RU2778285C1 - Method for manufacturing the structure of an optoelectronic bus of a printed circuit board and apparatus for implementation thereof - Google Patents

Abstract

FIELD: electronics.

SUBSTANCE: invention relates to the technology for manufacturing a printed circuit board and/or a substrate of the body of a semiconductor integrated circuit, in particular, to a method for manufacturing the structure of a high-density optical waveguide and to the printed circuit board itself. Claimed method for manufacturing the structure of an optoelectronic bus on the surface of a printed circuit board consists in manufacturing a master die of the structure of optical waveguides of an optoelectronic bus, applying a polymer material of the of optical waveguides, applying a polymer material of the lower shell of optical waveguides, and applying a polymer material of the upper shell of optical waveguides. The method of photolithography is therein used in order to produce the master die, consecutively applying the two layers thereof and forming a two-layer structure of the master die from a single material, then applying a layer of an adhesion modifier to the formed master die structure. The polymer material of the core of optical waveguides is then applied to the master die by pouring, followed by broaching with a scraper over the master die, the polymer material of the lower shell is applied, followed by broaching with a scraper over a frame of a set thickness, and the polymer material of the lower shell is covered with the base of the printed circuit board with a preactivated contact surface and held until the polymer materials are fully cured. The base, being a printed circuit board with the formed layers of the lower shell and the core of optical waveguides, is then removed from the master die, followed by applying the polymer material of the upper shell and subsequently broaching over a frame of a set thickness. The apparatus of an optoelectronic bus of a printed circuit board comprises a base of a printed circuit board with the above structures of polymer planar optical waveguides of the optoelectronic bus applied thereon. The cross section of cores of the polymer planar optical waveguides is therein rectangular with the dimensions of the rectangle within 10…100 mcm×10…100 mcm. The core, the lower and upper shells of the polymer planar optical waveguides are made of the same polymer material, but with different refractive indices, and the lower and upper shells of the polymer planar optical waveguides are made with a thickness in the range of 10…60 mcm.

EFFECT: increase in the quality of polymer planar optical waveguides of the optoelectronic bus of a printed circuit board and reduction in losses occurring during optical signal transmission.

2 cl, 6 dwg

Description

The claimed technical solutions relate to the technology of manufacturing a printed circuit board, in particular to a method for manufacturing a high-density optical waveguide structure and to the printed circuit board itself.

Recently, people's need for information has increased dramatically, and the amount of information has increased exponentially. At the same time, the speed of information transfer (for example, which needs to be transmitted only to Internet users) annually increases several (eight) times.

In the field of long distance wired communication, fiber optic communication technology can meet these high performance requirements. However, in the field of information transmission over short distances, due to cost and technical problems, electrical connections still predominate. At the same time, electrical connections (for example, on a printed circuit board) have disadvantages such as electromagnetic interference, high losses and low bandwidth, which limit further improvement in data transmission characteristics. On the other hand, optical signal transmission channels - optical waveguides have the advantages of high bandwidth, anti-electromagnetic interference, low loss, low power consumption, small crosstalk, small physical size, etc. This makes the optical connection an effective solution for high-speed electrical circuits.

At the same time, the technology of optical printed circuit boards, based on the theory of optical waveguides, is under development, namely: features of information transmission through optical waveguides, technologies (methods) for their manufacture, as well as the connection of optical waveguides and optical fibers.

The prototype of the claimed method is a method for manufacturing a device according to the Canadian patent: CA 3098887 (A1) dated 11/21/2019, IPC G02B 6/10. G02B 6/122, G02B 6/13, "High-density optical waveguide structure and printed circuit board and preparation method thereof" - [1], which consists in applying a master stamp of the structure of optical waveguides, applying a polymer material to the core of optical waveguides, applying a polymer the material of the lower shell of optical waveguides, the application of the polymeric material of the upper shell of optical waveguides.

The prototype of the declared “PCB optical-electronic bus device” is also a Canadian patent [1], the structure of which consists of a printed circuit board base (1), on which the structures of polymer planar optical waveguides of the optoelectronic bus are applied. The high-density optical waveguide structure [1] contains a lower cladding layer, a core layer, and an upper cladding layer, while a plurality of grooves are located in the lower cladding layer, and the material of the optical waveguide fills the groove to form a core layer.

