Collimated deposition apparatus and method

A method of depositing a step coating on a workpiece, comprising the steps

• supporting the workpiece in a stationary position in a chamber,
• emitting particles from a sputter source substantially uniformly throughout an area of greater lateral extent than the workpiece, so that at least some of said particles will be deposited on said workpiece, the individual deposited particles impinging on the surface of the workpiece at angles of incidence,
• passing the particles through a collimating filter having a plurality of transmissive cells with a length to diameter ratio defining an aspect ratio in the range of 1:1 to 3:1 positioned between the source and the workpiece to limit the angles of incidence at which the particles can impinge upon the workpiece,
• maintaining pressure within the chamber at a level which is sufficiently low to prevent substantial scattering of the particles between the collimating filter and the workpiece, and
• changing the length to diameter ratio of the collimating filter cells as the coating builds up on the workpiece.

A method of depositing a step coating on a workpiece, comprising the steps

• supporting the workpiece in a stationary position in a chamber,
• emitting particles from a sputter source substantially uniformly throughout an area of greater lateral extend than the workpiece, so that at least some of said particles will be deposited on said workpiece, the individual deposited particles impinging on the surface of the workpiece at angles of incidence,
• passing the particles through a collimating filter having a plurality of transmissive cells with a length to diameter ratio defining an aspect ratio in the range of 1:1 to 3:1 positioned between the source and the workpiece to limit the angles of incidence at which the particles can impinge upon the workpiece,
• maintaining pressure within the chamber at a level which is sufficiently low to prevent substantial scattering of the particles between the collimating filter and the workpiece, and
• moving the collimating filter in a direction parallel to the source and the workpiece as the coating builds up the workpiece.

A method of depositing a step coating on a workpiece, comprising the steps of:

• preheating the workpiece to a first elevated temperature,
• depositing an initial coating on the workpiece by sputtering at a first rate for a first predetermined period of time,
• on the workpiece by sputtering at a second rate for a second predetermined period of time, said second predetermined period of time being longer in duration than said first predetermined period of time, and said second rate of sputtering being slower than said first rate,
• increasing the temperature of the workpiece from the first temperature to a second, higher temperature, and
• depositing an additional coating on the workpiece by sputtering while the temperature of said workpiece is being increased.

Sputtering apparatus for depositing a step coating in an opening in a workpiece, said opening having an aspect ratio comprising:

• a chamber,
• means for supporting the workpiece in the chamber,
• a sputter source for emitting particles for forming the coating on the workpiece, so that at least some of said particles will be deposited on said workpiece, the individual deposited particles impinging on the surface of the workpiece at angles of incidence,
• a particle collimating filter having a plurality of transmissive cells positioned between the source and the workpiece for limiting the angles of incidence at which the particles can impinge upon the workpiece, wherein the cells of the collimating filter are formed in two sections which are movable axially relative to each other to change the length to diameter ratio of the cells, and
• means for adjusting the filter so that the cells have a length to diameter ratio which may be varied.

A method of depositing a step coating in an opening in a workpiece having an aspect ratio which changes as the coating builds up therein, comprising the steps of:

• supporting the workpiece in a chamber,
• emitting particles from a sputter source for forming the coating on the workpiece, so that at least some of said particles will be deposited on said workpiece, the individual deposited particles impinging on the surface of the workpiece at angles of incidence,
• passing the particles from the source to the workpiece through a collimating filter having a plurality of transmissive cells positioned between the source and the workpiece to limit the angles of incidence at which the particles impinge upon the workpiece, and
• adjusting the filter so that the cells have a length to diameter ratio which changes with the aspect ratio of the opening as the coating builds in the opening.

A method of depositing a step coating in an opening in a workpiece having an aspect ratio which changes as the coating builds up therein, comprising the steps of:

• supporting the workpiece in a chamber,
• establishing a first subatmospheric gas pressure within the chamber,
• emitting particles from a sputter source for forming the coating on the workpiece, so that at least some of said particles will be deposited on said workpiece, the individual deposited particles impinging on the surface of the workpiece at angles of incidence,
• passing the particles from the source to the workpiece through a collimating filter having a plurality of transmissive cells with a length to diameter ratio greater than the aspect ratio of the opening to limit the angles of incidence at which the particles impinge upon the workpiece, and
• reducing the pressure in the chamber as the coating builds up in the opening.