Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Patent
1997-07-23
1999-09-21
Turner, Archene
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
20419225, 20419229, 20419235, 20429831, 296 841, 338 34, 338 35, 427110, 4271261, 4271262, 4271263, 427162, 427165, 427168, 427343, 428195, 428336, 428432, 428446, 428697, 428699, 428701, 428702, B23K 2600, H05K 302
Patent
active
059551798
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a coating for the structured production of conductors on the surface of electrically insulating substrates, especially for the manufacture of sensor elements and printed circuit boards, wherein the coating is formed by a doped tin oxide layer with the composition Sn.sub.1-(y+z) A.sub.y B.sub.z O.sub.2 with A=Sb or F and B=In or Al, and to a method for applying the coating.
In chip and wafer production for microsensors, for hybrid circuits, displays, etc., the structured production of conductors plays a central role. In these areas so-called "masters," (masks) are used for the structuring, which as a rule consist of glass material as the support. On this material a thin, homogeneous or inhomogeneous layer, of chromium as a rule, is vapor deposited, which then must be structured with the required layout. Also in many other areas of electronics, the structuring of thin coatings or sandwiches on chiefly glass substrates is of interest with an view to their use as conductors and wiring systems. It is already known to coat a thin metal layer about 0.1 .mu.m to 0.2 .mu.m thick with a varnish, which is then exposed to an electron beam or laser beam or through optical systems and developed. Then a chemical etching step follows which removes the exposed metal surfaces.
In the field of printed circuit board manufacture, DE 40 10 244 A1 has disclosed the application of a conductive varnish to a circuit board and then working out the conductor pattern from the conductive varnish with aid of a laser. The thus produced conductor pattern is subsequently metallized.
DE 39 22 478 has already disclosed structuring plastic coated, copper-laminated base material with an excimer laser, i.e., removing the plastic coating in the areas where the conductive paths are thereafter applied by electrolytic deposition of metal. Furthermore, in this semi-additive process an alternative is envisioned of after deposition of the metal, removing the copper layer remaining between the conductor paths with the excimer laser instead of by chemical etching. For this purpose, however, an unrealistically high energy density is required, among other things. For this reason alone this process is unsuitable for economical fine structuring.
The use of full-surface tin oxide coatings for thin-layer heating elements has been disclosed by EP 0 280 362 B1. A two-fold doping of tin oxide with antimony and indium is also described therein, which is said to make it possible to use such coatings in thin-layer heating elements at elevated temperatures. It is known that tin oxide coatings interact with the atmosphere (O.sub.2, H.sub.2 O), especially at high temperatures, which can lead to considerable variations in their electric conductivity. To be able to use such coatings as electrically stable, transparent thin-layer heating elements even at high temperatures, antimony and indium are doped equimolarly, i.e., in the same amount. It is especially pointed out that these amounts must not differ from one another by more than 10%. The coatings furthermore have an antimony and indium content of 4.5 mol-% each. The antimony thereby increases the conductivity, and the indium stabilizes the crystal defects.
It is the object of the invention to provide a thin and electrically conductive coating that can be applied to glass or ceramic substrates and in which insulating channels can be directly structured with high resolution and without residue.
Because the proportion of antimony or fluorine dopants to indium or aluminum in the coating is defined by the limits 0.02<y+z<0.11 and the ratio of the dopants satisfies the condition 1.4<y/z<2.2, it is surprisingly achieved that such coatings are structurable with insulating channels with high resolution and freedom from residue by ablation by means of electromagnetic laser radiation in the wavelength range of 157 nm to 308 nm. It has furthermore been found that laser radiation in the infrared wavelength range up to 1064 nm can be used for the high-resolution structuring of the coating accor
REFERENCES:
patent: 4066815 (1978-01-01), Olink et al.
patent: 4859496 (1989-08-01), Toyonaga et al.
patent: 4889974 (1989-12-01), Auding et al.
patent: 4900634 (1990-02-01), Terneu et al.
patent: 5397920 (1995-03-01), Tran
Kickelhain Joerg
Vitt Bruno
LPKF Laser & Electronics AG
Turner Archene
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