1. A method of forming a pattern with improved structural strength in a negative tone photosensitive film comprising:
(a) coating a single photosensitive solution on a substrate and baking to form a single photosensitive film,
(b) exposing said substrate with a patterned mask and first exposure dose that does not completely crosslink the photosensitive film,
(c) developing said exposed photosensitive film in an aqueous base solution, and
(d) exposing said developed photosensitive film without a mask and a second exposure dose that is higher than first exposure dose to form a saturated crosslinked network,
(e) wherein a develop time after said first exposure dose is less than required for a develop time with a single exposure method having a higher dose than said first exposure dose.
2. The method of claim 1 wherein the photosensitive solution consists of a photoinitiator and a polyamic acid or polyamic ester having a crosslinkable component in an organic solvent.
3. The method of claim 2 wherein the thickness of said photosensitive film is within a range of about 1 to about 10 microns.
4. The method of claim 2 wherein said first exposure is performed with a scanner or stepper using one or more wavelengths selected from a range of about 300 nm to about 600 nm.
5. The method of claim 1 wherein said first exposure dose is determined by a process comprising:
plotting a graph of thickness loss on the y-axis and exposure energy on the x-axis, said measurements resulting from a dose matrix of said photosensitive film on said substrate,
drawing a straight line through points on said graph at low exposure energies that preferably represent a thickness loss in the range of about 20% to about 30% and extending said line toward the x-axis,
drawing a horizontal line through points representing higher doses where film thickness loss is constant and extending said line toward the y-axis, and
drawing a first vertical line downward on said graph from the intersection point of the two aforementioned lines, said first vertical line intersecting the x-axis at the preferred first exposure dose.
6. The method of claim 5 wherein the second exposure dose is determined by drawing a second vertical line downward on said graph from the lowest energy point on said horizontal line, said second vertical line intersecting the x-axis at the preferred second dose.
7. The method of claim 1 wherein said second exposure dose is preferably from a broad band exposure tool without alignment capability and which can expose the entire substrate without stepping or scanning.
8. The method of claim 2 further comprising the step of heating the photosensitive film after said second exposure to a temperature of about 350\xb0 C. for about 1 hour to convert the polyimide precursor into a patterned polyimide.
9. The method of claim 1 wherein said photosensitive solution is a negative photoresist that consists of a photoinitiator and a polymer having a crosslinkable component in an organic solvent.
10. The method of claim 1 wherein said photosensitive solution is a negative photoresist that consists of a polyvinyl phenol, a crosslinker with acid labile groups, and a photoacid generator in an organic solvent.
11. The method of claim 9 wherein said first exposure is performed with a scanner or stepper using one or more wavelengths selected from a range of about 300 nm to about 600 nm and wherein said second exposure dose is from a broad band exposure tool without alignment capability and which can expose the entire substrate without stepping or scanning.
12. The method of claim 10 wherein said first exposure is performed with a scanner or stepper using one or more wavelengths selected from a range of about 200 nm to about 600 nm and wherein said second exposure dose is from a broad band exposure tool without alignment capability and which can expose the entire substrate without stepping or scanning.
13. A method of forming a pattern in a polyimide layer on a substrate, said polyimide is suitable as a permanent insulating layer or buffer layer in semiconductor devices or chip packaging structures, said method comprising:
(a) providing a polyimide precursor film on a substrate,
(b) coating a photosensitive solution on said polyimide precursor and baking to form a photosensitive film,
(c) exposing said substrate with a patterned mask and first exposure dose that does not completely crosslink the photosensitive film,
(d) developing said exposed substrate in an aqueous base solution,
(e) exposing said substrate without a mask and a second exposure dose that is higher than first said exposure dose to form a saturated crosslinked network,
(f) transferring the pattern through the polyimide precursor layer with a wet etch,
(g) removing the photosensitive film with a stripping process, and
(h) curing the polyimide precursor layer by baking to about 350\xb0 C. for about 1 hour to form a patterned polyimide layer,
(i) wherein a develop time after said first exposure dose is less than required for a develop time with a single exposure method having a higher dose than said first exposure dose.
14. The method of claim 13 wherein said photosensitive film is a negative tone photoresist comprised of a photoinitiator and a polymer having a crosslinkable component.
