PRECISION FLEXIBLE LOOP AND METHOD FOR HIGH DENSITY ASSEMBLY OF ELECTRONIC DEVICE USING SUCH LOOPS Russian patent published in 2007 - IPC H05K1/11 H05K3/30 H05K3/34 

FIELD: engineering of flexible multilayer electronic boards (loops) for assembly of microelectronic equipment.

SUBSTANCE: in accordance to the invention, as substrate material, polyimide, polyether and fluoroplastic films are used. Polyimide film substrates make it possible to achieve high thermal stability of loops and allow usage of different methods of assembly, including welding and soldering, and fluoroplastic films are most usable for making loops based on them for assembly of UHF circuits, due to low losses in UHF frequency range and possible constant wave resistance of loops which connect UHF modules and devices. Structure and placement of contact areas, meant for assembly of electronic components or connection of loop to other devices or electronic boards, and also materials and covers, used for forming aforementioned contact areas, must also provide for high density inter-cell connection in electronic equipment. To that end, contact areas are positioned on the other side of flexible substrate and connected to working conductors via through metallized apertures in the substrate. External sides of contact areas are tin-plated, for example, covered in layer of tin-bismuth alloy, onto the surface of contact areas which is adjacent to substrate, a layer of material is applied to prevent spreading of soldering alloy, chromium for example, and connection of contact areas of loop to contacts of electronic devices is realized by welding-soldering using double electrode tool for micro-mounting, brought to contact with the other surface of contact area via through aperture in the film positioned above the contact area.

EFFECT: manufacture of flexible electronic board, wherein the gap between adjacent conductors does not exceed 20 micrometers, making it possible to ensure placement density of components and contact areas for assembly thereof, approaching contact placement density of modern VLSI circuits.

2 cl, 2 tbl, 2 ex