KR20120129993A - Plasma-polymerized polymer coating - Google Patents

Abstract

A substrate comprising an insulating material, a plurality of conductive tracks present on at least one surface of the substrate, at least one electrical or electro-optical component connected to the at least one conductive track, and the substrate, the plurality of conductive tracks and at least one electrical Or an electrical or electronic optical assembly comprising a continuous coating comprising a polymer polymerized with plasma that completely covers the surface of at least one of the electronic optical components.

Description

Plasma Polymerized Polymer Coatings {PLASMA-POLYMERIZED POLYMER COATING}

The present invention relates to a plasma-polymerized polymer coating and a method comprising the coating, used for coating electrical and electro-optical assemblies and components.

Protective coatings have been used for many years in the electronics industry to protect electrical assemblies from exposure to the environment during operation. The protective coating is a thin, flexible layer of protective lacquer that matches the contour of the PCB and its components. Protective coatings protect circuits from chemicals causing corrosion (eg salts, solvents, ferrols, oils, acids and environmental contaminants), humidity / liquefaction, vibration, current leakage, electrophoresis and dendritic growth. . Current protective coatings typically have a thickness of 25 to 200 μm and are generally based on epoxy resins, acrylic resins or silicone resins. All of these materials are deposited as a liquid that must be cured after being applied to the assembly. Recently expensive parylene has also been used as a protective coating. Parylene is typically deposited using conventional chemical vapor deposition techniques well known to those skilled in the art.

There are a number of disadvantages currently associated with protective coatings. The technique used to deposit the coating requires that the contacts to which the assembly is connected to another device are masked prior to coating so that the protective coating does not cover the contacts. Coated contacts are not capable of electrical connection with other devices because the protective coating is thick and insulated.

Furthermore, it is currently very difficult and expensive to remove the protective coating when re-working of the electrical assembly is needed. Without prior removal, it is impossible to solder or weld through the coating. In addition, due to the liquid techniques commonly used to deposit such protective coatings, defects, such as bubbles, tend to form in the coating. This defect reduces the protective ability of the protective coating. A further problem of the protective coating in the prior art is that due to the liquid technique used during coating, it is difficult to deposit the coating under the components on the assembly.

Surprisingly, the inventors have found that plasma polymerized polymers can be used to form good protective coatings on electrical and electro-optic assemblies. Such coatings are not only continuous and substantially defect free, but may also overcome the problems with the existing coatings described above. Furthermore, the plasma polymerized polymer coating of the present invention is easy and relatively inexpensive to deposit on the device.

Thus, the present invention provides a substrate comprising an insulating material, a plurality of conductive tracks present on at least one surface of the substrate, at least one electrical or electro-optical component connected to the at least one conductive track, and the substrate, the plurality of conductive tracks. And a continuous coating comprising a plasma polymerized polymer completely covering the surface of at least one of the at least one electrical or electronic optical component.

The present invention comprises (a) a substrate comprising an insulating material, a plurality of conductive tracks present on at least one surface of the substrate, and at least one electrical or electronic optical component connected to the at least one conductive track. Providing an electrical or electronic optical assembly, and (b) a continuous coating comprising a polymer completely covering the surface of the substrate, the plurality of conductive tracks and at least one of the at least one electrical or electronic optical component. It further provides a method comprising the step of depositing using plasma polymerization.

The invention further provides an electrical or electro-optical assembly obtainable by the method defined above.

The invention further provides an electrical or electro-optical component completely covered with a continuous coating comprising a polymer polymerized with plasma.

The present invention comprises the steps of (a) applying the electrical or electronic light assembly as defined above to a plasma removal process such that the continuous coating is removed, and then (b) selectively reprocessing the electrical or electronic light assembly. And then (c) selectively depositing a continuous replacement coating comprising a polymer that completely covers the surface of the substrate, the plurality of conductive tracks and at least one of the at least one electrical or electronic optical component. It further provides a method including the steps of:

The present invention includes soldering through a continuous coating of electrical or electronic optical assemblies as defined above to form solder joints between additional electrical or electronic optical components and at least one conductive track. It further provides a method, wherein the solder joint is located adjacent to the continuous coating.

The present invention provides a surface finish comprising (a) a substrate comprising an insulating material, a plurality of conductive tracks present on at least one surface of the substrate, and a halohydrocarbon polymer covering at least a portion of the plurality of conductive tracks. Applying an electrical or electronic optical assembly comprising a coating and at least one electrical or electronic optical component connected to at least one conductive track through the surface finishing coating to a plasma removal process to remove the surface finishing coating And then (b) plasma containing a continuous coating comprising a polymer as defined above that completely covers the surface of the substrate, the plurality of conductive tracks and at least one of the at least one electrical or electro-optical component. It further provides a method comprising the step of depositing using polymerization.

The present invention provides a surface finish coating comprising (a) a substrate comprising an insulating material, a plurality of conductive tracks present on at least one surface of the substrate, and a halohydrocarbon polymer covering at least a portion of the plurality of conductive tracks. Applying an electrical or electronic light assembly comprising the same to a plasma removal process, wherein the surface finish coating is removed, and then (b) connecting the electrical or electronic light component to at least one conductive track, and then ( c) depositing, using plasma polymerization, a continuous coating comprising a polymer as defined above that completely covers the surface of the substrate, the plurality of conductive tracks and at least one of the at least one electrical or electronic optical component. It further provides a method comprising the step of.

The invention further provides an electrical or electro-optical assembly having a protective coating comprising a polymer polymerized with plasma as defined above.

The invention further provides for the use of a polymer polymerized with plasma as defined above as a protective coating for an electrical or electronic optical assembly.

The present invention further provides a method of protectively treating and coating an electrical or electro-optical assembly comprising depositing a polymer as defined above using plasma polymerization.