The disadvantage of the prototype method [1] is the non-disclosure in the patent of the structure of the master stamp and the specific parameters and modes of its manufacture, which does not exclude the possible contact of the layers of the optical structure with the silicon substrate of the master stamp, and as a result, to the phenomenon of uneven adhesion and poor product quality due to for possible multiple surface defects, leading to an increase in losses in the transmission of an optical signal. Also, the use of centrifugation leads to a possible non-uniform distribution of the core layer of the optical structure along the previously formed grooves and over the entire area of the fabricated structure. Which in aggregate also leads to a decrease in the quality of the resulting structure and an increase in losses in the transmission of an optical signal.

Also known analogues of the claimed method and device for its implementation according to the following patents:

- Chinese patent: CN 108415124 (A) dated 08/17/2018, IPC G02B 6/122, H05K 1/02, H05K 3/00, "High-density optical waveguide structure, printing circuit board and preparation method thereof" - [2] . The patent [2] has the same disadvantages as the prototype [1] and almost completely coincides with it.

- US patent: US2006198569 (A1) dated 09/07/2006 and US 7343060 B2 dated 03/11/2008, IPC G02B 6/12, "Light transmission and reception module, sub-mount, and method of manufacturing the sub-mount" - [3 ]. The module for transmitting and receiving light [3] includes: a macromolecular optical waveguide film in the form of a flexible tape, including an optical waveguide, an optical radiation source containing a light emitting element and the first auxiliary support for accommodating the light emitting element and for fixing one end of the macromolecular optical waveguide film on the first auxiliary fixture, so that the light emitted by the light emitting element can be transmitted to the input end surface of the optical waveguide, and the optical receiver containing the photosensitive element, and the second auxiliary support for accommodating the photosensitive element and for fixing the other end of the macromolecular optical waveguide film on the second auxiliary fixture so that the light emitted from the output end surface of the optical waveguide can be received in the photosensitive element. The disadvantage of the patent [3] in comparison with the claimed technical solutions is that the use of a macromolecular optical waveguide film in the form of a flexible tape for optical data transmission excludes the possibility of placing an optical waveguide film on the basis of a printed circuit board, and as a result, it will require additional placement of special connectors for fixing and connecting the flexible macromolecular optical waveguide film to the printed circuit board.

- Patent for the invention of Russia: RU 2561202 C2 dated 08.27.2015, IPC H04V 10/00, "Method of forming a channel for transmitting an optical signal between the components of an electronic module" - [4], which consists in the fact that a prism is made from an optically transparent material having a trapezoid at the base, the angles of which are 45, 135, 135, 45 °, and the lower side should have a length of not more than 200 mm. The prism is made with the required tolerances for linear and angular dimensions, as well as the permissible roughness, all faces of the prism, except for the bottom, are coated with aluminum using a spraying process; take a crystal that is a source of VCSEL radiation and a crystal that is a receiver of PD radiation, and glue them to the substrate, apply an insulating layer or layers to the upper plane of the crystals, form conductive interconnections from the contact pads of the crystals in a known way, open the insulating layers above the emitting and receiving areas of the corresponding crystals and set the prism with the calculated accuracy to the appropriate place, fix it with a polymer layer around the perimeter or a thin layer of photoresist, which is applied to the contact surfaces before installing the prism, and apply insulating layers. In the case when it is required to reduce the divergence of the light beam, microlenses can be installed in the cavity above the emitting and receiving areas formed after the opening of the insulating layers. The disadvantage of the patent [4] in comparison with the claimed technical solutions is the non-disclosure in the patent of materials, parameters and modes of manufacturing a device - a channel for transmitting an optical signal in the form of a prism, which has a trapezoid at its base, the angles of which are 45, 135, 135, 45 °, and the underside must have a length of no more than 200 mm.

