Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Forming nonplanar surface
Reexamination Certificate
1998-01-30
2001-10-16
Young, Christopher G. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Forming nonplanar surface
C430S315000, C430S326000
Reexamination Certificate
active
06303278
ABSTRACT:
The present invention relates to a new method for modifying surfaces in an organic material, especially a polymeric material. The method is especially related to modifying non conducting surfaces to facilitate the arrangement of conducting material in distinct patterns on said surfaces. The present invention also comprises methods to produce products with conducting materials in distinct patterns as well as products produced by means of one of these methods.
BACKGROUND OF THE INVENTION
In many different technical fields there is a need to arrange thin layers of a conducting material on a non conducting substrate. In the manufacturing of electronic components this need is evident. Circuit boards are an example of products, where materials with different conducting properties are required to be combined with a large precision and a high resolution. Nowadays ever increasing demands are put on both the production processes and the products. The methods mainly used nowadays to produce circuit boards are subtractive. This implies that one starts from a substrate provided with a conductor, from which substrate the conducting material is removed in several successive steps from the surfaces where an electric conducting capacity is not desirable.
In traditional manufacturing of circuit boards one starts from a substrate or a basic laminate, in which a hole picture is drilled to allow the application components and/or connection of conducting layers on opposite sides of the substrate. On the substrate is thereafter deposited a conducting material in the holes, usually copper. Then, a thin light sensitive film is applied over the substrate, often under high pressure and high temperature. On this film a photographing tool is placed in form of a negative picture of the desired circuit pattern, the photographing tool then being exposed to UV-light, the film thereby polymerizing in the exposed areas. The exposed, light sensitive film is developed and the non polymerized areas are washed off by means of a suitable base. The desired circuit pattern is thus enclosed by the remaining film. Then, a metal e.g. copper is electrolytically plated, according to this pattern. Over this pattern tin or lead is plated, whereafter the film is removed in a bath, e.g. by means of a strong base. Thereafter, the layer of tin or lead is etched off, whereafter a liquid soldering masque is applied, e.g. in form of an epoxy color with two components. The soldering masque is exposed and developed and finally a protective layer in nickel or gold is applied to prevent any oxidation.
This method involves several drawbacks. Firstly the production process is very labor intensive leading to that the production of circuit boards is to a large extent being transferred to countries with low labor costs. Secondly large quantities of residues harmful to the environment are formed, mainly in the form of etching fluids with high metal contents, e.g. copper, lead, tin, etc. Thirdly the existing production methods do not comply with the increasing technical demands. The conventional methods are approaching their inherent limits, especially regarding the line width.
Thus, there is an apparent demand to simplify the production processes, to increase the automatisation level and to simultaneously remove the environmental problems connected with the present use of reactive chemicals and metals in solution. Simultaneously a lot of research and development efforts are aiming at making both electronic components and circuit boards less material and space consuming. The production of circuit boards is here below presented as an example for one of the many applications, for which the present invention is applicable.
STATE OF THE ART
It is already known to modify polymeric surfaces to increase the adhesive capacity between them. For example Wan-Tai Yang e.g. describes in his doctor's dissertation ‘Lamination by photografting’(KTH, Institute for Polymer Technology) how thin polymeric layers can be joined together by using photoinitiators and a irradiation with UV-light. The advantage with photolamination is that the method consumes little energy, does not create any waste to be discharged, involves short hardening periods and provides excellent product features, such as lack of shrinkage and the avoidance of enclosed solvents.
U.S. Pat. No. 4,006,269 describes a method to make the surface of a substrate in a non conducting material more sensitive using a substance which photochemically removes a hydrogen atom from a proton donator in the presence of a suitable solvent and provides a ketyl radial, whereafter the substrate is submerged in a platina solution comprising metal ions. Thereafter, the substrate is irradiated being submerged in the platina solution with an UV-irradiation within the interval between 200 and 400 &mgr;m to provide said ketyl radical reducing metal ions to metal. As suitable sensitizing compounds are named benzophenone, mono- or di-para-substituted halogen, methyl-, methoxi- and sulphonate-benzophenone. As a proton donator a secondary alcohol is used, e.g. benzoehydrole. As an example of solvents is named isopropylalcohol, ethylene glycol and polyethylene glycol. As an example of plating metals are named nickel and copper.
SHORT DESCRIPTION OF THE INVENTION
The present invention relates to a new method for modifying surfaces according to the attached claims. The invention especially concerns a new method to arrange conducting materials in distinct patterns on a substrate of a polymeric material or a substrate containing at least one surface with a surface layer of an organic material according to the attached claims.
REFERENCES:
patent: 5225495 (1993-07-01), Han et al.
patent: 5919402 (1999-07-01), Murhphy et al.
patent: 0187706A2 (1986-07-01), None
patent: 0309684A1 (1989-04-01), None
patent: 0487857A2 (1992-06-01), None
patent: 2346743 (1977-10-01), None
IBM Technical Disclosure Bulletin, vol. 30, No. 6, Anonym, “Method of improving metal adhesion to polymide”, p. 414, Nov. 1987.
WPI/Derwent's abstract, No. 85-253684, week 8522, Abstract of JP, 60169186, Sep. 2, 1985.
WPI/Derwent's abstract, No. 80-57740C, week 8025, Abstract of JP, 55086744, Jun. 30, 1980.
Forsling Willis Rudolf
Gunneriusson Lars Anders
Hedlund Stig Tomas
Larsson Karl-Gunnar
Lindberg Mats Einar Eugen
Birch & Stewart Kolasch & Birch, LLP
Cuptronic AB
Young Christopher G.
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