EP1393603A1

EP1393603A1 - Method and device for structuring printed circuit boards

Info

Publication number: EP1393603A1
Application number: EP02740352A
Authority: EP
Inventors: Hubert De Steur; Marcel Heerman; Eddy Roelants
Original assignee: Siemens AG
Current assignee: Via Mechanics Ltd
Priority date: 2001-06-06
Filing date: 2002-05-15
Publication date: 2004-03-03
Also published as: DE10127357C1; US6783688B2; KR20040014547A; US20030000916A1; JP2004527923A; TW520625B; WO2002100137A1; CN1513285A

Abstract

The invention relates to a method in which both regions (3) of a printed circuit board (1), which are provided for rough conductor structures (31), as well as regions, which are provided for finer conductor structures (41) of the printed circuit board (1), are each structured by means of laser machining. To this end both regions (3, 4) are firstly coated with a continuous metallization layer and covered with an etch resist. The rough conductor structures are predefined using a laser beam (14) of a larger wavelength by exposing the unnecessary metal surfaces. In addition, the fine conductor structures are pre-formed by machining the etch resist with a laser beam (24) of a smaller wavelength. In a shared etching process, all exposed surface regions of the metal layer are subsequently etched away so that only the rough and fine conductor track structures covered by the remaining etch resist remain. The surfaces of the produced conductor tracks are exposed by removing the remaining etch resist.

Description

description

^¬ th Method and apparatus for structuring printed

The invention relates to a method and a device for patterning of printed circuit boards having coarse conductor structures and with at least one area with fine conductor ^¬ structures, deposited on an electrically insulating substrate, a metal layer and is exposed from this metal layer by partially etching the desired conductor pattern.

EP 0 062 300 A2 already discloses a method for producing printed circuit boards, in which a metallic etch resist applied to the entire surface of a metal layer is selectively removed again in the areas not corresponding to the conductor structures by means of laser radiation and then the conductor structures are etched off in such a way exposed metal layer are formed.

From DE 41 31 065 A1, a method for producing printed circuit boards is also known, in which a metal layer and a metallic or organic etching resist layer are applied in succession to a substrate, whereupon this etching resist layer is removed by means of laser radiation in the areas immediately adjacent to the later conductor track pattern and the metal layer thus exposed is etched away in such a way that the conductor track pattern and island regions of the metal layer electrically isolated therefrom by etching trenches remain on the substrate. The structuring by means of laser radiation can be carried out quickly since the areas of the etching resist layer to be removed need only have a small width and the larger areas remain between two conductor tracks. In WO 00/04750 Al is also a process for the manufacture ^¬ development of coarse conductor structures and fine conductor structures described, an etching resist is patterned by photolithography in which, in the region of the coarse conductor structures currency rend in the region of the fine conductor structures an etching resist using a Laser beam is structured. The etch resist layers structured in this way in different ways are then etched in a known manner. Although there is the possibility of working with the same tzresist for the different structuring processes and etching both the coarse and the fine conductor structures in one operation, this does not result in an optimal workflow, since the metallic etching resist usually used for laser structuring ( for example tin) is less suitable for the photolithography process.

The aim of the present invention is to provide a method and a device with which printed circuit boards with coarse and fine conductor structures can be structured in the simplest and most economical manner. According to the invention, this goal is achieved with the following process steps:

a) a metal layer is applied to an electrically insulating substrate, b) an etching resist layer is applied to the metal layer, c) by partially removing the etching resist layer (61) with a first laser beam (14) of a predetermined first wavelength and one through a first imaging unit

(13) predetermined first machining field size (3), the contours (62) of the coarse conductor structures (31) provided are exposed, d) by partially removing the etching resist layer (61) with a second laser beam (24) of a predetermined second

Wavelength and a second processing field size (4) predetermined by a second imaging unit (23) the contours (63) of the fine conductor structures freige ^¬ sets, wherein the second wavelength is less than the he ^¬ ste wavelength and / or the second field size (4) is smaller than the first field size (3), e) by etching the exposed metal areas (62,67), the coarse and the fine conductor structures (31,41) are generated simultaneously and momentarily ^¬ f) by removing the remaining resist layer to expose the surfaces of the conductor structures.

The invention therefore relates to producing both coarse and fine conductor structures using the same method steps, namely by structuring an etching resist layer and subsequent etching, but by taking into account the choice of different lasers to take account of the different conductor structures and correspondingly different insulation distances, and thereby for the respective structure to achieve the optimal processing speed. The invention makes use of the knowledge that a laser beam with a short wavelength and a short focal length can produce fine structures precisely in a small processing field, but is too slow for the processing of wider structures and larger fields for economical operation, while a laser beam with a long wavelength and a setting for a large focal length can process wider structures in a large processing field at a considerably higher speed. In an advantageous embodiment of the method according to the invention, it is provided that for processing the rough conductor structures, the first laser has a wavelength between 1064 nm and 355 nm, preferably 1064 nm, and the second laser has a wavelength between 532 and 266 nm, preferably 532 or 355 nm, the wavelength of the first laser being in any case greater than that of the second laser. Furthermore, it is provided in the preferred embodiment of the method according to the invention that the beam of the first laser is focused over a larger focal length than the beam of the second laser, whereby the first laser covers a larger processing area than the second.