15. The method of claim 13 wherein said first exposure is performed with a scanner or stepper using one or more wavelengths selected from a range of 300 to 600 nm and preferably 365 nm or 436 nm and wherein said second exposure dose is from a broad band exposure tool without alignment capability and which has an exposure field that can cover the entire surface of said substrate.
16. The method of claim 13 wherein the develop time after said first exposure dose is less than required for the develop time with a single exposure method having a higher dose than said first exposure dose.
17. The method of claim 13 wherein the wet etch is accomplished with a dilute solution of aqueous base, preferably KOH or tetrabutyl ammonium hydroxide in water.
18. The method of claim 13 wherein said polyimide layer has approximately the same space widths and feature sizes as the pattern in said polyimide precursor.
19. A method of forming a pattern in a polyimide layer on a substrate, said polyimide is suitable as a permanent insulating layer or buffer layer in semiconductor devices or chip packaging structures, said method comprising:
(a) providing a cured polyimide film on a substrate,
(b) coating a photosensitive solution on said polyimide layer and baking to form a photosensitive film,
(d) exposing said substrate with a patterned mask and first exposure dose that does not completely crosslink the photosensitive film,
(e) developing said exposed substrate in an aqueous base to form a pattern,
(f) exposing said substrate without a mask and a second exposure dose that is higher than first said exposure dose to form a saturated crosslinked network in said pattern,
(g) transferring said pattern through the polyimide layer with a plasma etch, and
(h) removing any remaining photosensitive film with a stripping process
(i) wherein a develop time after said first exposure dose is less than required for a develop time with a single exposure method having a higher dose than said first exposure dose.
20. A method of forming a pattern in a polyimide layer on a substrate, said polyimide is suitable as a permanent insulating layer or buffer layer in semiconductor devices or chip packaging structures, said method comprising;
(a) providing a cured polyimide film on a substrate,
(b) depositing a barrier layer on said polyimide film,
(c) coating a photosensitive solution on said barrier layer and baking to form a photosensitive film,
(d) exposing said substrate with a patterned mask and first exposure dose that does not completely crosslink the photosensitive film,
(e) developing said exposed substrate in an aqueous base to form a pattern,
(f) exposing said substrate without a mask and a second exposure dose that is higher than first said exposure dose to form a saturated crosslinked network in said pattern,
(g) transferring said pattern through the barrier layer with a plasma etch,
(h) removing the photosensitive film with a stripping process, and transferring said pattern through the polyimide layer with a plasma etch, and
(i) stripping the barrier layer,
(j) wherein a develop time after said first exposure dose is less than required for a develop time with a single exposure method having a higher dose than said first exposure dose.
21. The method of claim 20 wherein said barrier layer is an organic, inorganic, or metal layer that has a high plasma etch selectivity to the cured polyimide layer.
22. The method of claim 20 wherein said barrier layer is silicon nitride or silicon oxynitride.
23. The method of claim 20 wherein said photosensitive film is a negative tone photosensitive comprised of a polyvinyl phenol, a crosslinkable component with acid labile groups, and a photoacid generator.
24. The method of claim 20 wherein the said first exposure is performed with a scanner or stepper using one or more wavelengths selected from a range of about 200 nm to about 600 nm and preferably 248 nm, 365 nm or 436 nm and wherein said second exposure dose is from a broad band exposure tool without alignment capability that can expose the entire substrate without scanning or stepping.
25. The method of claim 20 wherein said pattern in said polyimide layer is comprised of space widths or feature sizes smaller than 2 microns and preferably less than 1 micron.
26. The method of claim 20 wherein the photosensitive layer and barrier layer form a bilayer imaging scheme wherein the optical properties are matched such that the barrier layer also serves as an anti-reflective layer.
27. The method of claim 20 wherein said barrier layer is aluminum.
28. The method of claim 20 wherein the develop time after said first exposure dose is less than required for the develop time with a single exposure method having a higher dose than said first exposure dose.
29. The method as in claim 1, wherein said substrate comprises a polymide precursor film formed on a base substrate and further comprising, after said exposing said developed photosensitive,
(e) transferring the pattern through the polymide precursor layer with a wet etch,
(f) removing the photosensitive film with a stripping process, and
(g) curing the polymide precursor layer by baking to about 350\xb0 C. for about 1 hour to form a patterned polymide layer.
