IEC 61249-3-4:1999 pdf download.Materials for printed boards and other interconnecting structures
1 Scope
This part of IEC 61 249 gives requirements for flexible polyimide films coated on one side or both sides with acrylic or epoxide type adhesive for use in the fabrication of flexible printed wiring. Films coated on only one side are used as a coverlay or covercoat in the fabrication of flexible printed wiring. This coverlay or covercoat is also used to provide local support to areas subjected to mechanical or environmental stress. Films coated on both sides are used as bonding films in the fabrication of printed boards.
2 Normative reference
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of IEC 61 249. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of IEC 61 249 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of IEC and ISO maintain registers of currently valid International Standards.
IEC 61 1 89-2:1 997, Test methods for electrical materials, interconnection structures and
assemblies – Part 2: Test methods for materials for interconnection structures
3 Materials and construction
The material consists of an insulating flexible film base of polyimide coated with an adhesive
on one side or both sides.
3.1 Insulating film
Polyimide films of preferred thicknesses and permitted tolerances are given in table 1 when
measured by the method 2D01 of IEC 61 1 89-2, provided that the micrometer used is capable
of resolving 0,002 mm or better.
Other thicknesses may be used by agreement between purchaser and supplier. The maximum
permitted tolerances of such thicknesses shall be those of the nearest greater thickness stated
in table 1 .
6 6.1 Properties of adhesive coated polyimide films Appearance
The adhesive coated film shall be free from blisters and wrinkles. There shall be no imperfections which will be detrimental to the material properties or to their intended use. The film shall be uniform in colour and free from foreign inclusions. Colour degradation shall not occur when the film is processed in accordance with the manufacturer’s instructions. The adhesive shall be protected by a polymeric release film or release paper which shall adhere until lamination. For polyimide films with adhesive on both sides, one adhesive layer or both shall be protected with such release materials. The appearance of the adhesive coated film shall only be inspected with the release material present in cases where the release material is transparent. Where foreign inclusions appear to be imbedded in the adhesive and/or between the adhesive and the polyester film, the release material shall be removed and the coated film shall be re-inspected. 6.2 6.2.1 Properties of adhesive coated polyimide films after curing Preparation of laminated specimens In order to determine the properties listed in 6.2.2 and 6.2.3, laminated specimens shall be prepared as follows.
6.2.1.1 Specimens from cover sheets
Test specimens shall comply with the requirements of IEC 61 1 89-2 (see annex A). They shall be cut from a set of samples prepared by laminating copper foil to the film material under test. Laminating conditions should be agreed upon between purchaser and supplier, and should comply with the material manufacturer’s recommendations regarding pressure, temperature and pressing duration. The copper foil, as used in the fabrication of copper-clad laminates, shall have a thickness of 35 µm (305 g/m 2 ) and shall be applied with the untreated (shiny) side to the adhesive layer. If any argument arises in relation to the laminating conditions, it is desirable to apply the standard procedures and conditions in the relevant test method specification (see IEC 61 1 89-2) by agree- ment between purchaser and supplier. NOTE W hen the release or protective materials are peeled off from coverlay films with punched holes and/or slits for further fabrication processes, careful attention should be paid in order to avoid deformation of the film due to any excessive peeling force.
IEC 61249-3-4:1999 pdf download