- Patent for the invention of Russia: RU 2568341 O dated 11/20/2015, IPC G02B 6/00, "Method of forming a channel for transmitting an optical signal between the components of an electronic module" - [5], consisting in the fact that from a material that is selected based on wavelength of the used optical radiation, an optical part is made, which is an optical radiation waveguide made in the form of two mirror-symmetric diffraction gratings and a straight section between them. A VCSEL radiation source chip and a PD radiation receiver chip are taken and glued to a substrate. An insulating layer or insulating layers is applied to the upper plane of the crystals, conductive interconnections are formed from the contact pads of the crystals in a known manner, the insulating layers are opened above the emitting and receiving pads of the corresponding crystals, and the optical part is installed with the calculated accuracy at the appropriate place. The part is fixed with a polymer layer around the perimeter or a thin layer of photoresist, which is applied to the contact surfaces before installing the optical part, and insulating layers are applied. The disadvantage of the patent [5] in comparison with the claimed technical solutions is also the non-disclosure in the patent of the parameters and modes of manufacturing the device - an optical part, which is an optical radiation waveguide made in the form of two mirror-symmetric diffraction gratings and a straight section between them.

- Russian utility model patent: RU 83626 U1 dated 06/10/2009, IPC G02B 6/34, "Optical planar waveguide" - [6], consisting of a central optically transparent waveguide layer, boundary layers, a radiation input device and a radiation output device in the form of a diffraction grating. At the same time, the diffraction grating of the radiation output device is made with a variable depth of modulation, increasing along the length of the grating in the direction from the beginning of the radiation output according to an exponential dependence. The disadvantage of the patent [6] in comparison with the claimed technical solutions is that the description of the patent does not provide materials, parameters and modes of manufacturing a device - an optical planar waveguide, consisting of a central optically transparent waveguide layer, boundary layers, a radiation input device and a radiation output device in the form of a diffraction grating. This does not allow to reproduce the device [6] without additional development.

- US patent US2003179978 (A1) dated 09/25/2003 and US6970610 (B2) dated 11/29/2005, IPC F21V 8/00, G02B 6/122, G02B 6/43, "Optical transmission sheet, optoelectric apparatus, and optical transmission method" - [7]. This optical transmission device includes a planar waveguide for transmitting an optical signal, a light emitting unit for inputting a light beam into the planar waveguide, and a setting block for setting the propagation angle of the light beam transmitted in the planar waveguide. In a planar waveguide, a plurality of light rays with different propagation angles are transmitted. The disadvantage of using the device according to the patent [7] is the use of a flat optical layer for transmitting optical radiation instead of planar optical waveguides of rectangular cross section, as in the claimed technical solution.

The above shortcomings of the prototype and analogs pose the problem of improving the quality of polymer planar optical waveguides optoelectronic bus printed circuit board. Improving their quality will ultimately lead to a reduction in optical signal transmission losses. And the quality of polymer planar optical waveguides of the optical-electronic bus of a printed circuit board can only be improved by improving the method of their manufacture.

The essence of the claimed method of manufacturing the structure of an optical-electronic bus on the surface of a printed circuit board consists in manufacturing a master stamp of the structure of optical waveguides of an optoelectronic bus, applying a polymeric material to the core of optical waveguides, applying a polymeric material to the lower shell of optical waveguides, and applying a polymeric material to the upper shell of optical waveguides. At the same time, for the manufacture of a master stamp, the photolithography method is used with sequential application of two of its layers and the formation of a two-layer structure of the master stamp from one material, after which a layer of an adhesion modifier (for example, hexamethyldisilazane - (HMDS)) is applied to the formed structure of the master stamp, then the polymeric material of the core of the optical waveguides is applied to the master stamp by pouring, followed by drawing with a squeegee along the master stamp, the polymeric material of the lower shell is applied, followed by the squeegee drawing along a frame of a given thickness, the polymeric material of the lower shell is covered with a base (printed circuit board) with a pre-activated contact surface and kept (for example, at an elevated temperature) until the polymer materials are completely cured, then the base is removed - the printed circuit board with the formed layers of the lower shell and the core of the optical waveguides from the master stamp, after which the polymer material of the upper shell is applied, followed by broaching with a squeegee along a frame of a given (increased) thickness.

