DD213556A1 - METHOD FOR STRUCTURING THICKNESS LAYER STRIPS BY MEANS OF LASER BEAM MACHINING - Google Patents

Abstract

The invention relates to the field of thick-film technology. The aim of the invention is to realize the finest interconnect structures. This should happen according to the object of the invention by a laser beam structuring. According to the invention, a first laser beam machining of the applied printed conductor material takes place first of all for fine structuring with an extremely narrow tolerance range of 85% d. practically necessary cutting power lying power of the beam. It is followed by a second laser beam processing, such that a laser beam is generated, d. a cutting performance that is practically necessary has a cutting capacity reduced to 40 to 50%. With this laser beam a maximum of 70% d. Distance of the material-removing boundaries made in the laser energy distribution curve of the first laser beam machining, so that a 30% reduced Abtragspurbreite is achieved. Within the process, the processed substrates are exposed to a defined ultrasonic action. The invention finds application in the finest conductor track structuring (conductor track width, conductor track distances less than 70 μm), in particular in the production of coils on ceramic carriers.

Description

in ι ι ι ι

Volker Seidel

Karl-Heinz Suphan

Hartmut Wottawa

Prof. Dr. Gerhard Zscherpe

Jürgen Henneberger

Georg Pfeil; j:

Achim Berger

Hans-Jürgen. L ebs rather ..:.

Title of the invention '-.' : ''^;

Process for structuring thick-film printed conductors by means of laser beam processing.

Field of application of the invention

The invention relates to the field of electronic technology. Its application is possible and expedient where thick-film conductors with small web widths and small spacings are to be structured relative to one another.

Characteristic of the known technical solutions

It is known to apply thick film conductors via screen printing processes, whereby conductor widths and conductor spacing of 200 μm are realized. Also known is a quasi-liturgical process, v / o with the help of the imprint of

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''i'odel'- Paste conductor distances of 80.' The resistance of the printed conductors is here however with 10 to 15 ml2 / θ too high for certain applications.A pressure with lietallmasken, dex is also well-known, leads however also It is also generally known to structure thick and thin film structures by means of laser beam processing (DD-PS 93 192), however, if one wishes to have stress patterns (cut-off track width or web width smaller than 70 μm) In the structuring of thick-film conductor tracks with the mentioned geometries, back and over-evaporation of the ablated material occurs in laser beam processing, in: the removal tracks the insulation resistance between the interconnects Ablative removal marks (at least 0.5 mm distance): be used ^ there the Rückdampfprozeß is negligible.

It is generally known to the person skilled in the art which cutting powers are necessary in order to pattern conductor tracks of conventional geometries and dimensions with specific removal track widths. It is primarily about achieving a complete removal of the material in the tracks.

the invention

The aim of the invention is to find a method for patterning of thick film conductor tracks using the laser beam machining, which ensures even in the manufacture finest structures a high insulation resistance (R. _S> Sl 10) between the individual structures. ,

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Explanation of the essence of the invention

The object of the invention is to provide a method for structuring thick-film conductor tracks by means of laser beam machining, which enables a 3-time structuring with little effort, without the back and overdamping of the removed material into the machining tracks being disadvantageous. According to the invention, a first laser beam machining of the printed conductor material applied to a substrate takes place firstly with an in a very narrow tolerance range for the fine structuring. 85 % of the practically necessary cutting power lying cutting power of the beam. It is followed by a second Iaserstrahlbearbeitung, such that a laser beam is generated, which has a cutting power practically necessary to a 40 to 50 % reduced cutting performance. With this laser beam, a maximum of 70 % of the distance of the material-removing boundaries in the laser energy distribution curve of the first laser beam machining is met, so that a 30 % reduced Abtragspurbreite is achieved. Within the process, the processed substrates are subjected to a defined ultrasound effect. In an embodiment of the invention, it is expedient that the second Läserstrahlbearbeitung consists of several cycles, the cutting performance from cycle to cycle remain the same or defined reduced * The invention is further designed so that the Ultraschallalleinwirkung during or after the second laser tr ahlbe processing he follows. It is expedient that the ultrasound action after the second laser beam machining takes place in the presence of a solvent, in which case methylene chloride is used in particular according to the invention.; ....: It is furthermore expedient to apply the entire strip material to be patterned. Screen printing has also proved to be a useful embodiment of the invention, with coarse-structured conductor track geometries being applied

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become. In screen printing, it has proven to be particularly effective if the printed circuit material is printed at a lower thickness where it is to be removed. It was surprising that when the laser beam machining with reduced cutting performance twice a Peijiststrukturierung of traces of thick film material is possible, the adverse effects of back and Überdampfpro-, _ be avoided processes''.'. · · ... '

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The invention will be explained below with reference to an embodiment.

The process according to the invention will be described on the basis of the production of finely structured coils which are deposited on ceramic carriers.

