Diazonaphthoquinone
Encyclopedia
Diazonaphthoquinone is a diazo
derivative of naphthoquinone
. Upon exposure to light, it undergoes a Wolff rearrangement
to form a ketene. This chemical reaction is exploited with a variety of diazonaphthoquinone derivatives in the semiconductor industry.
Diazonaphthoquinone sulfonic acid esters are commonly used as components of photoresist
materials for semiconductor manufacturing. In this application DNQs are mixed with Novolac resin, a type of phenol
ic polymer
. The DNQ functions as a dissolution inhibitor. During the masking/patterning process, portions of the photoresist film are exposed to light while others remain unexposed. In the unexposed regions of the resist film, the DNQ acts as a dissolution inhibitor and the resist remains insoluble in the aqueous base developer. In the exposed regions, the DNQ forms a ketene, which, in turn, reacts with ambient water to form a base soluble indene carboxylic acid. The exposed regions of the photoresist film become soluble in aqueous base; thus allowing the formation of a relief image during development.
Diazo
Diazo refers to a type of organic compound called diazo compound that has two linked nitrogen atoms as a terminal functional group. The general formula is R2C=N2. The simplest example of a diazo compound is diazomethane...
derivative of naphthoquinone
Naphthoquinone
Naphthoquinone is a class of natural phenols based on the C6-C4 skeleton.1,4-Naphthoquinone can be viewed as derivatives of naphthalene through the replacement of two hydrogen atoms by two ketone groups....
. Upon exposure to light, it undergoes a Wolff rearrangement
Wolff rearrangement
The Wolff rearrangement is a rearrangement reaction converting a α-diazo-ketone into a ketene. This reaction was first reported by Ludwig Wolff in 1912....
to form a ketene. This chemical reaction is exploited with a variety of diazonaphthoquinone derivatives in the semiconductor industry.
Diazonaphthoquinone sulfonic acid esters are commonly used as components of photoresist
Photoresist
A photoresist is a light-sensitive material used in several industrial processes, such as photolithography and photoengraving to form a patterned coating on a surface.-Tone:Photoresists are classified into two groups: positive resists and negative resists....
materials for semiconductor manufacturing. In this application DNQs are mixed with Novolac resin, a type of phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...
ic polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
. The DNQ functions as a dissolution inhibitor. During the masking/patterning process, portions of the photoresist film are exposed to light while others remain unexposed. In the unexposed regions of the resist film, the DNQ acts as a dissolution inhibitor and the resist remains insoluble in the aqueous base developer. In the exposed regions, the DNQ forms a ketene, which, in turn, reacts with ambient water to form a base soluble indene carboxylic acid. The exposed regions of the photoresist film become soluble in aqueous base; thus allowing the formation of a relief image during development.