The essence of the PCB optical-electronic bus device is that it contains a printed circuit board base, on which the structures of polymer planar optical waveguides of the optoelectronic bus are deposited. At the same time, the cross section of the cores of polymer planar optical waveguides has a rectangular shape with the dimensions of a rectangle in the ranges of 10…100 µm × 10…100 µm (for example, 88 µm × 63 µm), the core, lower and upper shells of polymer planar optical waveguides are made of the same the same polymeric material (for example, SKTN rubber according to GOST 13835 - 73), but having different refractive indices (by changing the ratio of the initial components of the polymeric material to ensure total internal reflection at the core-shell boundary (lower or upper)), and the lower and upper shells of polymeric planar optical waveguides are made with a thickness in the range of 10…60 µm (for example, 30 µm).

The technical result of the claimed inventions is to improve the quality of polymer planar optical waveguides of the optical-electronic bus of the printed circuit board and to reduce losses in the transmission of an optical signal.

The introduction of a distinctive feature of the method "for the manufacture of a master stamp, the method of photolithography is used with the successive application of two of its layers and the formation of a two-layer structure of the master stamp from one material" makes it possible to reduce the heterogeneity of the adhesion of the polymeric materials of the cores and the lower shell to the master stamp by eliminating the contact of polymeric materials with a base on which the topology of the master stamp is made using photolithography. The homogeneity of adhesion allows the formation of better products in comparison with single-layer master stamps made by known methods.

The introduction of a distinctive feature of the method “after which a layer of an adhesion modifier (for example, hexamethyldisilazane - (HMDS)) is applied to the formed structure of the master stamp” makes it possible to reduce the adhesion of polymeric materials of the cores and the lower cladding of optical waveguides to the maximum, which helps to eliminate growth factors in the number of surface defects, which occur when the cured structure of optical waveguides is removed from the master stamp and lead to an increase in signal losses in them. Therefore, the use of an adhesion modifier improves the quality of fabricated structures of optical waveguides and reduces signal losses in them.

The introduction of a distinctive feature of the method “then, the polymeric material of the core of optical waveguides is applied to the master stamp by pouring, followed by drawing with a squeegee over the master stamp” makes it possible to uniformly (unlike centrifugation) fill the volumetric (3-dimensional) topology of the master stamp with the polymeric material of the cores optical waveguides to avoid air voids in the cured core of the optical waveguide. Elimination of the reasons for the occurrence of air voids helps to reduce signal losses in the structure of optical waveguides and improve the quality of their manufacture.

The introduction of a distinctive feature of the method “the polymeric material of the lower shell is applied followed by drawing with a squeegee along a frame of a given thickness” makes it possible to produce a lower shell of optical waveguides uniform in thickness to facilitate subsequent alignment with radiation input / output devices and improve the quality of the formed optical-electronic bus of the printed circuit board.

The introduction of a distinctive feature of the method "the polymer material of the lower shell is covered with a base (printed circuit board) with a pre-activated contact surface and kept (for example, at elevated temperature) until the polymer materials are completely cured" makes it possible to ensure the necessary adhesion of the polymer material of the lower shell of optical waveguides to the printed base, which creates conditions for the formation of high-quality optical-electronic tires of printed circuit boards, which are not characterized by peeling of the polymer structures of optical waveguides.

The introduction of the distinguishing feature of the method “then, the base is removed - a printed circuit board with the formed layers of the lower shell and the core of the optical waveguides from the master stamp, after which the polymer material of the upper shell is applied, followed by drawing a squeegee along a frame of a given (increased) thickness” makes it possible to manufacture a high-quality structure of optical waveguides without the use of expensive photolithographic equipment and polymer materials with a relatively low signal transmission loss.

The introduction of the distinctive feature of the device “the cross section of the cores of polymer planar optical waveguides has a rectangular shape with the dimensions of a rectangle in the range of 10…100 µm × 10…100 µm (for example, 88 µm × 63 µm)” makes it possible to manufacture both single-mode and multimode polymer planar optical waveguides rectangular section in the structure of the optical-electronic bus of the printed circuit board. Reducing the core size to less than 10 μm leads to a decrease in the efficiency of radiation input from a standard (glass) optical fiber, and, consequently, to an increase in radiation losses. And increasing the size of more than 100 microns leads to an increase in the signal dispersion in the core of the optical waveguide, which also leads to a decrease in the quality of the transmitted signal.

