Method for making very small isolated dots on substrates

A method for forming very small isolated dots of a target material on a substrate, the method comprising:

• providing a substrate having a layer of the target material disposed on a surface thereof;
• forming a layer of a first hard etch masking material on a surface of the target material;
• forming a first layer of a photoresist material over a surface of the first hard etch material layer;
• exposing the first photoresist layer to light through a mask to define a plurality of lines therein, the lines extending in a first direction;
• developing the first photoresist layer to form a plurality of first photoresist lines on the surface of the first hard etch material layer;
• selectively etching the layer of first hard etch masking material using the first photoresist lines as an etch mask so as to remove all of the first hard etch masking material from the substrate except for that underlying the photoresist lines and defining lines of the first hard etch masking material on the substrate;
• removing the photoresist lines from the substrate;
• forming a layer of a second hard etch masking material over the surface of the substrate;
• selectively etching the layer of the second hard etch masking material so as remove all of the second hard etch masking material except for a plurality of first rounded linear spacers respectively disposed on opposite sides of the lines of the first hard etch masking material and extending in the first direction;
• removing the lines of the first hard etch masking material from the substrate;
• selectively etching the layer of target material using the first linear spacers as an etch mask so as to form a plurality of lines of the target material underlying the first spacers and extending in the first direction on the substrate;
• and,
• removing the first linear spacers from the substrate.