30. The method as in claim 1, wherein said substrate comprises a barrier layer formed on a polymide film formed on a base substrate and further comprising, after said exposing said developed photosensitive without a mask:
(e) transferring the pattern through the barrier layer with a plasma etch,
(f) removing the photosensitive film with a stripping process, and transferring said pattern through the polymide layer with a plasma etch, and
(g) stripping the barrier layer.
31. The method as in claim 1, wherein said coating comprises coating a negative tone photosensitive solution on a substrate and said baking comprises baking to form a negative tone photosensitive film.
32. A method of forming a pattern with improved structural strength in a negative tone photosensitive film comprising:
(a) coating a negative tone photosensitive solution on a substrate and baking to form a negative tone photosensitive film,
(b) exposing said substrate with a patterned mask and first exposure dose that does not completely crosslink the photosensitive film,
(c) developing said exposed photosensitive film in an aqueous base solution, and
(d) exposing said developed photosensitive film without a mask and a second exposure dose that is higher than first exposure dose to form a saturated crosslinked network,
(e) wherein a develop time after said first exposure dose is less than required for a develop time with a single exposure method having a higher dose than said first exposure dose.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An aqueous vulcanizable adhesive composition, which comprises a phenol resin emulsion prepared from a water-insoluble phenol resin solution in methyl ethyl ketone and an aqueous water-soluble polymeric substance solution, and a curing agent for phenol resin. resin, the content of methyl ethyl ketone being not more than 10 wt. %.
2. An aqueous vulcanizable adhesive composition according to claim 1, wherein the phenol resin emulsion comprises 5 to 25 wt. % of water-insoluble phenol resin, 0.2 to 6 wt. % of water-soluble polymeric substance, and 3 to 40% of methyl ethyl ketone, the balance being water.
3. (canceled)
4. An aqueous vulcanizable adhesive composition according to claim 1, wherein the water-insoluble phenol resin is a novolak type phenol resin or a mixture of a novolak type resin with a resol type phenol resin.
5. An aqueous vulcanizable adhesive composition according to claim 4, wherein not more than 200 parts by weight of the resol type phenol resin is used on the basis of 100 parts by weight of the novolak type phenol resin.
6. An aqueous vulcanizable adhesive composition according to claim 1, wherein the water-insoluble phenol resin is used as a solution at a concentration of 40 to 60 wt. % in methyl ethyl ketone.
7. An aqueous vulcanizable adhesive composition according to claim 1, wherein the water-soluble polymeric substance is polyvinyl alcohol.
8. An aqueous vulcanizable adhesive composition according to claim 1, wherein the water-soluble polymeric substance is acetoacetyl-modified polyvinyl alcohol.
9. An aqueous vulcanizable adhesive composition according to claim 8, wherein the phenol resin emulsion further includes an organometallic compound.
10. An aqueous vulcanizable adhesive composition according to claim 1, wherein the curing agent for phenol resin is hexamethylene-tetramine.
11. An aqueous vulcanizable adhesive composition according to claim 10, wherein 0.1 to 5 parts by weight of the hexamethylenetetramine is used on the basis of 100 parts by weight of the phenol resin emulsion.
12. An aqueous vulcanizable adhesive composition according to claim 10, wherein water is use together with hexamethylenetetramine.
13. An aqueous vulcanizable adhesive composition according to claim 12, wherein not more that 1,000 parts by weight of the water is used on the basis of 100 parts by weight of the phenol resin emulsion.
14. An aqueous vulcanizable adhesive composition according to claim 1, for used in vulcanization bonding of a metal or resin to rubber.
15. An aqueous vulcanizable adhesive composition according to claim 14, wherein the rubber is nitrile rubber, hydrogenated nitrile rubber or acrylic rubber.
16. A composite of rubber and metal or resin vulcanization bonded by an aqueous vulcanizable adhesive composition according to claim 1.
17. A phenol resin emulsion prepared from a water-insoluble phenol resin solution in methyl ethyl ketone and an aqueous water-soluble polymeric substance solution.