The introduction of a distinctive feature of the device "the core, lower and upper shells of polymer planar optical waveguides are made of the same polymer material (for example, SKTN rubber according to GOST 13835 - 73), but having different refractive indices (by changing the ratio of the initial components of the polymer material for ensuring total internal reflection at the core-cladding (lower or upper) interface” makes it possible to eliminate the prerequisites for the occurrence of internal stresses in the structure of optical waveguides due to the mismatch of the temperature coefficients of linear expansion of various materials. In the proposed structure of the device, the use of the same polymeric material reduces the likelihood of increasing signal losses due to internal stresses in the structure of the optical-electronic bus of the printed circuit board and improves its quality.

The introduction of the distinctive feature of the device "the lower and upper shells of polymer planar optical waveguides are made with a thickness in the range of 10 ... to reduce signal loss during the input / output of optical radiation from the optical fiber.

The claimed technical solutions (method and device) are presented in graphic materials, namely:

In FIG. 1 shows the sequence of operations of the technology (method) for manufacturing the structure of the optical-electronic bus of a printed circuit board according to the prototype [1] in sections, where:

1a) - printed base with a layer of the lower shell of the optical waveguide;

1b) - the topology of the master stamp in the process of imprinting in the lower shell of the optical waveguide;

1c) - the lower shell of the optical waveguide at the moment of imprinting the master stamp;

1d) - the lower shell of the optical waveguide with the formed grooves after the imprint of the master stamp;

1e) - the lower shell of the optical waveguide with the polymeric material of the cores of the optical waveguides deposited into the grooves;

1e) - the structure of optical waveguides with a deposited layer of the upper cladding.

In FIG. 2 shows the sequence of operations of the claimed method (technology) for manufacturing the structure of an optical-electronic bus of a printed circuit board in sections, where:

2a) - silicon substrate with the first layer of the master stamp applied;

2b) - silicon substrate with the second layer of the master stamp deposited on top of the first layer;

2 c) - the topology of a two-layer master stamp formed by photolithography;

2d) - two-layer master stamp coated with a layer of adhesion modifier hexamethyldisilazane;

2e) - a two-layer master stamp with a layer of optical waveguide cores applied by pouring followed by a squeegee drawing;

2f) - a two-layer master stamp with a layer of cores and applied by pouring, followed by a squeegee drawing along the frame with a layer of the lower shell;

2g) - attaching the printed base to the lower layer of the optical waveguide shell and holding the polymer structure for its curing;

2h) - separation of the printed base with a cured structure of polymeric planar optical waveguides;

2i) - formed part of the structure of optical waveguides from the lower shell and core;

2k) - the structure of optical waveguides with a deposited layer of the upper cladding.

In FIG. 3 - scanning electron microscopy (SEM image) of the master stamp.

In FIG. 4 - photograph of the obtained structure (its part) of the optical-electronic bus of the printed circuit board according to the claimed method (technology).

In FIG. 5 is a diagram of an experimental study of the obtained structure (its part) of the optical-electronic bus of the printed circuit board according to the claimed method (technology).

In FIG. 6 - photograph of the experimental study of the obtained structure (its part) of the optical-electronic bus of the printed circuit board according to the claimed method (technology).

In the figures, the numbers indicate: 1 - printed base, which can be made of FR4 material; 2 - polymer layer of the lower shell of optical waveguides; 3 - topology material of the master stamp of optical waveguides (3.1 and 3.2 - layers of a two-layer master stamp from the same material); 4 - the base of the master stamp, which can be made of silicon; 5 - polymer layer of the cores of optical waveguides; 6 - polymer layer of the upper shell of optical waveguides; 7 - layer of adhesion modifier, which can be made of hexamethyldisilazane; 8 - polymeric planar optical waveguide (generalized and including layers of the core (5), lower shell (2) and upper shell (6)); 9 - optical fiber for input/output of radiation; 10 - V-shaped grooves for "butt" alignment of the optical fiber (9) with the polymer planar optical waveguide (8); 11 - radiation source; 12 - radiation receiver (tester).

