GB2540121A - Photosensitive film - Google Patents
Photosensitive film Download PDFInfo
- Publication number
- GB2540121A GB2540121A GB1509302.4A GB201509302A GB2540121A GB 2540121 A GB2540121 A GB 2540121A GB 201509302 A GB201509302 A GB 201509302A GB 2540121 A GB2540121 A GB 2540121A
- Authority
- GB
- United Kingdom
- Prior art keywords
- film
- coating
- volume
- layer
- pcb
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
- H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process
- H05K3/061—Etching masks
- H05K3/064—Photoresists
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/46—Polymerisation initiated by wave energy or particle radiation
- C08F2/48—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/016—Diazonium salts or compounds
- G03F7/0166—Diazonium salts or compounds characterised by the non-macromolecular additives
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/016—Diazonium salts or compounds
- G03F7/021—Macromolecular diazonium compounds; Macromolecular additives, e.g. binders
- G03F7/0212—Macromolecular diazonium compounds; Macromolecular additives, e.g. binders characterised by the polymeric binder or the macromolecular additives other than the diazo resins or the polymeric diazonium compounds
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/085—Photosensitive compositions characterised by adhesion-promoting non-macromolecular additives
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/0002—Apparatus or processes for manufacturing printed circuits for manufacturing artworks for printed circuits
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Laminated Bodies (AREA)
- Paints Or Removers (AREA)
Abstract
A film or coating for use in PCB production, the coating or film comprising a base layer and a coating layer comprising a co-binder to adhere the layers together. The binder comprises between 2% and 3% by volume of a low alcohol functional acrylic co-polymer in solution and a stabiliser comprising between 0.1% and 0.2% by volume a urea derivative (such as, for example N,N-dimethyl urea). The base layer may be polyester and the coating layer may be a photosensitive layer, which may contain diazonium as a component. The film may be for use in printed circuit board production and may comprise providing a base layer and a second coating layer, binding the first and second layers together using a co-binder, wherein the co-binder comprises between 2.3-2.7% by volume of a low alcohol functional acrylic co-polymer in solution and a stabiliser comprising 0.1-0.13% by volume of a urea derivative.
Description
PHOTOSENSITIVE FILM
Field of the Invention
This invention relates to photosensitive film, a co-binder for use in the manufacture of such film, and a manufacturing method thereof, inter alia for use in the creation of printed circuit boards (PCBs).
Background of the Invention
In the manufacture of PCBs, the process starts with a laminate comprising a dielectric substrate carrying a copper sheet on one or both sides. The copper sheet is overlaid with a phot-resistive layer. A photo-tool, typically a film carrying a negative image of the required electrically-conductive track pattern, is provided and laid over the photo-resist layer. Ultraviolet (UV) light is exposed to the laminate through the photo-tool; this causes the photo-resist layer exposed to the UV light to harden, thus creating a negative image of that on the photo-tool. The photo-resist and copper layers of the remaining, unexposed, areas are removed, e.g. using chemical etching, resulting in a PCB with the required copper circuity.
The photo-tool may be created from film taking different forms. Silver halide film is a well-known form, comprising a polyester base layer coated with an emulsion containing light-sensitive silver compounds that are exposed and developed to produce relatively permanent images. Silver halide film has high photo-sensitivity and so tends to be used by some for the PCB master. It is expensive, however.
An alternative film for creating a photo-tool is Diazo film, containing the light-sensitive diazo component. It has lower cost but disadvantages in terms of stability/durability, and life expectancy because it fades in direct proportion to its exposure to light. Diazo film tends not to be used for the master copy.
Summary of the Invention A first aspect of the invention provides a film or coating, inter alia suitable for use in PCB production, the coating or film comprising a base layer, a coating layer comprising a cobinder to adhere the layers together, said binder comprising between 2% and 3% by volume of a low alcohol functional acrylic co-polymer in solution and a stabiliser comprising between 0.1% and 0.2% by volume a urea derivative (such as, for example Ν,Ν-dimethyl urea).
