rate and the argon gas flow rate at which the plasma reached the predetermined degree of instability;
• and
• (b) if the total gas flow rate at which the plasma reached the predetermined degree of instability in an iteration comprising a higher mixing flow rate is greater than the total gas flow rate at which the plasma reached the predetermined degree of instability in an iteration comprising a lower mixing gas flow rate, establishing and maintaining a substantially stable plasma at about the lower mixing gas flow rate and at about a lowest argon gas flow rate which will maintain the substantially stable plasma to thereby form a substantially stable plasma at substantially minimized pressure within the reaction chamber.

A method for sputter deposition of a metal onto a semiconductor material, the method comprising the following steps:

• providing a substrate of semiconductor material within a reaction chamber;
• providing a metal target having an erodable surface within the reaction chamber;
• providing a gaseous mixture comprising argon gas and at least one of helium gas and neon gas within the reaction chamber;
• forming a plasma from said gaseous mixture within the reaction chamber, the plasma, having plasma components including argon;
• impacting plasma components onto the erodable surface of the metal target to sputter target atoms therefrom, the sputtered target atoms having a mean free path, a ratio of argon to other plasma components being selected to substantially maximize the mean free path;
• and
• depositing the sputtered target atoms onto the substrate.

A method for substantially maximizing the mean free path of sputtered target atoms within a reaction chamber, comprising the following steps:

• providing a target within the reaction chamber, the target having target atoms;
• providing a gaseous mixture within the reaction chamber, the gaseous mixture comprising argon gas and at least one of helium gas and neon gas, and thereby comprising a ratio of argon gas in the gaseous mixture;
• forming a plasma from the gaseous mixture within the reaction chamber, the plasma having plasma components including argon;
• and
• impacting the plasma components with the target to sputter target atoms therefrom, the ratio of argon to other plasma components being selected to substantially maximize the mean free path of the sputtered target atoms.