The method of manufacturing the structure of an optoelectronic bus on the surface of a printed circuit board (1) according to the prototype [1] consists (see Fig. 1) in using a master stamp (3, 4) of the structure of optical waveguides of an optoelectronic bus, applying a polymer material of the optical core waveguides (5), applying the polymeric material of the lower shell of the optical waveguides (2), and applying the polymeric material of the upper shell (6) of the optical waveguides. In this case, at the beginning, a polymeric material of the lower shell (2) is applied to the printed base (1), in which then, by imprinting a master stamp (3, 4), grooves are formed, the topology of which corresponds to the cores of the formed structure of optical waveguides. Next, the grooves are filled by pouring and centrifuging the polymeric material of the cores (5) of the optical waveguides, then the cores and the lower shell of the optical waveguides are covered with a layer of the upper shell (6).

Unlike the prototype [1], the claimed method of manufacturing the optoelectronic bus structure on the surface of the printed circuit board (1) (see Fig. 2) consists in using soft lithography technology - a subspecies of nanoimprint lithography, which includes the production of a master stamp (3.1, 3.2 - two-layer topology, 4 - bases) of the structure of optical waveguides of an optical-electronic bus, applying a polymeric material of the core (5) of optical waveguides, applying a polymeric material of the lower shell (2) of optical waveguides, attaching the base of the printed circuit board (1) to the lower shell (2 ) of optical waveguides, removing the cured structure of optical waveguides (5, 2, 1) from the master stamp (3.1, 3.2, 4) and applying the polymer material of the upper shell (6) of optical waveguides. At the same time, the topology of the master stamp is formed on the silicon base (4) by photolithography, which corresponds to the reverse topology of the optical layer of the cores of polymer planar optical waveguides of the optical-electronic bus of the printed circuit board: in areas where cores (5) of optical waveguides should then be made, in On the master stamp (3.1, 3.2, 4), grooves are formed with a configuration and dimensions corresponding to the topology of the layer of cores (5) of polymeric planar optical waveguides. For the manufacture of a master stamp (3.1, 3.2, 4), light-sensitive photopolymer materials can be used, for example, photoresists of the SU-8 2000, SU-8 3000 groups, which can be applied in layers with a thickness in the range of 10 ... 65 microns. To avoid possible contact of the core material (5) with the silicon base (4) of the master stamp (3.1, 3.2, 4), a continuous layer of material is applied to the silicon base (4) at the first stage of the master stamp (3.1, 3.2, 4) formation. master stamp (3.1), then a layer (3.2) is applied, the thickness of which corresponds to the height of the layer of optical waveguide cores. In the second layer (3.2), the topology of the master stamp is formed using the technological operations of photolithography. A layer of adhesion modifier (7) (for example, hexamethyldisilazane - (HMDS)) is applied to the formed structure of the master stamp (3.1, 3.2, 4) to reduce the adhesion of the layers of the core (3) and the lower cladding (2) of optical waveguides to the topology of the master stamp (3.1, 3.2, 4 and 7) and to ensure defect-free extraction of the formed structure of optical waveguides after they have been cured in the master die (3.1, 3.2, 4 and 7). Then, the polymeric material of the core (5) of the optical waveguides is applied to the master stamp (3.1, 3.2, 4 and 7) by pouring followed by drawing with a squeegee along the master stamp (3.1, 3.2, 4 and 7). To do this, the master stamp (3.1, 3.2, 4 and 7) is fixed using a special frame that is 100 ... an excess amount of the material of the cores (5) of the optical waveguides is poured, previously degassed in a vacuum chamber. Next, using a squeegee, for example, silicone, rub the material of the cores (5) into the grooves of the master stamp (3.1, 3.2, 4 and 7). Excess core material (5) is removed with a squeegee. Then the frame is removed and the master stamp (3.1, 3.2, 4 and 7) with the grooves filled with the material of the cores (5) of the optical waveguides is degassed in a vacuum chamber, after which it is kept, for example, at an elevated temperature, until the material of the cores (5) of the optical waveguides is cured. waveguides. Next, a polymeric material of the lower shell (2) is applied, followed by drawing with a squeegee along a frame of a given thickness. To do this, the master stamp with grooves filled with hardened cores (5) of optical waveguides is fixed with frames, the thickness of one of which corresponds to the thickness of the lower shell (2) of optical waveguides, and the other was used earlier at the stage of manufacturing cores (5) of optical waveguides to fix the master -stamp. The width of the first frame exceeds the width of the second frame so that the open area is equal to the area of the printed base (1), on the surface of which the optical waveguide structure is fabricated. After that, the uncured material of the lower shell (2) is covered with a base (1) (printed circuit board) with a pre-activated contact surface to increase the adhesion of the material of the lower shell (2) to the printed base (1) and prevent the structure of optical waveguides from peeling off the printed base (1) . Then the structure is kept, for example, at an elevated temperature from 25°C to 100°C until complete curing of the polymeric materials, respectively, from 48 hours to 30 minutes. Upon completion of the complete curing of the polymeric materials of the optical waveguides, the base - the printed circuit board (1) with the formed layers of the lower shell (2) and the core (5) of the optical waveguides is removed from the master stamp (3.1, 3.2, 4 and 7). After that, the polymer material of the upper shell (6) is applied by drawing a squeegee along the frame with a thickness corresponding to the sum of the thicknesses of the printed base (1), lower shell (2), core layer (5) and upper shell (6).

