KPR, originally known as

Kodak The Eastman Kodak Company, referred to simply as Kodak (), is an American public company that produces various products related to its historic basis in film photography. The company is headquartered in Rochester, New York, and is incorporated i ...

Photoresist A photoresist (also known simply as a resist) is a light-sensitive material used in several processes, such as photolithography and photoengraving, to form a patterned coating on a surface. This process is crucial in the electronics industry. T ...

, is a

photosensitive Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicity. ...

material used in

photoengraving Photoengraving is a process that uses a light-sensitive photoresist applied to the surface to be engraved to create a mask that protects some areas during a subsequent operation which etches, dissolves, or otherwise removes some or all of the ma ...

Photogravure Photogravure (in French ''héliogravure'') is a process for printing photographs, also sometimes used for reproductive intaglio printmaking. It is a photo-mechanical process whereby a copper plate is grained (adding a pattern to the plate) and ...

and

photolithography Photolithography (also known as optical lithography) is a process used in the manufacturing of integrated circuits. It involves using light to transfer a pattern onto a substrate, typically a silicon wafer. The process begins with a photosensiti ...

. Once dried, KPR can be dissolved by several solvents. However, after exposure to strong

ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...

light, it hardens and becomes insoluble by some of these solvents. It is also resistant to

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

ferric chloride Iron(III) chloride describes the inorganic compounds with the formula (H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated f ...

and other chemicals used to etch metals. The fundamental method of its use was first described in two US Patents, USP 2610120 and USP 2670287, assigned to the

Eastman Kodak Company The Eastman Kodak Company, referred to simply as Kodak (), is an American public company that produces various products related to its historic basis in film photography. The company is headquartered in Rochester, New York, and is incorporated i ...

Rochester, New York Rochester is a city in and the county seat, seat of government of Monroe County, New York, United States. It is the List of municipalities in New York, fourth-most populous city and 10th most-populated municipality in New York, with a populati ...

. These photo-resistant resins are formed from cinnamic acid esters, with the most preferable being polyvinyl cinnamate. While they were developed primarily for photolithography for high-speed print setting for uses such as newspaper printing, their perhaps highest value came from their ability to produce non-conducting layers on top of conducting layers to precise dimensions. This enabled the "printing" of large scale, closely placed conductive and non-conductive pathways to create binary gates. These were semi-conductors or the means to create semiconductors. This technology was utilized heavily by the Shockley 8, at the original Fairchild Semiconductor to produce more and more closely spaced semiconductors for computing. It is ironic that Kodak, the original patent assignee, did not really participate in the economic juggernaut that it created through this lithographic printing technology.

References

Kodak {{photo-stub