Preferably the binder comprises between 2.3% and 2.7% by volume of a low alcohol functional acrylic co-polymer in solution.
Preferably still the stabiliser comprises between 0.10 and 0.13% by volume a urea derivative (such as, for example Ν,Ν-dimethyl urea).
The base layer may be a polyester (e.g. PET) layer. The coating layer may be a photo-sensitive layer. The coating layer may include diazonium as a component.
Preferably the co-binder content is 2% to 3% by volume. Preferably still the co-binder content is 2.56% by volume.
Preferably the stabiliser content is 0.1% to 0.2% by volume. Preferably still the stabiliser content is 0.12% by volume.
In another aspect, the invention provides a coating or film for inter alia use in PCB production printed which comprises by volume one or more of the following: between 70.0 and 75.0% of a solvent (preferably 72.470%); between 3 and 5.0% ethanol (preferably 4.263%); between 3.0 and 4.0% cellulose acetate propionate (preferably 3.417%); between 2.0 and 3.5% cellulose ester (preferably 2.981%); between 2.0 and 3.0% low OH functional acrylic co-polymer in solution (preferably 2.560%); between 0.05 and 0.20% of a solution of a silicone additive (preferably 0.147%); between 1.6 and 1.9% of a cross-linker (preferably 1.776%); between 0.10 and 1% of an acid-stabiliser (preferably 0.403%); between 0.05 and 0.20% of a stabiliser (preferably 0.120%); between 0.001 and 0.2% of a matting agent (preferably between 0.007 and 0.160%); between 1.00 and 3.00% of one or more couplers (preferably 1.102% of a first coupler and 0.385% of a second coupler); and between 1.5 and 2.0% of a diazonium salt (preferably 1.690%).
Another aspect provides a method of forming or manufacturing a PCB, the method comprising providing a film according to any above definition, the film carrying a track pattern, laying the film over a PCB, and exposing the PCB to a light source which passes through at least part of the film.
In another aspect, the invention provides a method of manufacturing film for use in PCB production, the method comprising: providing a first, base layer and a second, coating layer, and binding the first and second layers together using a co-binder, wherein the co-binder comprises between 2.3 and 2.7% by volume of a low alcohol functional acrylic co-polymer in solution and a stabiliser comprising between 0.10 and 0.13% by volume N,Ν'-dimethylurea.
In another aspect, the invention provides a method of manufacturing a coating or film for use in PCB production, the method comprising: providing a first, base layer and a second, coating layer, and binding the first and second layers together using a co-binder, wherein the co-binder comprises by volume one or more of the following: between 71.0 and 73.0 % of a solvent (preferably 72.470%); between 3.5 and 5.0% ethanol (preferably 4.263%); between 3.0 and 4.0% cellulose acetate propionate (preferably 3.417%); between 2.0 and 3.5% cellulose ester (preferably 2.981%); between 2.0 and 3.0% low OH functional acrylic co-polymer in solution (preferably 2.560%); between 0.05 and 0.20% of a solution of a silicone additive (preferably 0.147%); between 1.6 and 1.85% of a cross-linker (preferably 1.776%); between 0.10 and 0.80% of an acid-stabiliser (preferably 0.403%); between 0.05 and 0.20% of a stabiliser (preferably 0.120%); between 0.007 and 0.160% of a matting agent; between 1.00 and 3.00% of one or more couplers (preferably 1.102% of a first coupler and 0.385% of a second coupler); and between 1.5 and 2.0% of a diazonium salt (preferably 1.690%).
The above-mentioned solvent preferably comprises methyl ethyl ketone .
The solution of a silicone additive preferably comprises fumed or precipitated silica (for example, polyether modified polydimethylsiloxane).
The cross-linker preferably comprises butylated glycoluril.
The stabiliser preferably comprises N,Ν'-dimethylurea.
The acid stabiliser preferably comprises p-toluene sulfonic acid.
