Forming partial-depth features in polymer film

A method of forming a partial-depth feature in a polymer film on a semiconductor wafer using exposure tools having a critical dimension, comprising the steps of:

• (a) disposing on a photomask a partial-depth producing pattern including a plurality of areas of UV light-blocking material, each area having a smaller dimension less than the critical dimension and being spaced apart a distance less than the critical dimension;
• and
• (b) exposing the polymer film to the partial-depth producing pattern on the photomask in a manner substantially the same as when exposing the polymer film to full-depth producing images on the photomask;
• and
• (c) developing the polymer film exposed to the partial-depth producing pattern on the photomask in a manner substantially the same as when developing the polymer film exposed to a full-depth producing pattern on the photomask.

A method of altering an optical property of a surface of a polymer film, comprising the steps of:

• (a) disposing a layer of polymer film on a semiconductor wafer, the layer having a surface with a first optical property;
• (b) exposing the polymer film to a partial-depth producing pattern on a photomask;
• and
• (c) developing the exposed polymer film such that the surface of the polymer film has a second optical property.

A method to inscribe markings on a surface of a polymer film, comprising the steps of:

• (a) disposing a layer of polymer film on a semiconductor wafer, the layer having a surface with no discernable markings;
• (b) exposing the polymer film to a partial-depth producing pattern on a photomask, the partial-depth producing pattern having one or more preselected shapes;
• and
• (c) developing the exposed polymer film such that the one or more preselected shapes are discernable on the surface of the polymer film.

A method of making thinner a layer of a polymer film disposed on a semiconductor wafer, comprising the steps of:

• (a) providing a layer of polymer film on the semiconductor wafer, the layer having a first thickness;
• (b) exposing at least a portion of the polymer film to a partial-depth producing pattern on at least a portion of a photomask;
• and
• (c) developing the polymer film such that the at least a portion of the polymer film exposed to the partial-depth producing pattern has a second thickness, the second thickness being smaller than the first thickness.

A method of using a photomask to form a feature in a layer of a negative-acting photo-imageable polymer film, the feature having a smaller dimension greater than a critical dimension of photolithography tools used, and in which the feature penetrates only partially through the layer, the polymer film having a minimum structurally sound material width, comprising the steps of:

• (a) disposing on the photomask a plurality of areas of chrome, each area having a smaller dimension smaller than the critical dimension and being spaced apart a distance smaller than the critical dimension;
• (b) exposing the polymer film to UV light shining through the photomask such that the UV light is blocked by the areas of chrome;
• and
• (c) developing the polymer film such that portions of the polymer film not exposed to the UV light and portions of the polymer film exposed to the UV light and having a width narrower than the minimum structurally sound material width, are removed, thereby forming the feature.