The claimed device of the optical-electronic bus of the printed circuit board consists in that it contains the base of the printed circuit board (1), on which the structures of polymeric planar optical waveguides (8) of the optical-electronic bus are deposited. In this case, the cross section of the cores (5) of the polymeric planar optical waveguides has a rectangular shape with the dimensions of a rectangle in the ranges of 10...100 µm × 10...100 µm. In the device manufactured by the applicant, the cross-sectional dimensions of the layer of cores (5) were 88 μm x 63 μm. The core (5), lower (2) and upper (6) shells of polymeric planar optical waveguides are made of the same polymeric material - rubber SKTN according to GOST 13835 - 73, but having different refractive indices, respectively 1.404 - cores (5) and 1.41 - lower (2) and upper (6) shells. This ensures total internal reflection at the core (5) - shell (lower (2) or upper (6)) interface. The lower (2) and upper (5) shells of polymeric planar optical waveguides are made with a thickness in the range of 10…60 µm. In the device manufactured by the applicant, the dimensions of the lower (2) and upper (5) shells were 30 μm.

The operation of the claimed device consists in the fact that optical radiation with a wavelength of the near-IR range of 830 ... by means of a "butt" interface with an optical fiber (9) fixed in the radiation input element in the form of a V-shaped groove (10) and connected to the radiation source (11). Optical radiation is transmitted through polymer planar optical waveguides (8) by providing total internal reflection at the "core (5) - shell (2, 6)" interface of the optical waveguide (8). Then the optical radiation enters the output end of the polymer optical waveguide (8) and is transmitted to the input of the optical fiber (9) fixed in the radiation output element in the form of a V-shaped groove (10) and connected to a receiver (12), for example, a tester, optical radiation.

According to the results of measuring the characteristics of the claimed device, the signal loss in polymer planar optical waveguides (8) was no more than 10 dB, which corresponds to the characteristics of analogues from well-known literary sources, for example: Bamiedakis N. el. "A 40 Gb / s Optical Bus for Optical Backplane Interconnections" - JOURNAL OF LIGHTWAVE TECHNOLOGY, 2014, vol. 32, no. 8, p. 1526-1537 - [8].

The printed circuit board of the optoelectronic bus may also contain one or more layers of metal conductors for electrical switching, made in known ways, for example, as in [1] and [2].

The manufacture of the structure of the optical-electronic bus of a printed circuit board according to the claimed method, as well as the device itself, together with the restrictive and distinctive features of the claims, is new in relation to well-known manufacturing methods and devices for this purpose, and, therefore, meets the "novelty" criterion.

