Dry film formulation

1. An improved photoimageable dry film formulation, the dry film formulation comprising a multifunctional epoxy compound, a photoinitiator capable of generating a cation, a non-photoreactive solvent, and from about 0.5 to about 5% by weight a silane oligomer adhesion enhancer based on a total weight of the photoimageable dry film formulation before drying, wherein the silane oligomer adhesion enhancer is a gamma-glycidoxypropyltrimethoxysilane oligomer of the formula

wherein n ranges from 1 to 4.

2. The improved photoimageable dry film formulation of claim 1 , wherein the formulation comprises from about 1 to about 3 wt. % of the silane oligomer adhesion enhancer based on a total weight of the photoimageable dry film formulation before drying.

3. The improved photoimageable dry film formulation of claim 1 , wherein the solvent comprises an aliphatic ketone solvent.

4. The improved photoimageable dry film formulation of claim 3 , wherein the aliphatic ketone solvent comprises cyclohexanone, and optionally, acetone.

5. The improved photoimageable dry film formulation of claim 1 , wherein a dry film laminate made from the photoimageable dry film formulation is applied to a silicon semiconductor substrate.

6. The improved photoimageable dry film formulation of claim 1 , wherein a dry film laminate made from the photoimageable dry film formulation is applied to a flow feature layer of a fluidic ejection head.

7. A method for making an improved fluidic ejection head, the method comprising the steps of:

applying a photoresist layer to a release film, wherein the photoresist layer is derived from a photoimageable dry film formulation comprising a multi-functional epoxy compound, a photoacid generator, a silane oligomer adhesion enhancer is a gamma-glycidoxypropyltrimethoxysilane oligomer of the formula

wherein n ranges from 1 to 4, and an aryl ketone solvent;

drying the photoimageable dry film formulation on the release film layer to provide a thick film layer;

laminating the thick film layer to a flow feature layer on a semiconductor substrate;

removing the release film from the thick film layer;

imaging a nozzle hole in the thick film layer; and

developing the imaged thick film layer to provide a nozzle plate for the fluidic ejection head.

8. The method of claim 7 , wherein the photoimageable dry film formulation comprises from about 1 to about 3 wt. % of the silane oligomer adhesion enhancer based on a total weight of the photoimageable dry film formulation before drying.

9. The method of claim 7 , wherein the solvent comprises an aliphatic ketone solvent.

10. The method of claim 9 , wherein the aliphatic ketone solvent comprises cyclohexanone, and optionally, acetone.

11. The method of claim 7 , wherein the photoresist composition on the release film is dried at a temperature ranging from about 110° to about 150° C.

12. A fluidic ejection head for ejecting a fluid composition comprising:

a semiconductor substrate containing fluid ejection devices thereon,

a flow feature layer disposed on the semiconductor substrate, and

a thick film layer laminated to the flow feature layer, wherein the thick film layer is derived from a photoimageable dry film formulation comprising a multifunctional epoxy compound, a photoinitiator capable of generating a cation, a non-photoreactive solvent, and from about 0.5 to about 5% by weight a silane oligomer adhesion enhancer based on a total weight of the photoimageable dry film formulation before drying, wherein the silane oligomer adhesion enhancer is a gamma-glycidoxypropyltrimethoxysilane oligomer of the formula

wherein n ranges from 1 to 4.

13. The fluidic ejection head of claim 12 , wherein the photoimageable dry film formulation comprises from about 1 to about 3 wt. % of the silane oligomer adhesion enhancer based on a total weight of the photoimageable dry film formulation before drying.

14. The fluidic ejection head of claim 12 , wherein the solvent comprises cyclohexanone, and optionally, acetone.