The matting agent preferably comprises finely ground silica.
In another aspect, the invention provides a binder or cobinder for binding or adhering layers together, comprising the above chemicals by volume, e.g. as defined in the first or subsequent definitions.
Detailed Description of Preferred Embodiments
As background, there are several products on the market for photosensitive films, all of which have the same chemical background which generally comprises a combination of solvents, cellulosic resins as main binder, an acid-stabilizer, a coupling-component, a diazo-component and a number of additives.
In the Applicant's view, all the products however have room for improvement, for example in terms of: • stronger adhesion of the coating-layer to the supporting Polyester base film; • lower and more stable values of UV-Dmin (the optical density (UV, 365nm) of transparent areas) of the film after imaging. An increase in UV-Dmin is caused by yellowing through UV-light, chemical reactions (degradation) by heat and humidity, or by chemical attack through the contact with the PCB's surface (solvent transfer); • increased levels and stability of UV-Dmax (the optical density (UV, 365nm) of the imaged areas). The azo-dye has to be as lightfast as possible or has to be protected by additives to prevent degradation through heat, humidity, or UV-light; • improved scratch-resistant surface; • increased dimensional-stability against climatic changes during processing and against mechanical stress; and • reduced stickiness of the surface. The PCB's surface shouldn't stick to the films surface. It's important, that no particles nor any volatile chemicals of the PCB's surface transfer or migrate to that of the film.
Applicant conducted extensive experimentation and tests to provide an improved film with enhanced properties.
Applicant focussed on seeking a co-binder which increased the adhesion of the coating-layer to a PET-base film. Applicant also sought co-binders which increased the surface hardness to improve scratch-resistance, whilst avoiding the coating-layer becoming brittle which would decrease the adhesion or cause the coating-layer to break and peel-off.
Applicant also focussed on seeking the right balance of a crosslinking agent (which is known to build elastic-films), and the ratio of two cellulosic resins.
The stability of UV-Dmin was investigated by a screening with antioxidants, salts of organic acids to build a pH-buffer-system inside the coating-layer and other known chemistry like Urea-derivates. Screening of the stabilizers found that two chemicals worked particularly well without negative influence to other parameters . A reduction in the stickiness of the surface was found by the addition of a silicone additive, normally used as a coating-additive to lower the surface tension of the wet-coating. The additive helped build layers of high clarity. A slight overdose of this group of additives helped to build release properties .
Thus, Applicant produced a film that comprised a base layer, a coating layer, and a co-binder to bind or adhere the layers together, said co-binder comprising between 2.3 and 2.7% by volume of an alcohol functional acrylic co-polymer in solution and a stabiliser comprising between 0.10 and 0.13% by volume a urea derivative (such as, for example Ν,Ν-dimethyl urea).
Applicant also produced a film that comprises by volume one or more of the following: between 71.0 and 73.0 % of a solvent (preferably 72.470%); between 3.5 and 5.0% ethanol (preferably 4.263%); between 3.0 and 4.0% cellulose acetate propionate (preferably 3.417%); between 2.0 and 3.5% cellulose ester (preferably 2.981%); between 2.0 and 3.0% low OH functional acrylic co-polymer in solution (preferably 2.560%); between 0.05 and 0.20% of a solution of a silicone additive (preferably 0.147%); between 1.6 and 1.85% of a cross-linker (preferably 1.776%); between 0.10 and 0.80% of an acid-stabiliser (preferably 0.403%); between 0.05 and 0.20% of a stabiliser (preferably 0.120%); between 0.007 and 0.160% of a matting agent; between 1.00 and 3.00% of one or more couplers (preferably 1.102% of a first coupler and 0.385% of a second coupler); and between 1.5 and 2.0% of a diazonium salt (preferably 1.690%).
Said films, were found to overcome or reduce disadvantages associated with conventional co-binders, and therefore film used in the PCB sector.
It will be appreciated that the foregoing is merely exemplary and that modifications can readily be made thereto without departing from the scope of the invention.