The set of features of the claims is not known at this level of development of technology and does not follow from the well-known methods for manufacturing the structure of an optical-electronic bus of a printed circuit board, namely, the production of a two-layer topology of a master stamp by photolithography, coated with an adhesion modifier layer, as well as the formation of a structure of polymer planar optical waveguides in the structure of the master stamp with the subsequent attachment of the base of the printed circuit board, which proves compliance with the criterion of "inventive step" (this is also evidenced by a patent search and a link to sources of information [1] -[8]).

The implementation of the claimed method and device can be carried out by known and used methods, technologies and equipment, which implies compliance with the criterion of "industrial applicability".

Literature:

1. Canadian patent: CA 3098887 (A1) dated 11/21/2019, IPC G02B 6/10. G02B 6/122, G02B 6/13, "High-density optical waveguide structure and printed circuit board and preparation method thereof" - prototype.

2. China patent: CN 108415124 (A) dated 08/17/2018, IPC G02B 6/122, H05K 1/02, H05K 3/00, "High-density optical waveguide structure, printing circuit board and preparation method thereof".

3. US patent: US2006198569 (A1) dated 09/07/2006 and US 7343060 B2 dated 03/11/2008, IPC G02B 6/12, "Light transmission and reception module, sub-mount, and method of manufacturing the sub-mount".

4. Patent for the invention of Russia: RU 2561202 C2 dated 08/27/2015, IPC H04V 10/00, "Method of forming a channel for transmitting an optical signal between the components of an electronic module."

5. Patent for the invention of Russia: RU 2568341 C1 dated 11/20/2015, IPC G02B 6/00, "Method of forming a channel for transmitting an optical signal between the components of an electronic module."

6. Russian utility model patent: RU 83626 U1 dated 06/10/2009, IPC G02B 6/34, "Optical planar waveguide".

7. US patent US2003179978 (A1) dated September 25, 2003 and US6970610 (B2) dated November 29, 2005, IPC F21V 8/00, G02B 6/122, G02B 6/43, "Optical transmission sheet, optoelectric apparatus, and optical transmission method ".

8. Bamiedakis N. el. "A 40 Gb/s Optical Bus for Optical Backplane Interconnections" - JOURNAL OF LIGHTWAVE TECHNOLOGY, 2014, vol. 32, no. 8, p. 1526-1537.

Claims (16)

1. A method for manufacturing an optoelectronic bus structure on a printed circuit board surface, which consists in production of a master stamp of the structure of optical waveguides of an optical-electronic bus, application of a polymeric material to the core of optical waveguides, deposition of polymeric material of the lower shell of optical waveguides, application of a polymeric material for the upper shell of optical waveguides, characterized in that for the manufacture of a master stamp, the photolithography method is used with the successive application of two of its layers and the formation of a two-layer structure of the master stamp from one material, after which a layer of adhesion modifier is applied to the formed structure of the master stamp, then, the polymeric material of the core of the optical waveguides is applied to the master stamp by pouring, followed by drawing with a squeegee along the master stamp, the polymeric material of the lower shell is applied, followed by drawing with a squeegee along a frame of a given thickness, the polymeric material of the lower shell is covered with the base of the printed circuit board with a pre-activated contact surface and kept until the polymeric materials are completely cured, then the base is removed - a printed circuit board with the formed layers of the lower shell and the core of the optical waveguides from the master stamp, after that, the polymeric material of the upper shell is applied, followed by broaching with a squeegee along a frame of a given thickness. 2. The device of the optical-electronic bus of the printed circuit board, containing the base of the printed circuit board, on which the structures of polymer planar optical waveguides of the optical-electronic bus are deposited, characterized in that the cross section of the cores of polymer planar optical waveguides has a rectangular shape with the dimensions of a rectangle in the ranges of 10…100 µm × 10…100 µm, in this case, the core, lower and upper shells of polymer planar optical waveguides are made of the same polymer material, but having different refractive indices, and the lower and upper shells of polymeric planar optical waveguides are made with a thickness in the range of 10…60 µm.

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