The coil structures, e.g. consist of gold, are either structured from a gold layer applied over the entire surface or coarse structured by screen printing and then finely textured according to the invention. For economic reasons, it proves to be particularly advantageous if the conductor material is printed with a certain profile j wherein the thickness of the printed conductor material is lower there, where the material is to be removed. '. , , '.' · '-'. ; ... the actual penalty structuring, i. The production of finest coil structures with ridge widths less than 70, Um and trace distances in the same area is now carried out according to the invention such that first a first laser beam machining is performed. The optical power of the beam is within a very narrow tolerance range of 85% of the practically necessary cutting performance for printed conductor Durcntrennungen. The edges of the processing track are melted, but already largely avoided return and 'tuberdungen. It is now necessary to remove these remaining in the processing track trace material particles. For this purpose, a laser beam is first generated, the one on 40th to

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50 % to the practically necessary cutting performance reduced Sehneidleistung has. A maximum of 70 % of the distance of the material-removing boundaries in the laser energy distribution curve of the first laser beam machining is hit with this laser beam, so that a cut-off track width reduced by 30 % is achieved.

This makes it possible to avoid re Bearbeitungssspurrandaufschmel-2ungen and loosen or to remove the material particles still in the track. The following table compares the parameters of the individual laser beam machining:

trim speed

Pulse repetition rate

-1 1

Laser power

cut

managerial

stung

normal ... Leadership 16

1. Laser beam machining 20

2. Ijaser jet machining 32

4 6

1.9

100;

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The remaining, relatively loose trace material remaining in the processing track, here e.g. Gold, is blasted off by ultrasound and appropriately eliminated. The ultrasonic effect takes place during the second laser beam processing or after this processing. Particularly good peeling effects can be achieved if the ultrasonic treatment is carried out after the second laser beam machining in a solvent bath, in particular in a methylene chloride bath. The following parameters of the ultrasonic bath are preferably used:

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US RF power: · 75 W ,

Frequency f: 40 kHz ^:

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After this process, finely structured printed circuit traces, in particular coils, have been produced, insulation resistances between the individual printed conductors being greater than 1.6. 10 li can be achieved. In order to "amplify the effect of the second laser beam processing, it is repeated several times using a laser beam of the same cutting power or reduced cutting power from cycle to cycle.

The method according to the invention makes possible a fine structuring of thick-layer printed circuit boards with dimensions, as mentioned in the characteristics of the known technical solutions. The number of screen prints required and the number of burn-in processes can thereby be considerably reduced. Due to the miniaturization of the structures, conductor material is saved. ... , To reduce the method according to the invention in the direction of improving the insulation resistance, an insulation paste can be printed via the removal track or over the entire structure. :. -. '' .-.

Claims (11)

^: ,: ' - 7 - '. P Inform ation P rue h. : -.-. .. : . '· ".. ·' 1. A method for otrukturierung of thick-film conductors by means of Laserstrahlbearbeittingy characterized in that the Peinststrukturierung a ^; first laser beam machining of the printed circuit material applied to a substrate with a very narrow tolerance range of 85 % of the practically necessary sneezing power of the beam, followed by a second laser beam machining, such that a reader beam is generated, which is a practically necessary Denden SehneidIeistung to 40 to 50 % reduced cutting performance has that this laser beam is directed only to a maximum of 70 % of the distance of the material-removing boundaries in the laser energy distribution curve of the first laser beam processing that with this laser beam a 30 % reduced width of the first track is removed and that the processed substrate is subjected to a defined ultrasonic action within the method. 2. The method according to item 1, ' characterized in that '..,, ..' '^: '. , , '· .. · ·\ '. , · ' the second 'laser beam machining of several : Working-cum-cykes composed. '.... 3. \ '"method according to item 2, characterized in that the' laser beam 'in, each cycle the same cutting performance '' '. having. ". ' . '..- .. .., .. · .. 4. The method according to item 2, characterized in that the cutting performance of the Tjaserstrahies defined cycle by cycle is reduced.     - 8th - . ; p 93? 5. The method according to item 1, characterized in that the ultrasound action takes place during the second laser beam machining *. / 6. The method according to item 1, characterized in that the ultrasound action takes place after the second laser beam processing. , 7. The method according to item 6, characterized by ,, that the ultrasonic action takes place in the presence of a solvent. " , 8. The method according to item 7, characterized in that βίε solvent methylene chloride is used. 9. The method according to item 1, characterized in that the conductor material to be structured is applied over the entire surface ". '. '' .. ·.; ' 10. The method according to item -1, characterized in that the. to be structured interconnect material. 1 is applied by screen printing coarse textured. ^: V 11. The method according to the points 9 and 10, characterized in that -the to be structured Ijeiterbahnmaterial. The entire surface is screen-printed, wherein the thickness of the conductor material is lower where it is to be removed. , 'V; -.'