UV radiation blocking protective layers compatible with thick film pastes
AssigneeE.I. du Pont de Nemours and Company
InventorsYoung H. Kim, Gann Xu
Life of this patent
Estimating the term…
Abstract
This invention relates to novel compositions comprising a protective polymer layer and a UV blocking agent. This is used in the fabrication of electronic devices using thick film pastes. The present invention is also an electronic device fabrication process using the compositions. The protective polymer layer is fabricated from materials, which are insoluble after irradiation in the ester-type solvents contained in the thick film paste. By appropriate selection of protective film polymers, the protective film can be compatible with the thick film paste and can be further used to shield portions of the thick film paste from UV irradiation.
Claims9
A process for fabricating an electronic device that comprises a substrate, comprising:
- (a) forming a protective layer on a first side of the substrate from a composition that comprises;
- (i) a UV blocking agent selected from the group consisting of 2 hydroxyl aryl benzotriazole and its derivatives, and 2 hydroxy benzophenone and its derivatives;
- and
- (ii) a polymer in which at least 50 mole percent of the monomers in the polymer comprise one or more of the structures (i), (ii) and (iii) described as follows:
- where R1 is hydrogen or lower alkyl;
- R2 is a lower alkyl;
- and R3 is hydrogen or a lower alkyl, where the definition of lower alkyl includes alkyl groups having 1 to 6 linear or cyclic carbon atoms;
- where R1 is hydrogen or lower alkyl;
- R2 is a lower alkyl;
- and R3 and R4 are independently hydrogen or a lower alkyl, where the definition of lower alkyl includes alkyl groups having 1 to 6 carbon atoms and the joining of R1 and R2, or R1 and either R3 or R4, or R2 and either R3 or R4 to form a 5-, 6-, or 7-membered ring;
- and
- where R1 is hydrogen or lower alkyl;
- R2 is a lower alkyl;
- and R3 and R4 are independently hydrogen or a lower alkyl;
- where the definition of lower alkyl includes alkyl groups having 1 to 6 carbon atoms and the joining of R1 and R2, or R1 and either R3 or R4, or R2 and either R3 or R4 to form a 5-, 6-, or 7-membered ring;
- and where n is 0 to 4;
- (b) irradiating the protective layer through a mask;
- (c) heating the device;
- (d) contacting the protective layer with a developing solution to remove the portions of the protective layer composition exposed to radiation in step (b), and thereby form a patterned protective layer;
- (e) irradiating the patterned protective layer;
- (f) heating the device;
- (g) applying to the patterned protective layer a paste composition;
- (h) irradiating the device from a second side of the substrate to form a pattern in the paste composition;
- and
- (i) contacting the paste composition and the patterned protective layer with a developing solution to remove (I) the portions of the paste composition not exposed to radiation in step (h), and (II) the patterned protective layer.
Dependencies are inferred from the claim text.