Tridimensional structures for an ink jet printhead and relevant manufacturing process
AssigneeTelecom Italia S.p.A.
InventorsFulvio Cominetti, Luigina Gino
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Abstract
In a monolithic ink jet printhead, a structural layer is made comprising cavities, obtained from the polymerization of a solution of a monomer, or an oligomer, and a photointiator; during the polymerization by radiation, acid species are unduly generated in zones protected by a mask, due to reflection of the radiation on reflecting surfaces of the support of the sructural layer; these acid species cause undue polymerization of the solution on the inside of the cavities to oppose the formation of these acid species, a polymerzation inhibitor basic compound is used.
Claims12
A photolithographic process for producing tridimensional structures in a structural layer in photopolymer for an ink jet printhead, said tridimensional structures being made on a substrate having a bottom wall at least in part reflecting, and comprising at least a side wall adjacent to said bottom wall, said process comprising:
- depositing on said substrate a photopolymerizable layer comprising a solution of a monomer or oligomer, a photoinitiator, and a polymerization inhibitor basic compound in a quantity less than the stoichiometric value corresponding to the complete neutralization of the acid species generated by the photoinitiator;
- masking said layer for defining areas protected by said masking and areas not protected by said masking, intended to make said tridimensional structures;
- irradiating with an ultraviolet (UV) radiation for generating acid species suitable for promoting the polymerization of said solution in said areas not protected by said masking;
- in which a fraction of said radiation is reflected by said reflecting part on the inside of said areas protected by the masking, unwanted acid species being generated in a quantity corresponding to said fraction of radiation, on account of said reflected radiation;
- neutralizing said unwanted acid species by means of said inhibitor basic compound;
- removing said unpolymerized photopolymerizable solution from said areas protected by said masking.
A photolithographic process for producing tridimensional structures in a structural layer in photopolymer for an ink jet printhead, said tridimensional structures being made on a substrate having a bottom wall at least in part reflecting, and comprising at least a side wall adjacent to said bottom wall, said process comprising:
- depositing on said substrate a photopolymerizable layer comprising a solution of a monomer or oligomer, a photoinitiator, and a polymerization inhibitor basic compound in a quantity less than the stoichiometric value corresponding to the complete neutralization of the acid species generated by the photoinitiator, wherein said polymerization inhibitor comprises tris-(2-hydroxy-1-propyl)amine;
- masking said layer for defining areas protected by said masking and areas not protected by said masking, intended to make said tridimensional structures;
- irradiating with an ultraviolet (UV) radiation for generating acid species suitable for promoting the polymerization of said solution in said areas not protected by said masking;
- in which a fraction of said radiation is reflected by said reflecting part on the inside of said areas protected by the masking, unwanted acid species being generated in a quantity corresponding to said fraction of radiation, on account of said reflected radiation;
- neutralizing said unwanted acid species by means of said inhibitor basic compound;
- removing said unpolymerized photopolymerizable solution from said areas protected by said masking.
A photolithographic process for producing tridimensional structures in a structural layer in photopolymer for an ink jet printhead, said tridimensional structures being made on a substrate having a bottom wall at least in part reflecting, and comprising at least a side wall adjacent to said bottom wall, said process comprising:
- depositing on said substrate a photopolymerizable layer comprising a solution of a monomer or oligomer, a photoinitiator, and a polymerization inhibitor basic compound in a quantity less than the stoichiometric value corresponding to the complete neutralization of the acid species generated by the photoinitiator, wherein said polymerization inhibitor has a coefficient of acidity of the conjugate acid (pKa) that is between 5 and 11;
- masking said layer for defining areas protected by said masking and areas not protected by said masking, intended to make said tridimensional structures;
- irradiating with an ultraviolet (UV) radiation for generating acid species suitable for promoting the polymerization of said solution in said areas not protected by said masking;
- in which a fraction of said radiation is reflected by said reflecting part on the inside of said areas protected by the masking, unwanted acid species being generated in a quantity corresponding to said fraction of radiation, on account of said reflected radiation;
- neutralizing said unwanted acid species by means of said inhibitor basic compound;
- removing said unpolymerized photopolymerizable solution from said areas protected by said masking.
Dependencies are inferred from the claim text.