SU970737A1 - Method of manufacturing multilayer printed circuit boards - Google Patents

Description

The invention relates to electronics, in particular, to the production of multilayer printed circuit boards.

• A known method of manufacturing multilayer boards on 5 dielectric substrates, according to which the switching layers are formed by etching copper in a metal layer deposited on a dielectric substrate [1]. ' ^υ

However, the use of subtractive technology for producing switching layers leads to irrationally high consumption of metals such as copper.

A known method of manufacturing multilayer printed circuit boards, which includes the formation of switching layers with contact pads for interlayer transitions on technological metal __ substrates by depositing metal through a mask from a photoresist, removing the photoresist, sequentially pressing a pair of switching layers through dielectric adhesive pads, mechanical peeling 25 technological metal substrates and the formation of metallized interlayer holes [2].

This method solves the issue of saving copper, however, the formation of through 30 metallized holes does not allow to obtain a high switching wiring density due to the fact that the diameter of the interlayer holes should increase with increasing thickness of the packet to ensure reliable metallization of the hole walls. In addition, during mechanical peeling of the technological metal substrate after pressing the switching layers, due to the different adhesive ability of the surface of the switching conductors and the dielectric adhesive strip, these elements are unevenly peeled, which leads to a decrease in the quality of the boards.

The purpose of the invention is to increase the density of switching and quality boards.

This goal is achieved by the fact that in a method of manufacturing multilayer boards, including the formation of switching layers with contact pads for interlayer transitions on technological metal substrates by depositing metal through a mask from a photoresist, removing the photoresist, ·· sequentially pressing a pair of switching layers through dielectric adhesive pads, mechanical detachment of technological metal substrates and the formation of interlayer holes, before the formation of layers of switching on technological When the formation of the switching layers in 5 contact pads for interlayer transitions, windows are opened, the interlayer holes are formed after mechanical peeling of the technological metal substrates from each pair of 1Q pressed switching layers by etching dielectric adhesive pads in the contact windows sites, and after the formation of interlayer holes, the intermediate layer of metal 15 уда is removed.

In FIG. 1-5 shows the sequence of basic technological operations of manufacturing multilayer printed circuit boards of the proposed method,

In the process of the substrate 1 made of stainless steel 0.25-1 mm thick is applied by electrochemical deposition in a sulfuric acid copper plating bath thin intermediate layer 2 is copper toLtsinoy __ 2-5 microns which is laminated plenoch · ^ ny photoresist ³ SMA 3 2 40 60 microns thick (Fig. 11

Using the photochemical method, wire patterns are formed in the photoresist, after which electrochemical deposition of copper in the copper sulphate copper bath produces contact pads 4 through passages and contact pads 5 for interlayer transitions with windows 6 (Fig. 2), as well as Fig. 35 conductors on other technological substrates.

Using the dielectric adhesive pad 7 (fiberglass SPT-3-0.025), the inner layers of the bag with conductors 8 and 9 are pressed together _(the technological substrates are removed by mechanical peeling and a thin copper layer is removed.

Next, using dielectric adhesive pads 10 (SPT-3-0.025) ^{4, they are} pressed onto the obtained structure. Layers with contact pads 5 on technological substrates 1 remove technological substrates (Fig. 3). After that, the method 11 opens the windows 11 in a thin layer of copper in the places of the interlayer transitions and etches the dielectric adhesive pads in the windows of the contact pads (Fig. 4), obtaining 55 interlayer holes 12. The holes are metallized by chemical and electrochemical copper plating, obtaining interlayer transitions 13, after which a thin layer of copper is removed from the whitespace 60 of the outer layers (Fig. 5).

In a similar manner, the layer-wise increase of layers of the printed circuit board switching is performed up to a given number of layers.

To implement the proposed technological process, equipment used in the production of standard printed circuit boards is used. In addition, specialized equipment has been introduced for combining the patterns of conductors on technological metal substrates and pressing layers on technological metal substrates.

The modes of technological processes, namely, chemical and electrochemical deposition of copper, etching of a dielectric correspond to standard technological processes OST 4.GO.054.223.

Using the proposed method allows to obtain high-quality multilayer boards with high switching density.

Claims (2)

metal substrates and the formation of interlayer holes, before the formation of switching layers on the technological metal substrates, an intermediate metal layer is applied; when forming the switching layers in the contact areas for interlayer transitions, the windows are opened, the interlayer holes are formed after the mechanical detachment of the technological metal substrates from each pair of pressed layers Commutation by etching dielectric adhesive pads in the windows of the contact pads, and after forming inters The luar holes of the intermediate metal layer are removed. FIG. 1-5 shows the sequence of the main technological operations for the manufacture of multilayer printed circuit boards by the proposed method. On technological substrates 1 of stainless steel with a thickness of 0.25-1 Mm, a thin intermediate layer 2 of copper of 2-5 microns is deposited by electrochemical deposition in a copper sulfate bath. which overlay the foamed photoresist 3 of SPF-2 with a thickness of 40– 60 μm (Fig. IX), in the photoresist, patterns of conductors are formed, after which, by electrochemical deposition of copper in copper sulfate, contact pads of through transitions and contact pads 5 for interlayer transitions with windows (Fig. 2), as well as drawings of conductors on other technological substrates. Using a dielectric adhesive strip 7 (glass fiber SPT-3-0.025), the inner layers of the package with conductors are pressed and 9) the technological substrates are removed by mechanical peeling and the thin layer of copper is removed. Next, using dielectric adhesive pads 10 (C11T-3-0.02, they are pressed to the structure obtained. Layers with contact pads 5 on technological substrates 1 and technological substrates are removed (Fig. 3). After this, the windows 11 in thin a layer of copper in the places of interlayer transitions and dielectric diets; adhesive pads in the windows of contact pads (Fig. 4), producing interlayer openings 12. Chemical and electrochemical copper plating metallize the openings, obtaining interlayer transitions 13, after which A thin layer of copper is removed from the gap spaces of the outer layers (Fig. 5). Similarly, the accumulation of the commutation commutation layers of the printed circuit board to a predetermined number of layers is carried out in a similar way. The equipment used in the production of standard printed circuit boards is used to perform the proposed technological process. . In addition, specialized equipment was introduced to align the patterns of conductors on technological metal substrates and to press the layers on technological metal substrates. The modes of technological processes, namely, chemical and electrochemical deposition of copper, etching of the dielectric correspond to typical technological processes OST 4.GO.054.223. Using the proposed method allows to obtain high-quality multilayer boards with high switching density. Claims The method of manufacturing multilayer printed circuit boards, including the formation of switching layers with contact pads for interlayer transitions on technological metal plates by depositing metal through a photoresist mask, removing a photoresist, sequentially pressing a pair of switching layers through dielectric adhesive pads, mechanically peeling off technological metal substrates and the formation of interlayer openings, about t l. due to the fact that, in order to increase the density of The switching and quality of the boards, before forming the layers, switching on the technological metal substrates, put an intermediate metal layer. When forming the switching layers in the contact pads for interlayer transitions, the windows are opened, the interlayer holes are formed after mechanical detachment of the technological metal substrates from each pair of pressed layers of switching by etching dielectric adhesive pads in the windows of the contact pads, and after forming the interlayer openings the intermediate layer the metal is removed. Sources of information taken into account in the examination 1. Hanki HGI., Fabian X. Technologists of the production of electronic equipment. Ed. VN Chernova ev., M., Energie, 1980, p. 158-168. 2. The patent of Japan 54-35670, cl. 59 G 4.05.11.79 (prototype). 12 fig.