1A shows the results of X-ray photoelectron spectroscopic analysis of plasma-polymerized fluoropolymers.
1B shows the results of X-ray photoelectron spectroscopy analysis of fluoropolymers obtained by standard polymerization techniques.
FIG. 2A shows an electron microscope image of the fluoropolymer coating polymerized with the plasma of the present invention and the smooth physical properties of the coating.
FIG. 2B shows an image of the PTFE coating under an electron microscope, wherein the PTFE coating is deposited by standard polymerization techniques with a structure where the fibrils are clearly visible.
3-7 illustrate electrical assemblies of certain embodiments.
8 illustrates an electron light assembly of a particular embodiment.
9 illustrates an electrical component of a particular embodiment.
10 shows an example of an apparatus that can be used to form the polymerized polymer coating with the plasma of the present invention.
11A, 11B and 11C are flowcharts illustrating the method of a particular embodiment.

The present invention relates to electrical and electron light assemblies. The electrical assembly typically includes at least one electrical component. The electron light assembly typically includes at least one electronic light component, and may optionally further include at least one electrical component. The electrical or electro-optical assembly is preferably a printed circuit board.

Continuous coatings of the present invention include polymers polymerized with plasma. The continuous coating of the present invention can prevent damage caused by the environment to the electrical or electro-optical assemblies. Damage caused by the environment is usually caused by corrosion effects due to atmospheric components (eg oxygen SO ₂ , H ₂ S and / or NO ₂ ) and / or moisture at ambient or elevated temperatures. In addition, the continuous coatings of the present invention may be continuously connected to protect electrical and electro-optical assemblies applied over a larger temperature range than current protective coatings that may be degraded at higher temperatures.

The continuous coating of the present invention is preferably a protective coating.

Polymers polymerized with plasma are inherent classes of polymers that cannot be prepared by conventional polymerization methods. Plasma polymerized polymers have a very disordered structure and are generally heavily crosslinked, contain random branching and have some reaction sites. As such, polymers polymerized with plasma are chemically distinct from polymers produced by conventional polymerization methods known to those skilled in the art. This chemical and physical distinction is well known, for example Plasma Polymer Films , Hynek Biederman , Imperial College It is described in Press 2004 .

Polymers polymerized with plasma are typically obtainable by plasma polymerization techniques as defined in more detail below.

Plasma polymerized polymers are typically plasma polymerized hydrocarbons, halohydrocarbons, silicones, siloxanes, silanes, silazanes or stannanes.

Hydrocarbons polymerized with plasma are typically straight and / or branched polymers, optionally with cyclic moieties. Said cyclic moiety is preferably alicyclic rings or aromatic rings, more preferably aromatic rings. Preferably, the hydrocarbon polymerized with plasma does not contain cyclic moieties. Preferably, the hydrocarbon polymerized with plasma is a branched polymer.

Halohydrocarbons polymerized with plasma are typically straight and / or branched polymers, optionally comprising cyclic moieties. Said cyclic moiety is preferably an aliphatic ring or an aromatic ring, more preferably an aromatic ring. Preferably, the halohydrocarbons polymerized with plasma do not contain cyclic moieties. Preferably, the halohydrocarbons polymerized with plasma are branched polymers.

Each of the plasma polymerized hydrocarbons and halohydrocarbons comprising an aromatic moiety is an aromatic hydrocarbon and aromatic halohydrocarbons (eg aromatic fluorohydrocarbons) polymerized with plasma. Examples include polystyrene polymerized with plasma and parylene polymerized with plasma. Particular preference is given to parylene polymerized with plasma. Parylene polymerized with plasma may or may not be substituted with one or more substituents. Preferred substituents include halogens, most preferably fluorine. Parylene substituted with one or more halogen atoms is haloparylene. Parylene substituted with one or more fluorine atoms is fluoroparylene. Most preferred is unsubstituted parylene.

Hydrocarbons polymerized with plasma optionally contain heteroatoms selected from N, O, Si and P. Preferably, however, the hydrocarbon polymerized with plasma does not contain N, O, Si and heteroatoms.

Halohydrocarbons polymerized with plasma optionally contain heteroatoms selected from N, O, Si and P. However, halohydrocarbons polymerized with plasma do not contain N, O, Si and P heteroatoms.

Hydrocarbons polymerized with oxygen-containing plasmas preferably include carbonyl moieties, more preferably ester and / or amide moieties. A preferred class of oxygen polymerized hydrocarbon polymers is plasma polymerized acrylate polymers.

Halohydrocarbons polymerized with oxygen-containing plasmas preferably comprise carbonyl moieties, more preferably ester and / or amide moieties. A preferred class of oxygen-containing plasma polymerized halohydrocarbon polymers is plasma-polymerized haloacrylates polymers, for example fluoroacrylate polymers polymerized with plasma. .

Hydrocarbons polymerized with plasma containing nitrogen are preferably nitro, amine, amide, imidazole, diazole, trizole and / or tetraazole residues. moieties).

Halohydrocarbons polymerized with nitrogen-containing plasmas preferably include nitro, amine, amide, imidazole, diazole, triazole and / or tetraazole residues.

Plasma polymerized silicon, siloxane, silane and silazane are optionally substituted with one or more fluorine atoms. However, it is preferred that silicone, siloxane, silane and silazane not be substituted. Preferred silazanes are hexamethyl disilazane.

Preferably, the polymer polymerized with plasma is halohydrocarbon polymerized with plasma, more preferably, plasma-polymerized fluorohydrocarbon. Most preferably, the polymer polymerized with the plasma is a fluorohydrocarbon polymerized with a plasma which is branched and contains no heteroatoms.

As used herein, the term halo is preferably fluorine, chloro, bromo and iodine. Fluorine and chloro are preferred, most preferred is fluorine. Halogen has the same meaning.

The assembly of the present invention can be prepared by depositing a polymer by plasma polymerization. Plasma polymerization is generally an effective technique for depositing thin coatings. In general, plasma polymerization provides a good coating because the polymerization reaction takes place in place. As a result, the plasma polymerized polymer is generally deposited in small recesses, but under certain components and in vias that are not accessible by normal liquid coating techniques.

In addition, the polymer formed in place can provide good adhesion to the surface, where a coating is applied to the surface because the polymer generally reacts with the surface during deposition. Therefore, in certain circumstances, polymers polymerized with plasma may be deposited on materials on which other protective coatings cannot be deposited.