A device according to the invention for the structuring of the managerial plates with a size coarse conductor structures and with at least ei ^¬ nem area with fine conductor structures has the following shopping ^¬ male to: a) a receptacle for positioning a printed circuit board, b) a first laser having a deflecting optical system and a Abbil- unit with a first focal length that is above the

PCB surface can be positioned such that it is able to irradiate a first processing field size, c) a second laser with deflection optics and an imaging unit with a second focal length, which can irradiate a second processing field size, the second laser having a greater wavelength than the first laser and / or the second focal length and the second field size are smaller than the first focal length and the first field size, and d) a control device to use the first laser to produce large fields of the circuit board with coarse conductor structures and smaller fields of the circuit board with the second laser to irradiate finer conductor structures.

The invention is explained in more detail below using exemplary embodiments with reference to the drawing.

It shows

FIG. 1 shows the schematic arrangement of two lasers for the method according to the invention,

2 shows a plan view of a schematically illustrated printed circuit board with coarse and fine conductor structures, FIGS. 3 to 6 show a section of a printed circuit board - in a sectional view - in the individual process stages in the production of the coarse and fine conductor structures according to the invention, Figure 7 is a plan view of the wiring pattern according Fi gur ^¬ 6,

FIG. 8 shows a diagram to illustrate the isolation trenches that can be achieved with different lasers depending on different layer thicknesses and different field sizes between the conductor structures and the achievable processing speeds.

An arrangement is shown schematically in FIG. 1 as is suitable for carrying out the method according to the invention. Two lasers, namely a first laser 11 and a second laser 21, are arranged above a printed circuit board 1, which lies in a processing area on a table 10 which can be moved in its plane in the x and y directions. The first laser 11 generates a first laser beam 14 via deflection optics 12 and a lens arrangement 13, which is focused on the surface of the printed circuit board 1 and can sweep over a first, relatively large processing field 3 due to a relatively large first focal length. The second laser 21 generates a second laser beam 24 via its deflecting optics 22 and the lens arrangement 23, which due to the smaller focal length 25 is able to sweep over a smaller processing field 4. Both lasers 11 and 21 have a different wavelength. For example, the laser 11 is a neodymium YAG laser with a wavelength of 1024 nm, while the laser 21 can be a neodymium vanadate laser with a wavelength of 532 or 355 nm. Both the two lasers 11 and 21 and the table are controlled by a central control unit 9.

FIG. 2 schematically shows a large machining field 3 with coarse conductor track structures 31 and a small machining field 4 with fine conductor structures 41 arranged within the machining field 3. According to the invention, both the coarse structures 31 and the fine structures 41 are created with the aid of the two lasers 11 and 21 method according to the invention obtained. CO co> N3 P ¹ P ¹ I o Cn O Cπ o Cn

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Claims

claims

1. A method for patterning of printed circuit boards (1) having coarse conductor structures (31) and with at least one region (4) having fine conductor structures (41) comprising the steps: a) on an electrically insulating substrate (7) is a Me ^¬ tallschicht ( 6) applied, b) an etching resist layer (61) is applied to the metal layer (6), c) by partially removing the etching resist layer (61) with a first laser beam (14) of a predetermined first wavelength and one through a first imaging unit (13) Given the first machining field size (3), the contours (62) of the coarse conductor structures (31) provided are exposed, d) by partially removing the etching resist layer (61) with a second laser beam (24) with a predetermined second wavelength and with a second imaging unit

(23) given the second machining field size (4), the contours (63) of the fine conductor structures are exposed, the second wavelength being smaller than the first wavelength and / or the second field size (4) being smaller than the first field size ( 3), e) the coarse and fine conductor structures (31, 41) are produced simultaneously by etching the exposed metal regions (62, 67) and f) the surfaces of the conductor structures (31, 41) are removed by removing the remaining etching resist layer (61) exposed.

2. The method according to claim 1, characterized in that the laser beam (14) of the first laser (11) has a wavelength between 1064 nm and 355 nm and the laser beam (24) of the second laser (21) has a wavelength between 532 nm and 266 nm - Points, whereby - the wavelength of the second laser beam (24) is equal to or less than that of the first laser beam (14) in any case.

3. The method according to claim 2, characterized in that the first laser beam has a wavelength of 1064 nm and the second La ^¬ serstrahl having a wavelength of 532 or 355 nm.

4. The method according to any one of claims 1 to 3, characterized in that the first laser (11) has an optical imaging unit (13) which has a larger focal length (15) than the optical imaging unit (23) of the second laser (12th ).

5. Device for structuring printed circuit boards (1) with coarse conductor structures (31) and with at least one area

(4) with fine conductor structures (41), which has the following features: a) a receptacle (10) for positioning a circuit board

(1), b) a first laser (11) with a deflecting optics (12) and an imaging unit (13) with a first focal length (15) which can be positioned above the circuit board surface in such a way that it irradiates a first processing field size (3) is able, c) a second laser (21) with a deflection optics (22) and an imaging unit (23) with such a second focal length (25) that the laser can irradiate a second processing field size (4), the second laser (11) has a smaller wavelength than the first laser (12) and / or wherein the second focal length (25) and the second field size (4) are smaller than the first focal length (15) and the first field size (3), and d ) a control device (9) to use the first laser

(11) large fields (3) of the circuit board (1) with coarse conductor structures (31) and with the second laser

(12) to irradiate smaller fields (4) of the printed circuit board with finer conductor structures (41).

6. Device according to claim 5, characterized in that the first laser has a wavelength between 1064 nm and 355 nm and the second laser (12) has a wavelength between 532 and 266 nm, that the first field size between 150 x 150 mm ² and 50 x Is 80 mm ² and the second field size is between 100 x 100 mm ² and 25 x 25 mm ² .