Method of fabricating small dimensioned lens elements and lens arrays using surface tension effects

A method of fabricating at least one lens with improved surface smoothness, the method comprising the step of:

• providing a substrate with a material layer on the substrate,
• making a hole in the material layer,
• providing a material from which the lens is to be made,
• depositing the lens material into the hole in the material layer,
• removing a portion of the substrate under the hole in which the lens material has been deposited,
• heating the substrate to a temperature at which the lens material becomes molten and changes its shape to a lens shape based on a surface tension and contact angle between the lens material and the material layer with which it is in contact, and
• cooling the material layer and the lens material to room temperature to solidify the lens material and retain the lens shape,
• the shape of the lens being determined by a surface tension and contact angle between the heated lens material and material layer in contact with the lens material, and
• the lens material being ruthenium so that the lens is to be used in an extreme ultraviolet application.

A method of fabricating an array of lenses with improved surface smoothness, the method comprising the steps of:

• providing a substrate with a material layer,
• making a plurality of holes in the material layer,
• providing a material from which the lenses comprising the array are to be made,
• depositing the lens material into the plurality of holes in the material layer,
• removing a portion of the substrate under the plurality of holes in which the lens material has been deposited, such that only the material layer surrounding the lens material is in contact with a perimeter of the lens material,
• heating the substrate to a temperature at which the lens material becomes molten and changes its shape to one of a plurality of lens shapes with its optical surfaces not contacted by the substrate, and
• cooling the material layer and the lens material to room temperature to solidify the lens material and retain the lens shape,
• the shape of the lenses and it optical surfaces being determined by a surface tension and contact angle between the heated lens material and the surrounding material layer in contact with the lens material.

A method of fabricating an array of lenses with improved surface smoothness, the method comprising the steps of:

• providing a substrate with a material layer,
• making a plurality of holes in the material layer,
• providing a material from which the lenses comprising the array are to be made,
• depositing the lens material into the plurality of holes in the material layer,
• removing a portion of the substrate under the plurality of holes in which the lens material has been deposited,
• heating the material to a temperature at which the lens material becomes molten and changes its shape to a lens shape based on a surface tension and contact angle between the lens material and the substrate with which it is in contact, and
• cooling the material layer and the lens material to room temperature to solidify the lens material and retain the lens shape,
• the shape of the lenses being determined by a surface tension and contact angle between the heated lens material and material layer in contact with the lens material, and
• the lens material being ruthenium so that the lens is to be used in an extreme ultraviolet application.

A method of fabricating a lens with first and second lens surfaces and improved surface smoothness, the method comprising the steps of:

• providing a substrate,
• making a hole through the substrate,
• providing a material from which the lens is to be made,
• depositing the lens material into the hole in the substrate, whereby only a perimeter of the lens material is in contact with the substrate,
• heating the substrate to a temperature at which the lens material becomes molten and changes its shape to one of a plurality of lens shapes with first and second optical surfaces not contacted by the substrate, and
• cooling the substrate and the lens material to room temperature to solidify the lens material and retain the lens shape,
• the shape of the lens and its optical surfaces being determined by a surface tension and contact angle between the heated lens material and the surrounding substrate in contact with the heated lens material.