A further advantage of the plasma polymerization technique of the present invention is that there is no need to dry / cure the coating after deposition. Prior art techniques for coatings require a drying / curing step, which forms a curing / drying defect on the surface of the coating. Plasma polymerization can avoid the formation of curing / drying defects.

Plasma deposition may be performed in a reactor that generates a gas plasma comprising ionized gas ions, electrons, atoms, and / or neutral species. The reactor may comprise a chamber, a vacuum system, and one or more energy sources, but any suitable type of reactor configured to generate a gas plasma may be used. The energy source may comprise a suitable device configured to convert one or more gases into a gas plasma. Preferably, the energy source comprises a heater, a radio frequency (RF) generator, and / or a microwave generator.

In certain embodiments, the electrical or optical assembly can be located in a chamber of the reactor and a vacuum system can be used to pump the chamber down to a pressure in the range of 10 ⁻³ to 10 mbar. Thereafter, one or more gases can be pumped into the chamber and the energy source can generate a stable gas plasma. The one or more precursor compounds may then enter the gas plasma of the chamber as a gas and / or a liquid. Upon entering the gas plasma, the precursor compound may be ionized and / or ionized and decomposed to generate active species having a range in the plasma that is polymerized to generate a polymer coating.

The fluorohydrocarbons polymerized with plasma are preferably obtained by plasma polymerization of at least one precursor compound which is a hydrocarbon substance containing a fluorine atom. Preferred hydrocarbon materials including fluorine atoms are perfluoroalkanes, perfluoroalkenes, perfluoroalkynes, fluoroalkanes, fluoroalkenes, fluoroalkynes. Examples include C ₃ F ₆ and C ₄ F ₈ .

Other preferred precursor compounds are fluorochloroalkanes, fluorochloroalkenes and fluorochloroalkynes. Examples include C ₂ F ₃ Cl and C ₂ F ₄ Cl ₂ .

The parylene polymerized by plasma is preferably obtainable by plasma polymerization of di-p-xylylene, xylene or xylenes.

The precise nature and composition of the polymer coating polymerized with plasma typically depends on one or more of the following conditions: (i) the selected plasma gas; (ii) the specific precursor compound (s) used; (iii) the amount of precursor compound (s) (can be determined by the combination of pressure and flow rate of the precursor compound (s)); (iv) the proportion of precursor compound (s); (v) order of precursor compound (s); (vi) plasma pressure; (vii) plasma drive frequency; (viii) pulp width timing; (ix) coating time; (x) plasma power (including peak and / or average plasma power); (xi) chamber electrode placement; And / or (xii) preparation of the incoming assembly.

Typically, the plasma drive frequency is 1 kHz to 1 GHz. Typically, the plasma power is 500 to 10000 W. Typically, the mass flow rate is between 5 and 2000 sccm. Typically, the operating pressure is 10 to 500 mTorr. Typically the coating time is 10 seconds to 20 seconds.

Pulsed plasma systems may also be used.

However, as will be appreciated by those skilled in the art, preferred conditions will vary depending on the size and geometry of the plasma chamber. This allows a person skilled in the art to advantageously change operating conditions, depending on the particular plasma chamber used.

The surface energy of the continuous coating can be controlled by careful selection of precursors and plasma processing conditions. Depending on the particular plasma polymer, the surface may be hydrophilic or hydrophobic.

Water contact angles greater than 90 degrees, more preferably greater than 105 degrees, in hydrophobic coatings have proven to be preferred. Surface energy of less than 35 dynes / cm, more preferably less than 30 dynes / cm, in hydrophobic coatings has proven to be desirable. In certain circumstances, the hydrophobic nature of the continuous coating may be very desirable, since the hydrophobic property may reduce the likelihood of damaging the assembly due to moisture.

In some situations, however, hydrophilic coatings may be desirable. For example, hydrophilic coatings may be desirable where additional coatings or labels (eg, barcodes) are applied to the continuous coating. It is generally easier to attach additional coatings to hydrophilic coatings. Water contact angles of preferably less than 70 degrees, more preferably 55 degrees, in hydrophilic coatings have proven to be preferred. Surface energy greater than 45 dynes / cm, more preferably greater than 50 dynes / cm, in hydrophilic coatings has proven to be desirable.

As used herein, "continuous" means that the coating is substantially free of defects. Possible defects include holes, gaps and breaks in the coating. Continuous coating can be achieved using a polymer polymerized with a plasma formed in place on the electrical or electronic optical assembly. Using the plasma polymerization method described below, continuous coatings can be formed on all surfaces in contact with the plasma gas. This may be of particular advantage when coating means with a high aspect ratio are typically found on an electrical or electro-optical assembly. Using a plasma polymerization method may also allow underhangs to be covered by the coating.

The continuous coating is usually 1 nm to 10 μm, preferably 1 nm to 5 μm, more preferably 5 nm to 500 nm, more preferably 100 nm to 300 nm, and more preferably 150 nm to 250 nm, eg, mean-average thickness of about 200 nm. The thickness of the continuous coating may be substantially uniform or may vary from point to point. In certain embodiments, the continuous coating may be deposited to conform to the three dimensional surface of the substrate, conductive tracks and components.

The continuous coating completely covers the surface of the substrate, the plurality of conductive tracks, and at least one of the at least one electrical or electronic optical component. Preferably, the coating encapsulates the exposed portions of the surface of the substrate, the plurality of conductive tracks and at least one of the at least one electrical or electronic optical component. Therefore, it may be desirable for the continuous coating to be a protective coating. The protective coating may conformally coat the surface of at least one of the substrate, the plurality of conductive tracks and the at least one electrical or electronic optical component. For the avoidance of doubt, as discussed below, reference to a coating that completely covers other means may take the same meaning as defined above.

The area of the electrical or electronic light assembly completely covered with a continuous coating may be, under some circumstances, a residual portion that cannot be coated, or a part of a large electrical or electronic light assembly.

Continuous coatings can minimize changes to the electrical and / or light performance of the assembly to which they are applied. For example, the inductance of the electrical circuit of the assembly can only be minimally affected by the coating. In some situations, this may have a very significant advantage over other protective coatings that typically significantly modify the properties of the circuit, which may require altered properties of the assembly caused by other coatings to be considered when the assembly is designed. . The coating of the present invention may eliminate this requirement in some situations.

If a very large degree of protection from the environment is required for the electrical or electro-optical assembly, additional successive coatings of polymerized polymers with plasma can be applied onto the initial successive coating. As such, the electrical or electro-optical assembly may further comprise a first additional continuous coating comprising a polymer polymerized with plasma, as defined above, which completely covers the continuous coating, and the first additional It may optionally include a second additional continuous coating comprising a polymer polymerized with plasma, as defined above, which completely covers the continuous coating. Furthermore, further continuous coatings of polymers polymerized with plasma as defined above, for example third to tenth continuous coatings, may be applied as needed. The plasma polymerized polymers used in each additional continuous coating may independently be the same or different from the polymer polymerized with the plasma of the initial continuous coating. Each additional continuous coating is typically deposited by the method used to deposit the continuous coating. The precise properties of the initial continuous coating and additional continuous coatings can be used to improve or optimize the performance required from the coated assembly. For example, it may be desirable to have a high hydrophobic coating as the top coating in order to achieve good resistance to moisture.

Plasma-polymerized coatings of the present invention may also be used to provide additional environmental protection to existing electrical or electro-optic assemblies that are coated with another protective coating. This may be advantageous in situations where an outer coating with water resistance is required. As such, the electrical or electro-optical assembly comprises an epoxy resin, acrylic deposited between at least a portion of the continuous coating of polymerized into plasma and at least a portion of the substrate, the plurality of conductive tracks and the at least one electrical or electro-optic component. It may further comprise a coating of resin, silicone resin or parylene. In certain embodiments, parylene coatings may be deposited by chemical vapor deposition methods.

As such, the electrical or electro-optical assembly may comprise a substrate comprising an insulating material, a plurality of conductive tracks present on at least one surface of the substrate, at least one electrical or electro-optical component connected to the at least one conductive track, at least a portion of the substrate. Coatings of epoxy resins, acrylic resins, silicone resins or parylenes (which may be deposited by conventional chemical vapor deposition methods), and continuous coatings (substrates, a plurality of conductive tracks, at least one electrical or electro-optical light Components and a plasma polymerized polymer that completely covers at least one surface of the coating of epoxy resin, acrylic resin, silicone resin or parylene).

Preferably, the coating of epoxy resin, acrylic resin, silicone resin or parylene is a protective coating. Such an arrangement may comprise an electrical or electronic optical assembly comprising a coating of epoxy resin, acrylic resin, silicone resin or parylene deposited on at least a portion of a substrate, a plurality of conductive tracks and at least one electrical or electronic optical component. , By applying to the coating method described herein.

Continuous coatings may be applied to electrical or electro-optical assemblies with halohydrocarbon surface finish coatings as described in WO 2008/102113 (incorporated herein by reference). As such, the electrical or electrooptic assembly may comprise a surface finish coating comprising (a) a continuous coating and (b) a halohydrocarbon polymer deposited between the substrate and the surface of at least one of the plurality of conductive tracks. And the surface finish coating covers at least a portion of the plurality of conductive tracks, and the at least one electrical or electro-optical component is connected to the at least one conductive track through the surface finish coating. Preferably, the surface finish coating comprises a fluorohydrocarbon polymer, more preferably a plasma polymerized fluorohydrocarbon polymer.

The electrical or electro-optical assembly also includes a substrate comprising an insulating material, a plurality of conductive tracks present on at least one surface of the substrate, at least one electrical or electro-optical component connected to the at least one conductive track, a plurality of conductive tracks. A surface finish coating comprising a halohydrocarbon polymer deposited on at least a portion, and a continuous coating (the surface of at least one of a substrate, a plurality of conductive tracks, at least one electrical or electro-optical component and a surface finish coating A continuous coating comprising a fully covered plasma polymerized polymer), wherein at least one electrical or electro-optical component is connected to the at least one conductive track through the surface finish coating.

Preferably, the electrical or electro-optical component is connected to at least one conductive track via a solder joint, weld joint or wire-bond joint, and the solder joint, weld joint or wire-bond The seam is located adjacent to the surface finish coating.

When the assembly comprises a coating or surface finish coating of epoxy resin, acrylic resin, or silicone resin, the assembly details an assembly with a coating of epoxy resin, acrylic resin, or silicone resin or a suitable surface finish coating. By applying to a conventional coating method. Similarly, further continuous coatings are typically deposited by the coating method described above.

An additional advantage of plasma polymerized coatings is that plasma polymerized coatings can be readily facilitated by a plasma removal process in some situations. The plasma removal process may include plasma etching the coating to expose a surface located below the electrical or electro-optical assembly. The coating may have a thickness of about 200 nm. Conventional protective coatings applied to electrical or electro-optical assemblies using methods known in the art typically have a thickness of 25 to 200 μm. Removal of protective coatings is currently time consuming and expensive to use plasma etching due to the large volume of material being removed. As such, as defined above, the electrical or electro-optical assembly may be subjected to a plasma removal process. This plasma removal process typically removes substantially all of the continuous coating. If present, it will typically be possible to substantially eliminate both further continuous coatings and / or surface finish coatings. The plasma removal process typically involves chemically and / or physically impacting the surface of the coating to locate the plasma chamber in an electrical or electro-optical assembly, and to remove the material and gradually etch it back to the underlying underlying surface. Introducing a reactive gas plasma to be applied.

Such a process is fast and inexpensive, which may have advantages. The electrical or electro-optical assembly from which the coating has been removed may be reprocessed, typically by adding additional components or by replacing existing components. Alternatively, the connection between the conductive tracks and the components can be reprocessed if the connection is damaged in use.

Upon completion of the reprocessing, the alternative continuous coating comprising the polymer is prepared by plasma polymerization, in which the coating completely covers the surface of at least one of the substrate, the plurality of conductive tracks and the at least one electrical or electronic optical component. May be optionally deposited. As such, in some situations, a damaged electrical or electronic light assembly can be easily repaired.

A further advantage of the plasma polymerized coating is that there may be no need to remove the coating before the plasma polymerized coating is retreated. This may allow soldering through the coating in some circumstances. In some situations, an initial coating, first and second additional coatings of electrical or electronic optical assemblies that may be present, and / or also for forming solder joints between the additional electrical or electronic optical components and the at least one conductive track. Soldering may be possible through the surface finish coating. The braze joint may be located adjacent to the continuous coating, the first and second additional coatings that may be present and / or the surface finish coating.

Further applications include removal of the surface finish coating as described above by a plasma removal process, followed by deposition of polymer polymerized into the plasma as described above. Another application includes the removal of the surface finish coating as described above by a plasma removal process, followed by connecting the electrical or electro-optical components to the conductive tracks, and then depositing the polymer polymerized into the plasma as described above. .

The electrical or electronic light assembly may comprise a plurality of conductive tracks, which may be electrically conductive tracks or light conductive tracks.

The electrically conductive tracks comprise a suitable electrically conductive material. Preferably, the electrically conductive track comprises gold, tungsten, copper, silver, aluminum, doped regions of the semiconductor substrate, conductive polymers and / or conductive inks. More preferably, the electrically conductive tracks comprise gold, tungsten, copper, silver or aluminum.

The problem of suitable shape and configuration for the conductive tracks can be selected by one of ordinary skill in the art regarding the particular assembly.

Typically, an electrically conductive track is attached to the surface of the substrate along the entire length of the track. Alternatively, the electrically conductive track can be attached to the substrate at two or more points. For example, the electrically conductive track can be a wire attached to the substrate at two or more points but not along the entire length of the track.

Electrically conductive tracks are typically formed on a substrate using suitable methods known to those skilled in the art. In a preferred method, electrically conductive tracks are formed on the substrate using a "subtraction" technique. Typically in this way, the metal layer (eg copper foil, aluminum foil, etc.) is adhered to the surface of the substrate, after which unwanted portions of the metal layer are removed leaving the desired conductive tracks. Unwanted portions of the metal layer are typically removed from the substrate by chemical etching or photo-etching, milling. In an alternative preferred method, conductive tracks are formed on a substrate using " additional " techniques such as electroplating, deposition using, for example, reverse masks, and / or geometrically controlled deposition processes. Alternatively, the substrate may be a silicon die or wafer with regions typically doped as conductive tracks.

The light conducting track typically comprises a suitable light conducting material. Preferably, the light conducting track is an optical waveguide typically comprising a light transmitting material whose change in refractive index is used to transmit electromagnetic radiation through a desired path. An optical waveguide can be produced, for example, by applying a cladding or boundary layer to a light transmitting material, the cladding or boundary layer being composed of materials of different refractive indices. Alternatively, the waveguide can be produced by doping or modifying the light transmitting material to create regions of variable refractive index. Therefore, the waveguide may be standalone components or means integrated into the substrate. Typical light transmitting materials are glass, doped glass and plastic.

The plurality of conductive tracks may comprise only electrically conductive tracks, only light conductive tracks, or a mixture of electrically conductive tracks and light conductive tracks. Where more than one electrically conductive track is present, each track may be composed of the same material as defined above, and / or may have the same shape, or alternatively may have various track materials and / or track shapes. have. If there is more than one optically conductive track, each track may be composed of the same material as defined above, and / or may have the same shape, or alternatively may have various track materials and / or track shapes. have.

The plurality of conductive tracks may further comprise at least one external contact means. The continuous coating preferably completely covers at least one external contact means.

The precise nature of the external contact means may depend on the properties of the assembly and the device for which contact is required. Suitable contacts can be generally selected by one of ordinary skill in the art. Typically, the external contact means makes electrical or optical contact. The external contact means can be part of a plurality of conductive tracks. Alternatively, the external contact means can be an additional component electrically or optically connected to the at least one conductive track.

The plasma polymerized coating allows the electrical connection to be realized without (a) external contact means, preferably between electrical contacts and (b) corresponding contacts on the external device, without prior removal of the continuous coating. Similarly, a plasma polymerized coating may allow optical connections to be realized without (a) external contact means, preferably between the optical contacts and (b) corresponding contacts on the external device, without prior removal of the continuous coating. Therefore, it may not be necessary in any case to mask the external contact means of the assembly prior to forming the plasma polymerized coating. In some situations, this may be advantageous because masking of the external contact means can be time consuming and expensive.

The electrical or electrooptic assembly may comprise a substrate, which may include an insulating material. The substrate typically comprises an insulating material suitable to prevent the substrate from shorting to the circuit of the electrical or electronic optical assembly. As such, in the electrical assembly, the substrate is preferably electrically insulated. In the electro-optical assembly, the substrate is preferably electrically insulated and optically isolated.

The substrate is preferably an epoxy laminated material, an artificial resin bonded paper, an epoxy resin bonded glass structure (ERBGH), a synthetic epoxy material (CEM), PTFE (Teflon), or other polymeric material, phenolic cotton paper (phenolic) cotton paper, silicone, glass, ceramic, paper, cardboard, materials based on natural and / or synthetic wood, and / or other suitable fabrics. The substrate optionally further comprises a flame retardant material, typically Flame Retardant 2 (FR-2) and / or Flame Retardant 4 (FR-4). The substrate may comprise a single layer of insulating material or multiple layers of the same or different insulating materials. The substrate may be a board of a printed circuit board (PCB) composed of one of the materials listed above.

The electrical or electron light assembly comprises at least one electrical or electron light component.

The electrical component can be a suitable circuit element of the electrical assembly. Preferably, the electrical component is a resistor, capacitor, transistor, diode, amplifier, antenna or oscillator. Suitable numbers and / or combinations of electrical components can be connected to the electrical assembly.

The electrical component is preferably connected to the electrically conductive track via an adhesive. The adhesive is preferably a soldered joint, a welded joint, a wire-bond joint, a conductive adhesive joint, a crimp connection, or a press-fit joint. Suitable soldering, welding, wire-bonding, conductive adhesives and press fit techniques are known to those skilled in the art to form adhesives. More preferably the adhesive is a solder joint, a weld joint or a wire-bond joint, with the solder joint most preferred.

The electronic light component may be an electromagnetic signal, ie a component in which the optical signal is electrically controlled in active switches, filters, modulators, amplifiers, and switchable elements. Alternatively, the electronic light component may be an electromagnetic signal, ie a component that converts the optical signal into an electronic signal or vice versa, for example light emitters, photo detectors and detector arrays. Thus, the electronic optical component is preferably a light emitting diode (LED), a laser LED, a photodiode, a phototransistor, a photomultiplier, or a photoresistor.

As will be appreciated by those skilled in the art, the electronic light component may have electrical input / output and light input / output. The electrical inputs / outputs are connected to an electrically conductive track, but preferably via an adhesive as defined above. The light input / output is connected to the light conducting track, preferably via an adhesive.

The assembly may optionally further include an optical component. The light component may be a passive component. Passive components may include, for example, couplers, splitters, Y-splitters, star couplers, fiber and optical switches. The optical component is typically connected to a light conductive track, preferably via an adhesive. Optical components and adhesives, where present, are typically completely covered by a continuous coating.

Optical connectivity can be achieved through active or passive mechanical structures that optically align components and conductive tracks and mechanically hold them in place. Alternatively, the optical connection can be implemented using an adhesive that optionally has a selected / controlled refractive index. Alternatively, optical connections can be created by joining components and conductive tracks together. Alternatively, the refractive index of the material may be modified, for example, by doping the new material to create a new connection. Alternatively, adding a suitable material in place can be applied to create a new optical geometry.

In one preferred embodiment, the electrical assembly is connected to a substrate comprising an insulating material, to a plurality of electrically conductive tracks present on at least one surface of the substrate, to at least one electrically conductive track, preferably as defined above. At least one electrical component connected by the same at least one adhesive, and a plasma completely covering the surface of at least one of the substrate, the plurality of electrically conductive tracks, at least one electrical component, and at least one adhesive, if present Continuous coatings comprising fluoropolymers polymerized with; More preferably, the electrically conductive tracks comprise at least one external contact means, which is typically at least one electrical contact, wherein the at least one external contact means is also completely covered by a continuous coating.

In another preferred embodiment, a printed circuit board comprises a substrate comprising an insulating material, a plurality of electrically conductive tracks present on at least one surface of the substrate, at least one solder joint, a weld joint or a wire-bond joint. At least one electrical component connected to the at least one electrically conductive track by at least one of a substrate, a plurality of electrically conductive tracks, at least one electrical component and at least one solder joint, a weld joint or a wire-bond joint And a continuous coating comprising a fluoropolymer polymerized with plasma that completely covers the surface of the substrate.

In another preferred embodiment, a printed circuit board comprises a substrate comprising an insulating material, a plurality of electrically conductive tracks including at least one external contact means present on at least one surface of the substrate, at least one solder joint, a weld joint At least one electrical component connected to the at least one electrically conductive track by means or a wire-bond joint, and a substrate, a plurality of electrically conductive tracks, at least one external contact means, at least one electrical component and at least one solder And a continuous coating comprising a plasma polymerized fluoropolymer that completely covers the surface of at least one of the seam, welded seam or wire-bonded seam.

Continuously polymerized polymer coatings can be used to coat electrical or electro-optical components. In this way, the electrical or electronic optical component can be completely covered with a continuous coating comprising a polymer polymerized with plasma as defined above for the electrical or electronic optical assembly. Such coated components can be manufactured by applying the components to the coating method described above. Plasma polymerized polymer coatings can provide electrical or electro-optical components with good protection from the environment, thereby making them particularly useful in the case of expensive components. A preferred embodiment is an electrical component completely covered with a continuous coating comprising a fluoropolymer polymerized with plasma.

The coated electrical or electro-optical components can be connected to at least one conductive track of the electrical or optical assembly, typically in the case of electrical components by soldering or wire-bonding, without prior removal of the continuous coating. In this case, all of the continuous coating can remain substantially intact and provide protection from a post-installation environment. Alternatively, the coating may be removed by a plasma removal process prior to installation of the assembly.

In certain embodiments, the polymer polymerized with plasma as described above may be used to protectively coat an electrical or electrooptic assembly or an electrical or electrooptic component.

Aspects of the present invention will now be described with respect to the embodiments shown in the accompanying drawings, and examples, wherein like reference numerals refer to the same or similar components.

Drawing Description

1A shows the results of X-ray photoelectron spectroscopy analysis of fluoropolymers polymerized with plasma. This shows that the fluoropolymer polymerized with plasma contains high proportions of CF ₃ , CF and C-CF residues, indicating a high degree of branching and cross-linking. FIG. 1B shows the results of X-ray photoelectron spectroscopic analysis of fluoropolymers obtained by standard polymerization techniques, ie, commercially available PTFE. This shows that fluoropolymers obtained by standard polymerization techniques contain mostly negligible proportions of CF ₃ , CF and C-CF residues and CF ₂ residues, indicating a very low degree of branching and crosslinking. The way in which these results were obtained is described in Example 1.

FIG. 2A shows an electron microscope image of the fluoropolymer coating polymerized with the plasma of the present invention and the smooth physical properties of the coating. 2B shows an image of the PTFE coating under an electron microscope, where the PTFE coating is deposited by standard polymerization techniques with a structure where the fibrils are clearly visible.

3 shows an electrical assembly, wherein the electrical assembly comprises a substrate 1 comprising an insulating material, a plurality of conductive tracks 2 present on at least one surface of the substrate 1, at least one conductive track ( Electrical components 3 connected to 2), and a continuous coating 4, the continuous coating comprising: a substrate 1, a plurality of conductive tracks 2 and an electrical component 3; A polymer polymerized with plasma that completely covers at least one surface.

4 shows an electrical assembly, wherein the electrical assembly is formed by a substrate 1 comprising an insulating material, a plurality of conductive tracks 2, an adhesive 5 present on at least one surface of the substrate 1. Electrical components (3) connected to at least one conductive track (2), and a continuous coating (4), said continuous coating comprising a substrate (1), a plurality of conductive tracks (2), electrical It comprises a plasma polymerized polymer which completely covers the surface of at least one of the components 3, the adhesive 5.

5 shows an electrical assembly, wherein the electrical assembly comprises a substrate 1 comprising an insulating material, a plurality of conductive tracks 2 present on at least one surface of the substrate 1, and at least one conductive track ( A plasma completely covering the surface of at least one of the electrical components 3, the continuous coating 4 (substrate 1, the plurality of conductive tracks 2, and the electrical components 3 connected to 2). To a polymer), and a first further continuous coating 7 (including a plasma polymerized polymer completely covering the continuous coating 4).

6 shows an electrical assembly, wherein the electrical assembly comprises a substrate 1 comprising an insulating material, a plurality of conductive tracks 2 present on at least one surface of the substrate 1, at least one conductive track ( A plasma completely covering the surface of at least one of the electrical components 3, the continuous coating 4 (substrate 1, the plurality of conductive tracks 2, and the electrical components 3 connected to 2). Polymerized with a polymer), and an epoxy resin disposed between at least a portion of the continuous coating 4 and at least a portion of the substrate 1, the plurality of conductive tracks 2 and the electrical components 3, Coating 8 which is an acrylic resin or a silicone resin.

FIG. 7 shows an electrical assembly, wherein the electrical assembly is formed by a substrate 1 comprising an insulating material, a plurality of conductive tracks 2, an adhesive 5 present on at least one surface of the substrate 1. Of electrical component 3, continuous coating 4 (substrate 1, a plurality of conductive tracks 2, electrical components 3 and adhesive 5) connected to at least one conductive track 2. And a surface finish coating (6) comprising halohydrocarbon, wherein the halohydrocarbon comprises a continuous coating (4) and a substrate ( 1) and at least one surface of the plurality of conductive tracks 2. The electrical components 3 are connected to the conductive track 2 via the surface finish coating 6 via the adhesive 5 adjacent the surface finish coating 5.

8 shows an electron light assembly wherein the electron light assembly comprises a substrate 1 comprising an insulating material, a plurality of conductive tracks 17, 18 present on at least one surface of the substrate 1, at least one Electronic light components 19 connected to conductive tracks 17, 18, and a continuous coating 4 (substrate 1, a plurality of conductive tracks 17, 18, and electro-electronic light components ( 19) comprising a polymer polymerized with a plasma completely covering the surface of at least one of. Conductive track 17 is an optically conductive track, for example an optical fiber. Conductive track 18 is an electrically conductive track. The refractive index of the coating 20 region is controlled by the light interconnect 21.

9 shows the electrical component 15 completely covered with a continuous coating comprising a polymer 16 polymerized with plasma.

10 shows an example of an apparatus that can be used to form the polymerized polymer coating with the plasma of the present invention. In this example, the reactor 9 has a chamber 10 connected to a vacuum system 11 and an energy source 12. The precursor compound is ionized or decomposed or ionized and decomposed by the plasma to form an active species 13, and then the surface of the assembly 14 to form a continuous, plasma polymerized polymer coating. Reacts to

11A, 11B, and 11C are flowcharts illustrating specific embodiments of the method described above.

Yes

Example 1- With plasma  Polymerized Fluorohydrocarbon XPS  analysis

The epoxy laminated substrate is coated with fluorohydrocarbons polymerized with plasma. This stack is cut to form a sample size of about 1 square cm and introduced into the sample chamber of a Thermo-Scientific ESCALAB 250 X-Ray Photoelectron Spectrometer.

The chamber is pumped down to an operating pressure of 10 ^-10 Torr, after which the sample is transferred to the analysis chamber. Monochromatic X-ray beams are incident on the surface, and photoelectrons emitted by the sample are collected and analyzed.

A broad signal scan is processed to capture all devices on the surface, and then a higher resolution scan of the C1s peak is processed to determine the microstructure of the peak and the chemical structure of the sample.

The results are shown in Figure 1a.

Example 2-Coating Coated Assembly

The assembly is coated in Runs 1-10 using the precursor and plasma polymerization conditions shown in Table 1 below.

Example 3 - plasma  Removal process

An electrical assembly coated with plasma polymerized fluorohydrocarbons is introduced into the plasma chamber. The chamber is pumped down to 250 mTorr operating pressure and oxygen gas is introduced at a flow rate of 2500 sccm. The gas is allowed to flow through the chamber for 30 seconds after which the plasma generator is switched on at a frequency of 40 kHz and an output of 3 kW. The assembly is exposed to the active plasma for a time of 5 minutes, after which the plasma generator is switched off and the chamber returns back to atmospheric pressure.

The assembly is removed from the plasma chamber and the removal of the plasma polymer coating is verified using Bruker FTIR spectroscopy. The absence of C-F-specific stretching peaks at 1250 nm indicates that the fluoropolymer was completely removed.

Claims (29)

Substrates including insulating materials,
A plurality of conductive tracks present on at least one surface of the substrate,
At least one electrical or electro-optical component connected to at least one conductive track, and
An electrical or electro-optical assembly comprising a continuous coating comprising a polymer polymerized with a plasma that completely covers the substrate, the plurality of conductive tracks and at least one surface of the at least one electrical or electronic optical component. The method according to claim 1,
The plasma polymerized polymer is an electric or electro-optical assembly, characterized in that the hydrocarbon or halohydrocarbon polymerized with plasma. The method according to claim 1 or 2,
Wherein said polymer polymerized with plasma is fluorohydrocarbon polymerized with plasma. The method according to any one of claims 1 to 3,
The fluorohydrocarbons polymerized by plasma are perfluoroalkanes, perfluoroalkenes, perfluoroalkynes, fluoroalkanes, fluoroalkenes, fluoroalkynes, and fluoroalkynes. Fluoroacrylates, fluoroesters, fluorosilanes, fluorochloroalkanes, fluorochloroalkenes, fluorochloroalkynes, fluorochloroacrylates, fluorochloroacrylates An electrical or electro-optical assembly characterized by being obtained by at least one precursor compound polymerized with plasma, selected from fluorochloroesters and fluorochlorosilanes. The method according to any one of claims 1 to 4,
The at least one electrical or electro-optical component is an electrical component,
Said at least one conductive track is an electrically conductive track. The method according to claim 5,
The electrical component is connected to the at least one conductive track by at least one adhesive,
The continuous coating completely covers the at least one adhesive. The method of claim 6,
Wherein said at least one adhesive is a soldered joint, a welded joint, a wire-bond joint, a conductive adhesive joint, a crimp connection, or a press fit joint. The method of claim 7,
Wherein said at least one adhesive is a soldered joint, a welded joint or a wire-bonded joint. The method according to any one of claims 1 to 4,
The at least one electrical or electronic optical component is an electronic optical component,
The at least one conductive track is an electrically conductive track or an optically conductive track. The method according to any one of claims 1 to 9,
The plurality of conductive tracks further comprises at least one external contact means,
The continuous coating completely covers the at least one external contact means. The method of claim 10,
Said at least one external contact means being an electrical contact. The method of claim 10,
Said at least one external contact means being an optical contact. The method according to any one of claims 1 to 12,
The electrical or electronic light assembly further comprising an optical component connected to a light conductive track. The method according to any one of claims 1 to 13,
The electrical or electro-optical assembly,
Further comprising a first additional continuous coating comprising a polymer polymerized with a plasma as defined in any one of claims 1 to 4 completely covering the continuous coating,
Optionally comprising a second further continuous coating comprising a polymer polymerized with a plasma as defined in any one of claims 1 to 4 completely covering the first further continuous coating. Electronic optical assembly. The method according to any one of claims 1 to 14,
The electrical or electro-optical assembly,
A coating of epoxy resin, acrylic resin, silicone resin or parylene deposited between at least a portion of the continuous coating of polymerized into plasma and at least a portion of the substrate, the plurality of conductive tracks, and at least one electrical or optical component An electrical or electrooptic assembly, further comprising water. The method according to any one of claims 1 to 15,
The electrical or electro-optical assembly,
a surface finish coating comprising (a) the continuous coating and (b) a halohydrocarbon polymer deposited between the substrate and at least one surface of the plurality of conductive tracks,
The surface finish coating covers at least a portion of the plurality of conductive tracks,
The at least one electrical or electro-optical component is connected to the at least one conductive track through the surface finish coating. 18. The method of claim 16,
10. The electrical or electro-optical assembly of claim 8, wherein the soldered joint, the welded joint or the wire-bond joint is located adjacent to the surface finish coating. The method according to any one of claims 1 to 17,
The electrical or electronic optical assembly is a printed circuit board. A method of manufacturing an electrical or electronic optical assembly according to any one of claims 1 to 18,
(a) providing an electrical or electronic optical assembly comprising a substrate comprising an insulating material, a plurality of conductive tracks present on at least one surface of the substrate, and at least one electrical or electronic optical component connected to the at least one conductive track. Steps, and
(b) a continuous coating comprising a polymer as defined in any one of claims 1 to 3 completely covering the surface of at least one of the substrate, the plurality of conductive tracks and the at least one electrical or electro-optical component. A method of manufacturing an electrical or electronic optical assembly comprising depositing water using plasma polymerization. The method of claim 19,
And depositing using the plasma polymerization comprises at least one precursor compound polymerized with plasma as defined in claim 4. An electric or electrooptic assembly obtainable by the method of manufacturing an electric or electrooptic assembly according to claim 19 or 20. An electrical or electro-optical component completely covered with a continuous coating comprising a polymer polymerized with a plasma as defined in claim 1. (a) continuous coatings and first and second further continuous coatings and / or surface finish coatings, where the first and second additional continuous coatings and / or surface finish coatings are present. Applying an electrical or electro-optical assembly according to any one of claims 1 to 14, 16 to 18 or 21 to the plasma removal process so that it is removed, and then
(b) optionally reprocessing the final electrical or electronic light assembly, and then
(c) selectively depositing a continuous, alternative coating, using plasma polymerization, comprising a polymer completely covering the surface of the substrate, the plurality of conductive tracks, and at least one of the at least one electrical or electronic optical component. How to. Continuous coating of an electrical or electro-optical assembly according to any one of claims 1 to 14, 16 to 18 or 21, and first and second further continuous coatings and / or surface finish coatings (the first and Soldering through a second additional continuous coating and / or surface finish coating, if any) to form a solder joint between the additional electrical or electro-optical component and the at least one conductive track,
The solder joint is a continuous coating and the first and second further continuous coatings and / or surface finish coatings (where the first and second further continuous coatings and / or surface finish coatings are present If adjacent to). (a) a surface finish coating comprising a substrate comprising an insulating material, a plurality of conductive tracks present on at least one surface of the substrate, a halohydrocarbon polymer covering at least a portion of the plurality of conductive tracks, and the surface finish Applying an electrical or electro-optical assembly comprising at least one electrical or electro-optical component connected to at least one conductive track through a coating in a plasma removal process, whereby the surface finish coating is removed.
(b) a continuous coating comprising a polymer as defined in any of claims 1 to 4 completely covering the surface of the substrate, the plurality of conductive tracks and the at least one electrical or electro-optical component. And depositing using plasma polymerization. (a) an electrical comprising a substrate comprising an insulating material, a plurality of conductive tracks present on at least one surface of the substrate, and a surface finish coating comprising a halohydrocarbon polymer covering at least a portion of the plurality of conductive tracks; Applying an electro-optical assembly to a plasma removal process to remove the surface finish coating, and then
(b) connecting the electrical or electro-optical component to at least one conductive track, then
(c) a continuous coating comprising a polymer as defined in any one of claims 1 to 4 completely covering the surface of at least one of the substrate, the plurality of conductive tracks and the at least one electrical or electro-optical component. And depositing using plasma polymerization. An electrical or electrooptic assembly having a protective coating comprising a polymer polymerized with a plasma as defined in claim 1. Use of a plasma polymerized polymer as defined in claim 1 as a protective coating for an electrical or electrooptic assembly. A method of protectively coating an electrical or electronic optical assembly, comprising depositing a polymer as defined in claim 1 using plasma polymerization.

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