Claims (12)
1. A film or coating, inter alia suitable for use in PCB production, the coating or film comprising a base layer, a coating layer comprising a co-binder to adhere the layers together, said binder comprising between 2% and 3% by volume of a low alcohol functional acrylic co-polymer in solution and a stabiliser comprising between 0.1% and 0.2% by volume a urea derivative.
2. A film or coating according to claim 1 wherein the urea derivative is Ν,Ν-dimethyl urea.
3. A film or coating according to claim 1 or claim 2, wherein the binder comprises between 2.3% and 2.7% by volume of a low alcohol functional acrylic co-polymer in solution.
4. A film or coating according to any one of claims 1 to 3, wherein the base layer is a polyester layer.
5. A film or coating according to any one of claims 1 to 4, wherein the coating layer is a photo-sensitive layer.
6. A film or coating according to claim 5, wherein the coating layer may include diazonium as a component.
7. A coating or film for inter alia use in PCB production printed which comprises by volume one or more of the following: between 70.0 and 75.0% of a solvent; between 3 and 5.0% ethanol; between 3.0 and 4.0% cellulose acetate propionate; between 2.0 and 3.5% cellulose ester; between 2.0 and 3.0% low OH functional acrylic co-polymer in solution; between 0.05 and 0.20% of a solution of a silicone additive; between 1.6 and 1.9% of a crosslinker; between 0.10 and 1% of an acid-stabiliser; between 0.05 and 0.20% of a stabiliser; between 0.001 and 0.2% of a matting agent; between 1.00 and 3.00% of one or more couplers and between 1.5 and 2.0% of a diazonium salt.
8. A method of forming or manufacturing a PCB, the method comprising providing a film according to any preceding claim, the film carrying a track pattern, laying the film over a PCB, and exposing the PCB to a light source which passes through at least part of the film.
9. A method of manufacturing film for use in PCB production, the method comprising: providing a first base layer and a second coating layer, and binding the first and second layers together using a co-binder, wherein the co-binder comprises between 2.3 and 2.7% by volume of a low alcohol functional acrylic co-polymer in solution and a stabiliser comprising between 0.10 and 0.13% by volume a urea derivative.
10. A film or coating substantially as hereinbefore described.
11. A method of forming or manufacturing a PCB substantially as hereinbefore described.
12. A method of manufacturing film for use in PCB production substantially as hereinbefore described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1509302.4A GB2540121A (en) | 2015-05-29 | 2015-05-29 | Photosensitive film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1509302.4A GB2540121A (en) | 2015-05-29 | 2015-05-29 | Photosensitive film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201509302D0 GB201509302D0 (en) | 2015-07-15 |
| GB2540121A true GB2540121A (en) | 2017-01-11 |
Family
ID=53677450
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1509302.4A Withdrawn GB2540121A (en) | 2015-05-29 | 2015-05-29 | Photosensitive film |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2540121A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5497779A (en) * | 1978-01-19 | 1979-08-02 | Matsushita Electric Ind Co Ltd | Printed circuit board |
| US4473678A (en) * | 1981-11-27 | 1984-09-25 | Rohm Gmbh | Aqueous dispersion of a self-crosslinking resin |
| JPS60208484A (en) * | 1984-04-02 | 1985-10-21 | Dainippon Ink & Chem Inc | Etching resist ink |
-
2015
- 2015-05-29 GB GB1509302.4A patent/GB2540121A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5497779A (en) * | 1978-01-19 | 1979-08-02 | Matsushita Electric Ind Co Ltd | Printed circuit board |
| US4473678A (en) * | 1981-11-27 | 1984-09-25 | Rohm Gmbh | Aqueous dispersion of a self-crosslinking resin |
| JPS60208484A (en) * | 1984-04-02 | 1985-10-21 | Dainippon Ink & Chem Inc | Etching resist ink |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201509302D0 (en) | 2015-07-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |