TW202401560A - Methods of etching conductive features - Google Patents

Abstract

A method of making a device patterned with one or more electrically conductive features includes depositing a conductive material layer over an electrically insulating surface of a substrate, depositing an anti-corrosive material layer over the conductive material layer, and depositing an etch-resist material layer over the anti-corrosive material layer. The etch-resist material layer may be deposited over the anti-corrosive material layer, and the anti-corrosive material layer forming a bi-component etch mask in a pattern resulting in covered portions of the conductive material layer and exposed portions of the conductive material layer, the covered portions being positioned at locations corresponding to one or more conductive features of the device. A wet-etch process is performed to remove the exposed portions of the conductive material layer from the electrically insulating substrate, and the bi-component etch mask is removed to expose the remaining conductive material. Systems and devices relate to devices with patterned features.

Description

Methods of Etching Conductive Features

The present invention relates to a method of manufacturing a device with patterned conductive features and related devices and systems. [Cross-reference to related applications] This application claims the following rights and interests: U.S. Provisional Application No. 62/432,710, titled "Method of Etching Conductive Lines," filed on December 12, 2016, which is incorporated by reference in its entirety.

The manufacture of various electronic devices and electronic components requires the fabrication of patterned layers on substrates. For example, microchips, printed circuit boards, solar cells, electronic displays (such as liquid crystal displays, organic light-emitting diode displays, and quantum dot electroluminescent displays), and various other electrical or optical devices and components can be made from substrates The support consists of multiple overlapping patterned layers of different materials. Such a patterned layer can be fabricated on a substrate by applying a layer of unpatterned material to the substrate, preparing a resist mask over the layer, and performing an etching process to remove the layer that is not masked by the resist. This is done by covering the portion, thereby forming a patterned layer on the substrate.

In one illustrative example that may be used to manufacture, for example, a printed circuit board (PCB) or other electronic component, a conductive metal layer is applied to an electrically insulating surface of a substrate (or equivalently, a conductive layer is formed on the electrically insulating surface of a substrate) , applying a resist mask to (or forming) a conductive layer, and performing an etching process to remove portions of the conductive layer not covered by the resist mask, thereby forming a patterned conductive layer on the electrically insulating surface of the substrate layer. The patterned conductive layer so formed may include one or more conductive features of conductive material on the electrically insulating surface of the substrate, which may further include, for example, lines, circles, squares, and other shapes. In some cases, the etching process used to form such a patterned conductive layer may be a wet etching process, whereby a liquid etching material interacts with the conductive layer to remove the conductive layer from the electrically insulating surface of the substrate. For example, such a wet etching process may be a wet "chemical" etching process.

A common feature of wet etching is "undercutting," which in a typical example of etching a conductive layer refers to the removal of material from the conductive layer beneath the etching mask. Such undercutting can reduce the conductivity of the conductive layer by reducing the feature width perpendicular to the direction of current flow relative to the corresponding width of the etch mask. As a result, the conductivity may drop below a desired level. Such reduction in conductivity due to undercutting may be particularly evident with relatively small feature widths, such as feature widths below about 60 μm. This undercut phenomenon can also give conductive features sloping or non-planar "sidewalls." As used herein, "sidewall" refers to a side surface of a feature, such as a wall on the side of the feature that extends downward from the top of the feature proximate the etch mask to the bottom of the feature proximate the substrate. In some cases, features associated with such undercuts may have sloped or non-planar sidewalls such that the width near the top of the feature (near the etch mask) is less than the width of the bottom of the feature (near the substrate). Since a certain minimum feature width at the top of a feature may be desired, such as to achieve a desired conductivity or to achieve a desired electrical frequency response, such an undercut may have an effect on at least one of the minimum feature width or the minimum feature-to-feature spacing. One imposes a lower limit, thereby limiting the feature density that can be provided on the substrate.

For applications other than patterning of conductive metal lines in manufacturing PCBs, undercutting may be undesirable. For example, similar considerations described above for PCBs may also apply to other applications utilizing metal wires to carry current and/or electrical signals, such as in the manufacture of microchips, electronic displays, or solar cells. In another example, other considerations may apply to applications utilizing non-metallic patterned layers (eg, optical coatings or insulating layers) in the fabrication of electronic or optical devices or components, where substantially vertical sidewalls are desired. of.

When forming patterned layers on substrates for fabricating electronic and/or optical devices or electronic and/or optical components, improved techniques exist to mitigate (e.g., reduce or eliminate) undercutting on features formed using wet etching procedures. needs.

In conventional processing, the above-mentioned etching mask is formed by applying a blanket coating of a photosensitive material (usually a UV light-sensitive material) to the substrate, which is converted into an etching mask after patterned exposure and subsequent processing. Mask. Such subsequent processing typically involves removal of the photosensitive material (eg, during a development step) to form an etch mask pattern on the substrate. In many cases, such as, but not limited to, when an etch mask is used to pattern metal layers of a PCB, the etch mask covers less than 50% of the substrate surface, and the removed photosensitive material is discarded as waste. In many cases, removal of light-sensitive materials requires cleaning the substrate in a liquid (eg, developer), and the liquid used to perform such cleaning is discarded as waste. In many cases, such as, but not limited to, when an etching mask is used to pattern the metal layers of a PCB, the light-sensitive material is prepared on a carrier sheet and then transferred from the carrier sheet to the substrate via lamination, and in such Discard the carrier piece as waste after transfer. When manufacturing electronic and/or optical devices and/or components, it is often desirable to reduce waste. One way to reduce such waste is to apply the etch mask directly to the substrate in the desired pattern using pressureless printing (such as inkjet printing) to deliver the liquid etch mask ink to the substrate in the desired pattern and then The liquid coating is subsequently processed (eg, via drying and/or baking) to form a completed etch mask. However, inks delivered by such pressureless printing methods generally do not adhere well to substrate surfaces used in the fabrication of optical and/or electrical components and/or devices, and such inks may remain on such substrates. Diffusion and/or displacement in an uncontrolled manner, causing phenomena such as aggregation, agglomeration and dot enlargement. As a result, etched masks resulting from such pressureless printing methods can exhibit reduced resolution, lack of detail, inconsistent patterned line widths, poor line edge smoothness, connections between features that are intended to be separated, and that are intended to be continuous. Interruptions in Characteristics.

Where pressureless printing is used to prepare etch masks as described above, there is a need to mitigate (eg, reduce or eliminate) such uncontrolled diffusion and/or displacement of deposited liquid etch mask ink on the substrate surface. needs.

In one exemplary aspect of the invention, a method of fabricating a device patterned with one or more conductive features includes depositing a layer of conductive material over an electrically insulating surface of a substrate and depositing a corrosion-resistant material over the layer of conductive material layer, and depositing a layer of resist material over the layer of corrosion resistant material. A resist material layer is deposited on top of the anti-corrosion material layer. The resist material layer and the anti-corrosion material layer are patterned to form a two-component etching mask to obtain the covered portion of the conductive material layer and the conductive material. The exposed portion of the layer, the covered portion being disposed at a location corresponding to one or more conductive features of the device. A wet etching process is performed to remove the exposed portion of the electrically insulating substrate, and the two-component etch mask is removed to expose remaining conductive material of the covered portion of the layer of conductive material, thereby forming one or more components of the device conductive characteristics.

In another illustrative aspect of the invention, an apparatus for fabricating a device patterned with conductive features includes a first deposition module configured to deposit over a layer of conductive material over an electrically insulating surface of a substrate a layer of corrosion-resistant material; a second deposition module configured to deposit a layer of resist material over the corrosion-resistant material; and a wet etching module configured to etch the conductive material layer of the substrate.

In yet another illustrative aspect of the invention, a device patterned with conductive features includes a substrate having an electrically insulating surface and conductive features disposed on the electrically insulating surface. The conductive feature includes a height (c) measured in a direction normal to the electrically insulating surface; a first width (a) measured at the electrically insulating surface; and a height (c) along the conductive feature, and A second width (b) measured at the end of the conductive feature opposite the electrically insulating surface. The value of half the difference between the first width (a) and the second width (b) divided by the height (c) is at least 2 (that is, [a-b]/c ≥ 2).

In yet another illustrative aspect of the invention, a method includes applying a first liquid composition including a first reactive component to a metallic surface to form a primer layer, and printing on the primer layer by a pressureless printing method. A second liquid composition containing a second reactive component is imagewise printed on the paint layer to produce an etching mask according to a predetermined pattern. When droplets of the second liquid composition contact the primer layer, the second reactive component chemically reacts with the first reactive component to stop the movement of the droplets.

Part of other objects, features, and/or other advantages will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention and/or claims. At least some of these objects and advantages may be realized and obtained by means of the elements and combinations particularly pointed out in the appended claims.

The foregoing general description and the following detailed description are illustrative and explanatory only, and do not limit the claimed scope; rather, these claimed claims shall be entitled to the full scope thereof, including equivalents.

In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the invention. However, one skilled in the art will understand that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail in order to avoid obscuring the present invention.

Microchips, printed circuit boards, solar cells, electronic displays (such as, but not limited to, for example, liquid crystal displays, organic light emitting diode displays, and quantum dot electroluminescent displays), and various other electrical or optical devices and components can be made from It consists of a plurality of overlapping layers of different materials, including patterned layers, supported by a substrate. Various illustrative embodiments of the present invention contemplate methods and apparatus for forming patterned layers on substrates for use in electrical and/or optical devices and/or components. As used herein, "device layer" shall refer to a material in its final form (which may in some cases be patterned) as a layer included in a completed optical and/or electronic device and/or component layer, wherein further, "patterned device layer" shall refer to such layer after being patterned, and "unpatterned device layer" shall refer to such layer before being patterned. Such layers. For example, various illustrative embodiments contemplate a patterned device layer of conductive material that includes a set of conductive lines, such as may be fabricated on a substrate as part of manufacturing a printed circuit board (PCB) or other electronic component. According to specific examples of the present invention, an unpatterned device layer on a substrate (such as, but not limited to, a conductive layer of copper or other conductive material overlying an electrically insulating surface of the substrate) may be coated with an undercut-reduced coating that includes -reducing) material that has the effect of reducing undercutting during a wet etch process used to remove device layer material exposed through an etch mask. For example, the undercut reduction material may be a corrosion-resistant material, which may include materials that exhibit corrosion-resistant properties relative to device layer materials. Such corrosion-resistant materials may include polymers, organic materials, inorganic materials, Schiff bases, or other materials, such as those disclosed in International Patent Application Publication Nos. WO2016/193978 A2 and WO2016/025949 A1, each of which The entire contents of one are incorporated herein by reference. The corrosion-resistant material may be blanket-formed or blanket-deposited, or patterned or pattern-deposited over the unpatterned device layer. In various illustrative embodiments, the terms corrosion-resistant material and undercut-reducing material may be used interchangeably.

Various illustrative embodiments of the present invention contemplate forming a primer layer including an undercut reducing material over an unpatterned device layer on a substrate, and then forming a patterned layer of resist material over the primer layer. An etching mask is formed on the substrate. Other illustrative embodiments of the present invention contemplate forming a patterned layer of a mixture of undercut reducing material and resist material on a substrate over an unpatterned device layer on the substrate. The etch mask is formed over the top, eliminating the need to form a separate layer containing undercut reduction material, such as a primer layer. In an illustrative embodiment, a primer layer containing an undercut reducing material is formed over an unpatterned device layer on a substrate, and then a liquid resist ink is applied or deposited in a pattern over the primer layer, followed by Subsequent processing (such as by drying or baking the ink to form a solid patterned layer of resist material) converts the liquid ink into an etch mask to form an etch mask over the primer layer, where such liquid resist The ink may contain materials that interact with the primer layer. For example, a liquid resist ink may undergo a chemical reaction upon contact with the primer layer that limits the displacement or diffusion of the ink on the primer surface, such as via a chemical reaction. In another example, liquid resist ink may be applied to a surface in the form of droplets delivered by an inkjet nozzle, and upon contact with the primer surface, such droplets may be effectively immobilized or "Freezes" in place so that further displacement or spreading of ink droplets on the primer surface is greatly reduced or completely stopped, as described in International Publication Nos. WO2016/193978 A2 and WO2016/025949 A1, the entire contents of each of which Incorporated herein by reference. In illustrative embodiments, limiting the spread of the resist ink on the primer surface, such as via a chemical reaction caused by the interaction between the resist ink and the primer layer, may help mask the pattern on the surface to be patterned. Precisely deposited on top of the chemical layer.

In an illustrative embodiment, a primer layer is formed over an unpatterned device layer on a substrate, and a liquid resist ink is delivered to the primer layer in a pattern, which is then processed (e.g., by drying or Baking the ink to form a solid patterned layer that resists subsequent etching) converts the liquid ink into an etch mask to form an etch mask on top of the primer layer. In an illustrative embodiment, the primer layer includes a first reactive component, the liquid resist ink includes a second reactive component, and when the resist ink contacts the primer layer, the first and The second reactive component reacts to effectively stop the movement of the ink or "freeze" the ink in place so that further shifting or spreading of the ink on the primer surface is greatly reduced or completely stopped. In an illustrative embodiment, the primer layer includes a third reactive component, the liquid resist ink includes a fourth reactive component, and the reaction of the third and fourth reactive components produces an etch mask material , which is relatively insoluble in the resist ink and relatively insoluble in the etching solution used to subsequently etch the unpatterned device layer (where relatively insoluble is defined herein with respect to the fourth reactive component). The etch mask material so formed is referred to herein as a two-component material or two-component reaction product. In various embodiments, the reactive component that provides most of the mass to form the two-component material that makes up the etch mask is called the etch-resist component, or equivalently, the etching component. -resisting component), while the other reactive component is called a fixating component or, equivalently, a fixating reactive component or a fixating composition. In illustrative embodiments, the resist component includes multiple materials. In illustrative embodiments, the immobilization component includes multiple materials. In an illustrative embodiment, the resist ink is a water-based ink, and the two-component material is relatively insoluble in water. In an illustrative embodiment, the etching solution is an acidic etching solution, such as, but not limited to, a mixture of copper chloride and hydrogen peroxide. In illustrative embodiments, one or more of the first component, the second component, the third component, or the fourth component includes multiple materials. In illustrative embodiments, the first and third components are the same. In illustrative embodiments, the second and fourth components are the same. In an illustrative embodiment, the reaction that produces the two-component material is the same reaction that stops a droplet of resist ink from moving on the primer layer. In an illustrative embodiment, the primer layer includes an undercut prevention material. In an illustrative embodiment, the reactive component of the primer (eg, the first or third reactive component described above) includes an undercut prevention material. In an illustrative embodiment, the reactive component of the resist ink (eg, the second or fourth reactive component described above) includes an undercut prevention material. In an illustrative embodiment, the resist ink includes an undercut prevention material.

In illustrative embodiments, at least one of the primer or resist ink can include multivalent and/or polycationic groups and/or multivalent inorganic cations. In illustrative embodiments, at least one of the primer or resist ink may include polyanionic groups. In illustrative embodiments, at least one of the primer or resist ink can include a reactive anionic component and be water-soluble. In illustrative embodiments, such reactive anionic components may include at least one anionic polymer (in base form) with a pH above 7.0. In illustrative embodiments, such anionic polymers may be selected from the group consisting of acrylic resins and styrene-acrylic resins in their dissolved salt form (such as, but not limited to, sodium salt form), sulfonic acid resins in their dissolved salt form ( For example, but not limited to, sodium salt form). In illustrative embodiments, such anionic polymers may be in ammonium form or amine neutralized form. In illustrative embodiments, such anionic polymers may be in the form of polymer emulsions or dispersions. In various embodiments, the reaction producing the two-component material causes a substantial increase in the viscosity of the resist ink on the primer layer, and essentially such viscosity increase causes an immobilization phenomenon. In various embodiments, the resist ink provides most of the material mass forming the two-component material. In various embodiments, the primer provides most of the material mass forming the two-component material, and in such cases, the primer layer may contain the resist component and the resist ink may contain the immobilizing component . In various embodiments, a primer layer is formed by providing a coating of liquid primer ink over an unpatterned device layer and then subsequently processing the layer, such as by drying or baking the layer, to form the primer layer. . In various embodiments, such primer inks are water-based. In various embodiments, the primer layer has good adhesion to the unpatterned device layer. In various embodiments, the primer is applied over the unpatterned device layer by inkjet printing, spray coating, metering rod coating, roller coating, dip coating, or any other suitable printing or coating method. layer. In various embodiments, the primer layer may be a uniform (eg, blanket) coating or may be a patterned coating.

In an illustrative embodiment, a primer layer is formed at least in part by applying a surface activation solution over an unpatterned device layer. In an illustrative embodiment, the surface activation solution includes one or more of copper salts, iron salts, chromic-sulfuric acid, persulfate, sodium chlorite, and hydrogen peroxide. In an illustrative embodiment, the unpatterned device layer is a metal layer and the surface activation solution is applied to the surface of the metal layer. In illustrative embodiments, the surface activation solution may be applied for a predetermined time and then washed off, such as, but not limited to, 10 seconds, 20 seconds, 30 seconds, 60 seconds, or longer. In an illustrative embodiment, the surface activating solution may be applied by immersing the surface in a bath containing the surface activating solution. In illustrative embodiments, the surface activation solution may be applied by spraying the surface with the surface activation solution, or any other suitable method. In an illustrative embodiment, the surface activation solution is washed from the surface using a washing liquid such as, but not limited to, alcoholic solutions, ethanol, propanol, isopropyl alcohol, and acetone. In an illustrative embodiment where the surface is a copper layer (eg, a PCB), a surface-activated aqueous solution of CuCl ₂ (or any divalent copper salt) with a weight percent concentration of 0.5 to 1.0 is utilized, and the primer layer is formed by The copper surface is at least partially formed by immersing it in a bath containing a surface activation solution for 30 seconds. In an illustrative embodiment where the surface is a copper layer (eg, a PCB), a surface-activated aqueous solution of Na ₂ S ₂ O ₈ (or any persulfate) in a weight percent concentration of 0.5 to 1.0 is utilized, and the primer The layer is at least partially formed by immersing the copper surface in a bath containing a surface activation solution for 30 seconds. In an illustrative embodiment in which the surface is a copper layer (eg, a PCB), a surface-activated aqueous solution of H ₂ O ₂ with a weight percent concentration of 10 is utilized, and the primer layer is formed by immersing the copper surface in the surface-activated solution. of the bath for 30 seconds to at least partially form. In an illustrative embodiment in which the surface is a copper layer (such as a PCB), a surface-activated aqueous solution of _FeCl3 with a concentration of 20 weight percent is utilized, and the primer layer is obtained by immersing the copper surface in a bath containing the surface-activating solution. 10 seconds to at least partially form. In an illustrative embodiment in which the surface is a copper layer (eg, a PCB surface), a surface-activated aqueous solution of HCrO ₄ /H ₂ SO ₄ with a weight percent concentration of 5 is used, and the primer layer is formed by immersing the copper surface in a solution containing The surface activation solution is left in the bath for 30 seconds to at least partially form. In an illustrative embodiment in which the surface is a copper layer (eg, a PCB), a surface-activated aqueous solution of _NaClO having a concentration of 5 weight percent is utilized, and the primer layer is formed by immersing the copper surface in a bath containing the surface-activating solution. 60 seconds to at least partially form.

In illustrative embodiments using an inkjet printer to print resist ink onto a primer layer, the substrate may be at approximately "room" temperature, such as in the range of 20°C to 30°C, or may be at elevated temperatures, for example up to 100°C. In illustrative embodiments, the two-component etch mask may have a thickness of at least 0.01 μm. In illustrative embodiments, the two-component etch mask may have a thickness of less than 12 μm.

In an illustrative embodiment of the present invention, a primer layer is deposited onto a substrate, and an etch mask ink is subsequently deposited onto the primer layer using inkjet printing and then baked to form the etch mask layer. Shortly after contacting the primer layer, droplets of the etch mask ink interact with the primer layer, effectively stopping or "freezing" the droplets, thereby greatly reducing or eliminating further spreading and/or migration. bit, which is the result of a chemical reaction between a first reactive component in the primer layer and a second reactive component in the etch mask ink. Additionally, one or more components of the etch mask ink react with one or more components of the primer layer to form a two-component etch mask material that is relatively insoluble in the etch mask ink and relatively insoluble in the etch mask ink. The mask will be used in the etching solution (which is relatively insoluble here defined as relative to the etch mask ink components that react to form the two-component etch mask). For example, the etch mask ink can be aqueous and the etch mask material resulting from such a reaction is insoluble in water, and the etching solution can be an acidic etch solution and the etch mask material resulting from such a reaction is insoluble. in the acidic etching solution.

In an illustrative embodiment, coating an unpatterned device layer (such as a copper layer) with an undercut-preventing material (such as a corrosion-resistant material) may be applicable to any device layer material that uses an etch mask to protect the device layer material from wet etching. method. Other metal layers other than copper may be used in illustrative embodiments, including but not limited to, for example, aluminum, stainless steel, gold, and metallic alloys. Illustrative embodiments of the present invention include introducing the undercut reduction material as a primer layer prior to applying the photoresist layer to the unpatterned device layer, such as via lamination, slot coating, or spin coating, which This is followed by patterning via exposure to light of selected wavelengths (eg, UV light), through a photomask, or via direct laser imaging.

The action of the undercut reduction material during the chemical etching process may mitigate (eg, reduce, eliminate) the occurrence of undercutting of device layer features caused by the patterning process. Accordingly, following a chemical etching process, due to the reduction or elimination of undercuts, device layer features may be formed that have more vertical and less sloping sidewalls than a device layer formed without undercut reduction material. When applied to patterned device layers containing conductive materials capable of carrying electrical current or electrical signals, various embodiments of the present invention can enhance the overall performance of the electrical circuit so formed, improve the overall conductivity of individual conductive features, enhance frequency responsive and enables the fabrication of patterns with higher density and thinner features and thinner spacing between features. Similar benefits may be obtained in components that use patterned device layers of non-metallic materials, such as optical or insulating patterned features.

It is believed that during a conventional wet etch procedure, as the liquid etchant travels downward (eg, toward the substrate) through the thickness of the device layer material being etched in those areas not covered by the etch mask, the liquid etch The agent also advances laterally into the side surfaces (eg, sidewalls) of those portions of the device layer material covered by the etch mask. As etch depth increases, more of the sidewall is exposed to lateral etch, such that the portion of the sidewall closest to the etch mask is exposed to the liquid etchant for a longer period of time than the portion of the sidewall closest to the substrate, and therefore is subject to increased lateral etch, so The sidewalls that characterize the resulting patterned device layer are undercut. In other words, the time it takes for the etchant to react with the device layer material to remove portions of the device layer material increases with distance from the substrate. While not wishing to be bound by any particular theory, it is believed that in conventional wet etching procedures, whether performed by dipping or spraying or spraying the etchant, there is a significant gap between the etchant and portions of the device layer material remote from the substrate. The additional reaction time results in laterally inward erosion (removal) of the device layer material in areas directly beneath and adjacent to the etch mask features, although the purpose of the etch mask is to prevent removal of the device layer material in those areas . Further explanation and description of this phenomenon are provided below in conjunction with Figures 4B-5C.

As discussed in various illustrative embodiments in accordance with the present invention, the reaction between the etchant and the portions of the device layer material corresponding to the side surfaces (or equivalently, the sidewalls) of the patterned device layer features during the wet etching process The period is mitigated (e.g., reduced, prevented, inhibited), thereby mitigating the formation of undercut shapes on the side surfaces.

1A-5C all illustrate various stages of processing a device to form a patterned device layer on a substrate (or equivalently, patterned device layer features on a substrate) according to various conventional methods. In an illustrative embodiment, the device is a PCB in process and the device layer material is a conductive material. However, those skilled in the art will understand that references to PCB are non-limiting and illustrative only, and that various applications are encompassed within the scope of the present invention, such as the various electronic and optical components mentioned above. Referring now to FIGS. 1A-1D , various views of a device 100 undergoing processing according to one known method to form patterned device layer features are shown. 1A is a plan view and a side view of a device 100 including a substrate 102 having an unpatterned device layer 104 disposed thereon.

The substrate 102 itself may include multiple layers, such as, but not limited to, one or more unpatterned or patterned device layers. For example, although the unpatterned device layer 104 is shown on one side of the substrate 102 (eg, the "top" in the illustrated orientation), the present invention also contemplates "double-sided" processing of the device 100, e.g., where the substrate 102 includes a second unpatterned device layer positioned on the opposite side (eg, "bottom") that encompasses the substrate 102 . In an illustrative embodiment, such a "bottom" side unpatterned device layer is subjected to a similar patterning process as the "top" side unpatterned device layer 104 , and such "bottom" side is fully or partially patterned occurs before, after, or during patterning of the "top" side of the unpatterned device layer 104. In illustrative embodiments, substrate 102 may include one or more patterned device layers processed in accordance with one or more illustrative embodiments, such as, but not limited to, in a manner similar to that used to process unpatterned device layer 104 The way.

In one illustrative embodiment, device 100 is a PCB in-process, unpatterned device layer 104 includes an electrically conductive material, thereby making it an unpatterned conductive device layer, and substrate 102 includes one or more layers of electrically insulating material that is Configured to provide a "top" electrically insulating surface and a "bottom" electrically insulating surface, the unpatterned conductive device layer 104 is positioned adjacent the "top" electrically insulating surface. A second unpatterned electrically conductive device layer is incorporated into substrate 102 and positioned adjacent a "bottom" electrically insulating surface (where such "bottom" electrically insulating surface is on substrate 102 and not shown in FIG. 1 ), and the "bottom" surface of substrate 102 , ie, the surface on the opposite side of substrate 102 relative to the surface adjacent to unpatterned device layer 104 , is the second unpatterned device layer 104 . chemically conductive device layer.

In one illustrative embodiment, device 100 is a PCB in process, and substrate 102 has an electrically insulating surface over a region that includes at least a portion of the interface between substrate 102 and unpatterned device layer 104 . In one illustrative embodiment, substrate 102 may include a layer of electrically insulating material, such as, but not limited to, a composite material including woven glass bonded by epoxy or other materials. Such electrically insulating materials may have a thickness in the range of about 0.001 inches to about 0.05 inches, for example. In one illustrative embodiment, substrate 102 may include a plurality of alternating layers of electrically insulating and conductive materials, further including at least two electrically insulating layers, each layer including woven glass bonded by epoxy or other materials and having A thickness between 0.001 inches and 0.05 inches, such as a "core" layer and a layer containing a prepreg adhesive sheet (which may be referred to as a "prepreg"), and between electrically insulating layers At least one patterned conductive layer, wherein the "top" surface of the substrate 102 that interfaces with the unpatterned device layer 104 is the surface of one of at least two electrically insulating layers. In an illustrative embodiment, the prepreg includes an FR4 grade epoxy laminate. In an illustrative embodiment, the core layer includes an FR4 grade epoxy laminate.

The unpatterned device layer 104 may include a layer of conductive material such as, for example, a metal or metal alloy including, but not limited to, copper, aluminum, silver, gold, or other conductive materials, which are familiar to those skilled in the art. In the illustrative embodiment, unpatterned device layer 104 is copper foil laminated to substrate 102 , wherein the interface surface between substrate 102 and unpatterned device layer 104 is electrically insulating; however, other conductive materials are considered to be within the scope of the invention.

Referring now to FIG. 1B , in the next stage of processing, an etch mask 106 is formed over the exposed surface 110 of the unpatterned device layer 104 . The etch mask 106 may be formed in a desired pattern 108, such as lines corresponding to where patterned device layer lines are desired on the device 100 after processing, as shown in Figure IB. In other words, etch mask 106 may include resist material deposited over unpatterned device layer 104 at locations corresponding to desired features of the patterned device layer in device 100 . Etch mask 106 may include materials such as, for example, polymers, oxides, nitrides, or other materials. In one illustrative embodiment, the etch mask material is a polymer formed using a negative photoresist material, such as, but not limited to, the SU-8 series photoresists supplied by MicroChem Corp., 200 Flanders Road, Westborough, MA 01581 USA one. In one illustrative embodiment, the etch mask material is a polymer formed using a positive photoresist material such as, but not limited to, ma-P 1200 supplied by micro resist technology GmbH., Köpenicker Str. 325, 12555 Berlin, DE. One of a series of photoresists. Etch mask 106 may be patterned over the surface of unpatterned device layer 104 by methods such as screen printing, inkjet printing, photolithography, gravure printing, stamping, photoengraving, or other methods. After applying etch mask 106 to surface 110 of unpatterned device layer 104 , device 100 is exposed to an etchant, such as a chemical etchant, which removes the unpatterned device from those areas not protected by etch mask 106 The material in layer 104 results in the formation of patterned device layer 114, as shown in Figure 1C. Such chemical etchants may include compounds that have a corrosive effect on the material of unpatterned device layer 104 . In an illustrative embodiment, unpatterned device layer 104 is a conductive layer, and such chemical etchants may include, but are not limited to, ammonium persulfate, ferric chloride, or those having a corrosive effect on the material of unpatterned device layer 104 Other compounds. In one specific example, the unpatterned conductive device layer 104 includes copper, and the etchant used is copper chloride (CuCl ₂ ). Those skilled in the art are familiar with various chemical etchants suitable for removing material from unpatterned device layer 104 .

Continuing with reference to FIG. 1C , when unpatterned device layer 104 is exposed to an etchant, the etchant dissolves (eg, erodes) the material of unpatterned device layer 104 starting at exposed top surface 110 . As the material of the unpatterned device layer 104 is removed, the etchant may also remove portions of the material of the unpatterned device layer 104 beneath the etch mask 106 , leaving non-straight and non-vertical sidewalls 112 . For example, as shown in FIG. 1C , in a device 100 fabricated according to the method shown in FIGS. 1A-1D , the sidewalls 112 of the features of the patterned device layer 114 resulting from the pattern 108 of the etch mask 106 may exhibit a tapered shape. , for example, from a first feature width W1 at the interface between the patterned device layer 114 and the etch mask 106 to a second feature width W1 at the interface between the substrate 102 and the patterned device layer 114 that is wider than the first feature width. Taper with characteristic width W2. FIG. ID shows device 100 after etch mask 106 has been removed, exposing patterned device layer 114 . The tapering of sidewalls 112 featured by patterned device layer 114 in FIG. 1D is an illustration of an "undercut" sidewall, and is discussed in further detail below in conjunction with FIGS. 4A-4C . Other shapes and arrangements of undercut sidewalls are also possible and may include sidewalls that are not substantially straight and sidewalls that do not extend substantially perpendicularly from the substrate surface on which they are formed.

Referring now to FIGS. 2A-2C , a method of forming an etch mask 206 having a pattern 208 of conductive lines is shown. Device 200 having substrate 202 and unpatterned device layer 204 covers the entire area of unpatterned device layer 204 with unpatterned resist layer 216 (ie, blanket coating). The unpatterned resist layer 216 is then exposed to light (eg, UV light) in a pattern such that the exposed areas are relatively difficult to remove during a subsequent development process (so-called negative processing), or so that the exposed areas are not susceptible to subsequent development. Relatively easy to remove from the program (so-called positive processing). Such patterning using exposure may be accomplished, for example, by shining light through a mask as in so-called photolithography processes, or by delivering a stream of focused light to the resist layer 216 in a pattern as a function of time (e.g., with This is achieved in the form of laser beam pulses or scans, which is the so-called direct writing process. The development process corresponding to the patterned exposure removes material in the unpatterned resist layer 216, resulting in a patterned etching mask 206 having the pattern 208, as shown in FIG. 2C. The developing process may include immersing the device 200 in a liquid developer that dissolves or corrodes materials that are relatively easier to remove in the unpatterned etch mask layer 216, such as, but not limited to, in a negative tone process. In this case, the developer liquid may be dissolved in the material in the unpatterned resist layer 216 that has not been exposed to UV light; and in the case of a positive process, the developer liquid may be dissolved in the unpatterned resist layer 216 Materials that have been exposed to UV light. Portions of unpatterned device layer 204 that are not protected by etch mask 206 are then removed as discussed above in connection with FIG. 1D , resulting in device 200 having a patterned device layer having the characteristics and behavior of pattern 208 Out the undercut.

Alternatively, the etch mask can be deposited directly over the unpatterned device layer in the desired pattern without requiring the intermediate step of patterning the unpatterned resist layer as in the specific examples of Figures 2A-2C. For example, referring now to Figures 3A and 3B, an etch mask 306 can be formed directly over the unpatterned device layer 304 of the device 300 in a desired pattern 308 of lines that correspond to the desired pattern on the resulting device. The location of features on the device layer. Etch mask 306 may be deposited on unpatterned device layer 304 in a desired pattern 308 by, for example, inkjet printing, lamination, screen printing, gravure printing, stamping, or other methods. In one illustrative embodiment, etch mask 306 is formed over unpatterned device layer 304 using inkjet printing, where an inkjet print head having a plurality of nozzles ejects droplets of liquid resist ink onto device 300 A coating of liquid resist ink corresponding to pattern 308 is formed, and the coating of liquid resist ink is subsequently processed to convert the liquid coating into an etch mask 306 . In another illustrative embodiment, processing of liquid resist ink includes drying and/or baking the device to form solid etch mask 306 from the liquid coating. In one illustrative embodiment, etch mask 306 is formed over unpatterned device layer 304 using an inkjet printer including one or more printheads including a plurality of nozzles, a substrate supporting the substrate a support, a stage for relatively moving the plurality of nozzles and the substrate, a motion control system for controlling the relative positions of the substrate and the nozzles, and controlling the emission of the nozzles to deliver droplets to the substrate in a desired pattern nozzle control system. It is contemplated by the present invention that in any embodiment in which inkjet printing is utilized to deposit a liquid coating, an inkjet printing system such as that described herein may be used.

4A-4C illustrate a conventional method for removing material from the unpatterned device layer 404 from the device 400 and depict conditions believed to occur during a wet etch procedure that result in undercutting. In Figure 4A, unpatterned device layer 404 is covered by etch mask 406 corresponding to pattern 408. Device 400 is then exposed to chemical etchant 418. In the illustrative embodiment of Figure 4B, the exposure is performed by immersion in the etchant 418. Etchant 418 removes material from unpatterned device layer 404 (from FIG. 4A ) to create partially patterned device layer 405 . For example, in the specific example of FIG. 4B , etchant 418 contains a liquid, such as a restricted solution, contained within container 420 , and device 400 having etch mask 406 ( FIG. 4B ) is immersed in etchant 418 , as shown in Figure 4B. Once the exposed portions of top surface 410 (FIG. 4A) of unpatterned conductive layer 404 are etched away and sidewalls 412 begin to form, sidewalls 412 are exposed to the etchant 418 and the etchant 418 removes material from the sidewalls 412, resulting in The characteristic tapered, undercut shape of patterned device layer 414 shown in Figure 4C. In other words, once the top surface 410 of the unpatterned device layer 404 is etched away, the etchant 418, which can act universally in all directions, will laterally attack the device layer-containing material beneath the etch mask 406 (regardless of the The device layer is in its unpatterned state, 404; in its partially patterned state, 405; or in its patterned state, 414). The amount of device layer material removed by etchant 418 may depend on the amount of time the device layer material is exposed to etchant 418 . Therefore, as the etchant 418 travels through the thickness of the portion of the patterned device layer 405 (ie, in a direction perpendicular to the plane of the substrate 402 ), the portions of the sidewalls 412 that are closer to the etch mask 406 are closer to the substrate 402 than the sidewalls 412 The portions are exposed to the etchant 418 for a longer period of time, and the etching process thereby gives the sidewalls 412 the tapered (ie, undercut) shape shown in Figure 4C. In other words, the time it takes for the etchant to react with materials in the device layer to remove such material from the device layer increases with distance from the substrate. While not wishing to be bound by any particular theory, it is believed that therefore the additional reaction time between the etchant and the material in those portions of the device layer remote from the substrate results in the formation of lithium ions from the device in areas of the device layer directly beneath or near the etch mask. Lateral inward erosion (removal) of the layer's material, although the purpose of the etch mask is to prevent removal of device layer material in those areas.

Referring now to Figures 5A-5C, a specific example of another conventional method is shown. The method of Figures 5A-5C is similar to that described in connection with Figures 4A-4C and includes forming an etch mask 506 over the unpatterned device layer 504 of the device 500, as shown in Figure 5A. Rather than immersing the device 500 in the etchant 518 as described above in connection with Figure 4B, the etchant 518 is introduced with a jet 522 directed to the device 500, which can be in a container 520, as shown in Figure 5B. Excess etchant 518 may flow into drain 524 of container 520 or otherwise be collected, such as for recycling or other processing. Because the etchant 518 acts omnidirectionally, a taper or undercut is formed on the resulting sidewalls 512 of the features of the patterned device layer 514, as shown in Figure 5C.

As discussed above, undercut sidewalls having features formed on a patterned device layer on the device introduce various limitations on the size and shape of the features that can be formed. For example, as discussed above, the tendency to form undercuts may limit the minimum feature width or minimum feature-to-feature spacing that can be produced, thereby limiting feature density on the device. In a variety of applications, maximizing feature density on a device can improve performance. In various embodiments, the device layers include conductive materials, the device is a PCB, and the tendency for undercutting may limit minimum feature width, minimum feature-to-feature spacing, and maximum feature density.

6A-17 illustrate various specific examples of methods for mitigating (eg, reducing or eliminating) undercutting that occurs during conventional processes. For example, referring now to FIG. 6A , device 600 has unpatterned device layer 604 over substrate 602 . Unpatterned device layer 604 may be formed by chemical vapor deposition, physical vapor deposition, lamination, slot coating, spin coating, inkjet printing, screen printing, nozzle printing, gravure printing, bar coating, or any Other suitable methods can be applied to the substrate, such as those familiar to those skilled in the art. The unpatterned device layer 604 is coated with an anti-corrosion layer 629 before an etch mask 628 is formed over the anti-corrosion layer 629 . The anti-corrosion layer 629 can be formed by chemical vapor deposition, physical vapor deposition, lamination, slot coating, spin coating, inkjet printing, screen printing, nozzle printing, gravure printing, rod coating, or any other suitable method. methods such as those familiar to those skilled in the art. In some embodiments, the anti-corrosion layer 629 includes a "primer" layer, and the etch mask 628 is formed by depositing a liquid resist ink over the primer layer, which liquid resist ink is dried by, for example, but not limited to, Or post-processing of the bake transforms into an etch mask 628 . In various embodiments, as previously described, such liquid resist ink can be delivered to device 600 in droplet form via inkjet printing, and can be combined with anti-corrosion layer 629 (which in this case serves as a primer layer interaction), such droplets effectively stop moving or "freeze" in place quickly (for example, on the order of microseconds) when in contact with the primer surface, thereby causing further displacement of the ink droplets on the primer surface or Diffusion is greatly reduced or completely stopped, as further discussed in International Publication Nos. WO2016/193978 A2 and WO2016/025949 A1, incorporated by reference above. Such liquid resist inks may further produce a two-component material that at least partially forms a resist mask via interaction with such a primer layer.

In various embodiments, referring to FIG. 6A , device 600 is a PCB, unpatterned device layer 604 includes a conductive material such as copper, aluminum, gold, and/or other metals, and is adjacent to unpatterned conductive device layer 604 The surface of substrate 602 is electrically insulating.

In the illustrative embodiment, corrosion resistant layer 629 may include a material selected based on its ability to block the corrosive effects of chemical etchants used to remove materials from unpatterned device layer 604 of device 600 . As non-limiting examples, the anti-corrosion layer 629 may include, but is not limited to, polymers; organic compounds, such as include one or more imine groups, one or more amine groups, one or more -azole groups, One or more hydrazine groups, one or more organic compounds of amino acids; Schiff bases; or other materials. In other illustrative embodiments, corrosion resistant layer 629 may include an inorganic material such as chromate, molybdate, tetraborate, or another inorganic compound. In some illustrative embodiments, corrosion-resistant layer 629 may include reactive components, such as one or more reactive cationic groups including polycations and/or multivalent cations. The cationic reactive component is capable of attaching to metallic surfaces, such as copper surfaces.

In some embodiments, the corrosion-resistant layer 629 may be formed by applying a liquid corrosion-resistant ink over an unpatterned device layer using any known application method, such as, but not limited to, spray coating, spin coating, nozzle printing , bar coating, screen printing, painting, inkjet printing, etc., the device 600 is then processed to convert the liquid coating into an anti-corrosion layer 629. In some embodiments, the anti-corrosion layer 629 may be referred to as a primer layer, and the liquid anti-corrosion ink may be referred to as a primer ink. The liquid corrosion resistant ink may comprise a solution which may comprise a polyimine such as, for example, a polyethyleneimine having a low molecular weight or a high molecular weight, such as a linear polyethyleneimine or a branched polyethyleneimine. As a non-limiting example, the molecular weight may range from about 800 to about 2,000,000.

In some embodiments, in order for the liquid corrosion-resistant ink to be ejectable via an inkjet printhead, the liquid ink may be an aqueous solution, which may include additional reagents such as propylene glycol, n-propanol, and wetting additives such as those supplied by Evonik Industries TEGO 500).

In some embodiments, the thickness of corrosion-resistant material layer 629 may range from about 0.03 μm to about 1.1 μm. In some embodiments, the method may include drying the applied ink using any drying method to form a solid coating. In some embodiments, the method may include baking the applied ink using any drying method to form a solid coating.

As a further non-limiting example, if present, the cationically reactive components of corrosion-resistant material layer 629 may include polyamides, such as polyethylenimines, polyquaternary amines, long chain quaternary amines, polyamides at various pH levels. tertiary amines; and polyvalent inorganic cations such as magnesium, zinc, calcium, copper, iron and ferrous cations. The polymerizable components can be introduced into the formulation as soluble components or in emulsion form.

The corrosion-resistant material layer 629 may be applied to the unpatterned device layer 604 using any suitable printing or coating method, including, but not limited to, inkjet printing, spray coating, metering rod coating, roller coating, dipping Coating, spin coating, screen printing, laminating, stamping and others. The anti-corrosion layer 629 may be applied uniformly over the unpatterned device layer 604 or in a desired pattern, such as the desired pattern of the patterned device layer 630 as defined in pattern 608 (per FIG. 6 ).

In the illustrative embodiment of FIGS. 6A-6D , the corrosion-resistant layer 629 may include a "primer" layer, and the etch mask 628 may be formed by depositing a liquid resist ink over the primer layer, which liquid resists corrosion. The agent ink is converted into an etch mask 628 via subsequent processing such as, but not limited to, drying or baking. In various embodiments, such drying may include baking, such as, but not limited to, at 70° C. or higher. In various embodiments, as previously described, such liquid resist ink can be delivered to device 600 in the form of droplets via inkjet printing, and can interact with the primer layer such that such droplets interact with the primer layer. The paint surface stops moving or "freezes" in place quickly (e.g., on the order of microseconds) upon contact, thereby greatly reducing or completely stopping the further displacement or spreading of the ink droplets on the primer surface, as further discussed in International Publication No. WO2016 /193978 A2 and WO2016/025949 A1, are hereby incorporated by reference. Such liquid resist ink may further produce a two-component material that at least partially forms an etch mask via interaction with such a primer layer.

The etch mask 628, or the liquid resist ink used to make such an etch mask 628 (according to various embodiments as described above) may include polymeric components that are water-soluble and may include anionic groups. group. The anionic polymer may be selected from acrylic resins and styrene-acrylic resins in their dissolved salt form. The anionic polymer may be selected from sulfonic acid resins in their dissolved salt form, such as sodium, ammonium neutralized or amine neutralized forms. In specific examples utilizing liquid resist inks, the liquid inks may include additional agents used to improve printing or other deposition qualities of the material.

The etch mask 628, or, the liquid resist ink used to make such an etch mask 628 (according to certain embodiments as described above) may include a reactive component, which may be water-soluble and may include Reactive anionic group. Non-limiting examples of anionic reactive components may include at least one anionic polymer (in base form) with a pH above 7.0. The anionic polymer may be selected from acrylic resins and styrene-acrylic resins in their dissolved salt form. The anionic polymer may be selected from sulfonic acid resins in the form of their dissolved salts, such as, but not limited to, sodium salt form, ammonium or amine neutralized form, and in the form of polymer emulsions or dispersions. The polymerizable components can be introduced into the formulation as soluble components or in emulsion form.

Referring to FIG. 6B , the anti-corrosion layer 629 and the etching mask 628 can be directly printed on the device 600 . In one illustrative embodiment, the anti-corrosion layer 629 may be formed via printing in a desired pattern, such as pattern 608, over the unpatterned device layer 604 to facilitate fabrication of a corresponding patterned device layer 630 (Fig. shown in 6). The anti-corrosion layer 629 may be deposited to a thickness in the range of about 5 nm to about 100 nm, about 100 nm or less, or about 1 μm or less. Other thicknesses of corrosion resistant material layer 629 are considered to be within the scope of the invention and may depend on the specific application. An etch mask 628 is then formed via printing in a desired pattern (such as pattern 608) over the layer of corrosion-resistant material 629 to facilitate fabrication of a corresponding patterned device layer 630 (as shown in Figure 6). For example, etch mask 628 may be deposited to have a thickness in the range of about 1 μm to about 5 μm, or about 5 μm or less, or about 15 μm or less.

The device 600 is then introduced into an etchant, such as the liquid chemical etchants 418 or 518 discussed in connection with Figures 4B and 5B. As shown in Figures 6C and 6D, the presence of a layer of corrosion-resistant material 629 may help reduce the amount of undercutting of features of patterned device layer 630. For example, the patterned device layer 630 may be characterized by a first width W1 proximate the corrosion resistant layer 629 and a second width W2 proximate the substrate 602 . In some illustrative embodiments, the difference between widths W1 and W2 results in features of patterned device layer 630 exhibiting tapered sidewalls 632 (ie, features of patterned device layer 630 may exhibit some degree of undercut). The undercut exhibited by features of patterned device layer 630 may be less than the undercut exhibited by features of patterned device layers 114, 414 (Figures ID and 4D) as discussed above. Various measurements can be used to quantify the extent of undercut, as discussed in more detail below in connection with Figures 10 and 11.

In the illustrative embodiment of FIGS. 7A-7C , corrosion-resistant layer 729 is deposited across the surface of unpatterned device layer 704 disposed on substrate 702 . Such blanket coating may be accomplished by methods such as, but not limited to, chemical vapor deposition, physical vapor deposition, lamination, inkjet printing, spray coating, metering rod coating, roller coating, dip coating, spin coating, stencil coating printing, nozzle printing, or other methods. Etch mask 728 may be formed over corrosion-resistant layer 729 in a desired pattern, such as pattern 708, as discussed above with respect to various embodiments. The method proceeds similarly to the specific examples of Figures 6A-6C described above. For example, device 700 with corrosion-resistant layer 729 and etch mask 728 is exposed to an etchant, such as etchants 418 or 518 discussed in connection with Figures 4B and 5B. As shown in Figure 7B, device 700 is placed in container 720, and etchant 718 is sprayed over the surface of device 700 with etch mask 728 disposed thereon. Etchant 718 may remove corrosion-resistant layer 729 from the surface of unpatterned device layer 704 and expose the material of unpatterned device layer 704 removed by etchant 718 as shown in FIG. 7B to form patterning with sidewalls 732 Device 730, sidewalls 732 exhibit a reduced degree of undercut compared to sidewalls 112 associated with patterned device layers 114, 414 fabricated according to conventional methods. Partially patterned device layer 705 reflects the device layer after corrosion-resistant layer 729 has been removed from those areas exposed through the etch mask and some material of the device layer itself has been etched away, and before the etching has developed sufficiently to form patterned device 730 intermediate state.

Referring now to Figures 8A-8D, a portion of the method of the specific example of Figures 7A-7C is described in greater detail. In FIG. 8A , a jet 822 of etchant, such as etchant 718 in FIG. 7B , strikes an anti-corrosion layer 829 and etch mask 828 surface deposited on an unpatterned device layer 804 on a substrate 802 . The anti-corrosion layer 829 may adhere preferentially to the material surface of the device layer and may also be at least partially soluble in the etchant 718 , while the resist material 828 may be substantially insoluble in the etchant 718 . The jet 822 of the etchant 718 may contain sufficient kinetic energy to remove the anti-corrosion layer 829 from the unpatterned device layer 804 in those areas exposed through the etch mask, as shown in FIG. 8B , and the etchant 718 may then begin removal. The material of unpatterned device layer 804 that is not covered by resist material 828 forms partially patterned device layer 805 as shown in Figure 8C. 8D shows device 800 after portions of patterned device layer 805 have been sufficiently etched to form patterned device layer 830. As shown in Figure 8D, patterned device 830 has sidewalls 832 that exhibit less undercutting than sidewalls fabricated according to conventional methods described in conjunction with Figures 1A-5C. Although patterned device 830 is shown in Figure 8D with a slight undercut, the present invention contemplates patterned device layers (e.g., conductive ) characteristics.

Referring now to FIGS. 9A-9C , another specific example of a method for forming patterned device layer 930 on device 900 is shown. The unpatterned device layer 904 disposed over the substrate 902 is shielded by an anti-corrosion layer 929 and an etch mask 928 . The device 900 and the etchant 918 are introduced into the container 920 such that the device is immersed in the etchant 918 in Figure 9B. As shown in FIG. 9C , the resulting patterned device layer 930 of device 900 has sidewalls 932 that exhibit less undercutting than the undercut exhibited by the conductive features 114 associated with conventional methods ( FIG. 1D ). Small degree of undercut.

Referring now to Figure 10, an enlarged view of the device 100 discussed in connection with the conventional method of Figures 1A-5C is shown. In FIG. 10 , patterned device layer 114 is characterized by tapered sidewalls extending between the interface of etch mask 106 and patterned device layer 114 and the interface between patterned device layer 114 and substrate 102 . Patterned device layer feature 114 exhibits a first width W1 at the interface of patterned device layer 114 and etch mask 106 and a second width W2 at the interface of patterned device layer 114 and electrically insulating substrate 102 . Figure 10 is drawn for illustrative purposes, and variations in profile may occur, but generally speaking, the patterned device layer 114 has a wider width at the interface with the substrate than at the interface with the resist material. It should be noted that the etch mask 106 has a width W3, which is contemplated by the present invention to be greater than, less than, or equal to the width W2.

Referring now to Figure 11, which is an enlarged view of a device 1100 similar to device 600, 700, 800, or 900 shown in Figures 6A-9C. In this illustrative embodiment, the features of patterned device layer 1130 exhibit a first width W1 at the interface between patterned device layer 1130 and corrosion-resistant layer 1129 , and between patterned device layer 1130 and substrate 1102 The second width W2 is displayed on the interface. It should be noted that etch mask 1128 has a width W3, which is contemplated by this disclosure to be greater than, less than, or equal to width W2.

An exemplary measure of the degree of undercut is the etch factor F, which is the ratio of the difference in width of the widest and narrowest portions of the feature of the patterned device layer to the height of the feature of the patterned device layer. Therefore, the etch factor F is defined as H/X, where H is the height of the line (H) and Divide the difference by 2. Figure 11 illustrates the relationship between H and X. Exemplary values for etch factor F for patterned device layer features of the present invention are discussed below in conjunction with Examples 1-3. As non-limiting examples, device layer features associated with devices fabricated in accordance with various illustrative embodiments of this invention may exhibit an etch greater than 2, greater than 5, greater than 7, or greater, such as greater than 10, greater than 20, etc. Factor F. As another example, as the value of Measurements of H, W1, and W2 can be performed using a variety of microscopy techniques that measure surface profile, cross-section, and film thickness, such as, but not limited to, surface profilometry, scanning electron microscopy, ellipsometry, and confocal microscopy.

While not wishing to be bound by a particular theory, the inventors believe that during the etch procedure, portions of the layer of corrosion-resistant material detached from the layer and adhered and/or adsorbed to the sidewalls of the device layer beneath the etch mask to mitigate Undercut. Figures 12A and 12B depict this phenomenon.

Figure 12A shows a cross-sectional view of apparatus 1200 during intermediate processing steps in a patterning method in accordance with various illustrative embodiments of the present invention. As shown, a portion of patterned device layer 1205 on substrate 1202 is undergoing an etching process. Figure 12B shows an enlarged view of a portion of Figure 12A at the interface between sidewalls 1232 of partially patterned device layer 1205 and corrosion resistant layer 1229. As shown in FIG. 12B , when the device 1200 is exposed to the etchant 1218 , the corrosion-resistant material portion 1246 including the corrosion-resistant layer 1229 is separated from the corrosion-resistant layer 1229 due to the action of the etchant 1218 , such as, but not limited to, by partial dissolution. Anti-corrosion layer, and such anti-corrosion material then travels and adheres to and/or adsorbs to the sidewall 1232. In other words, the presence of etchant 1218 may assist in displacing corrosion-resistant material portion 1246 containing corrosion-resistant layer 1220 from corrosion-resistant material layer 1229 to sidewall 1232 of portion of patterned device layer 1230 during the etching procedure. The presence of corrosion-resistant material portions 1246 on sidewalls 1232 may then inhibit the corrosive effects of etchant 1218 on sidewalls 1232 , thereby reducing (eg, reducing or eliminating) the amount of undercut exhibited in the resulting patterned device layer 1230 . In various illustrative embodiments, it is believed that at least two processes contribute to these phenomena, in which in one process the corrosion-resistant material is dissolved by the etchant, and in another simultaneous process, the corrosion-resistant material is dissolved in the etchant. Corrosion material is adsorbed and/or adhered to sidewall 1232. In various illustrative embodiments, the rates of the first and second processes are such that portions of corrosion-resistant material 1246 are formed and maintained during the etching process to reduce (eg, reduce or eliminate) the amount of undercut produced.

As shown in FIG. 12B , it is believed that in some cases, the portion 1246 of the corrosion-resistant material adsorbed to the sidewall 1232 may exhibit a generally tapered shape, with the adhesion and/or adsorption layer 1246 of the corrosion-resistant material proximate the corrosion-resistant material layer 1229 A greater thickness is exhibited, and a decreasing thickness is exhibited along layer 1246 away from the corrosion resistant material layer 1229 and toward the substrate.

13A, 13B, and 13C illustrate additional examples of processes in which particles 1348 of corrosion-resistant material are believed to detach from the corrosion-resistant layer 1329 and adhere and/or adsorb to the sidewalls 1332 of the partially patterned device layer 1305 of the device 1300. . 13B and 13C show enlarged views of the interface between the corrosion-resistant material layer 1329 and the partially patterned device layer sidewalls 1332. As shown in Figure 13B, particles 1348 of corrosion-resistant material are separated from the layer 1306 of corrosion-resistant material. In FIG. 13C , detached particles 1348 are attached and/or adsorbed to sidewalls 1332 of partially patterned device layer 1305 . Isolated particles 1348 may adhere to and/or adsorb to sidewall 1332 in a generally decreasing thickness pattern in a direction away from corrosion-resistant material layer 1329 . It is believed that in various cases, separated particles 1348 may be adsorbed to and/or attached to sidewall 1332 in a substantially uniform pattern, in a substantially random pattern, or in some other pattern. The presence of particles 1348 on sidewalls 1332 may inhibit the effects of etchant 1318 and mitigate (eg, reduce or eliminate) undercutting that occurs on portions of patterned device layer 1305 during the etching process. As discussed above with respect to Figure 12, in various illustrative embodiments, it is believed that at least two processes contribute to these phenomena, wherein in one process the corrosion-resistant material is dissolved by the etchant and in another simultaneous process , the corrosion-resistant material dissolved in the etchant is adsorbed and/or adhered to the sidewalls 1332, and in various embodiments, the first and second processes are performed at a rate such that portions of the corrosion-resistant material are formed and maintained during the etching process. 1346 to reduce (e.g. reduce or eliminate) the amount of undercut observed.

14 is a flowchart illustrating an illustrative embodiment of a workflow 1400 for forming a device, such as, but not limited to, an electrical or optical component or device in accordance with the present invention. At 1402, an unpatterned device layer is prepared on the substrate. For example, an unpatterned device layer (eg, a conductive film) is laminated or otherwise deposited onto the electrically insulating surface of the substrate. At 1404, an undercut resistant etch mask is formed, such as by depositing a corrosion resistant layer over the unpatterned device layer and depositing an etch mask over the corrosion resistant material. For example, a liquid primer ink containing an anti-corrosion material is blanket-coated onto a substrate and then dried to form an anti-corrosion primer layer, and a liquid etch mask ink is printed on the anti-corrosion primer layer and then dried. to form an etching mask. The primer layer and etch mask together form an undercut resistant etch mask. The undercut-resistant etch mask may include a corrosion-resistant layer as discussed in the illustrative embodiments above (such as, for example, corrosion-resistant layer 629, 729, 829, 929, 1129, 1229, or 1329) and an etch mask (such as, For example, etching mask 628, 728, 828, or 928). As mentioned above, the primer layer and liquid etch mask ink can interact to form a two-component material. As mentioned above, the primer layer and the liquid etch mask ink can interact, effectively causing the ink to freeze or freeze on the surface of the primer. At 1406, a wet etch is performed to remove areas of the unpatterned device layer that are not covered by the etch mask (ie, exposed portions of the unpatterned device layer). The wet etch can be performed in sufficient time to remove the exposed portions of the unpatterned device layer, leaving the patterned device layer corresponding to the features covered by the etch mask. At 1408, the etch mask is stripped, such as by dipping the device or spraying the device with a stream of stripping fluid designed to dissolve and thereby remove the etch mask to expose the resulting patterned device layer on the device. In various further embodiments, the stripping process also removes the corrosion-resistant layer beneath the etch mask.

15 is a flowchart illustrating in greater detail an illustrative embodiment of a workflow 1500 for forming an undercut-resistant etch mask, such as discussed above in conjunction with 1404, on a substrate in accordance with the present invention. At 1502, an anti-corrosion layer is formed on the substrate with the unpatterned device layer, such as, for example, anti-corrosion layer 629, 729, 829, 929, 1129, 1229, or 1329. In the specific example of Figure 15, the corrosion-resistant layer is formed as a blanket coating (ie, the unpatterned layer) over the entire surface of the unpatterned device layer. At 1504, an etch mask, such as etch mask 628, 728, 828, or 928, is formed over the surface of the corrosion-resistant layer in the blanket coating. At 1506, the resist material is directly exposed or exposed, such as by exposure to a pattern of UV light, as discussed generally in connection with Figures 2A-2C. At 1508, the resist material is developed to form a patterned etch mask, such as, for example, by removing the resist material that was not exposed to UV light (in the case of a negative process) or exposed to UV light (in the case of a negative process). In the case of the positive process) the resist material.

16 is a flowchart illustrating another illustrative embodiment of a workflow 1600 for forming an undercut etch resistant mask on a substrate in accordance with the present invention. At 1602, an anti-corrosion layer (such as, for example, anti-corrosion layer 629, 729, 829, 929, 1129, 1229, or 1329) is formed over the substrate having the unpatterned device layer. Carpet coating. At 1604, a patterned etch mask (such as, for example, etch mask 628, 728, 828, or 928) is prepared over the unpatterned corrosion-resistant coating.

FIG. 17 is a flowchart illustrating another illustrative specific example of the workflow 1700 of the forming device according to the present invention. At 1702, an unpatterned device layer, such as, for example, but not limited to, a copper film, is laminated to the electrically insulating surface of the substrate. At 1704, a blanket coating of an anti-corrosion layer (such as, for example, anti-corrosion layer 629, 729, 829, 929, 1129, 1229, or 1329) is formed over the copper film. At 1706, an etch mask (such as, for example, a resist) is prepared by printing a liquid resist ink in a desired pattern over the blanket-coated corrosion-resistant material and then drying the liquid to form the etch mask. agent mask 628, 728, 828, or 928). At 1708, a spray-type wet etch is performed to etch areas of the copper film not covered by the etch mask material. At 1710, the etch mask is stripped from the remainder of the copper film to expose the formed conductive features. In various embodiments, the anti-corrosion layer is a primer layer, and the liquid resist ink can be applied to the surface in the form of droplets delivered by an inkjet nozzle, and upon contact with the primer surface, such droplets Can effectively stop moving or "freeze" in place for a short period of time (e.g., on the order of microseconds), such as, but not limited to, caused by a chemical reaction triggered by the interaction between the resist ink and the primer layer, causing the ink droplets to settle on the primer surface Further displacement or diffusion is greatly reduced or completely stopped, as described above and described in International Publication Nos. WO2016/193978 A2 and WO2016/025949 A1. In various embodiments, a primer layer and a liquid etch mask ink interact to form a two-component etch mask material.

Figure 18 shows a block diagram of an apparatus 1800 for generating a device in accordance with an embodiment of the present invention. Device 1800 may include housing 1802. In various illustrative embodiments, housing 1802 may be configured to provide ambient particle filtration, relative humidity control, temperature control, or other process condition control within the processing environment. The apparatus 1800 may include a first substrate transfer mechanism 1804, and a substrate input unit 1806 configured to receive substrates from the first substrate transfer mechanism 1804. The substrate may include an unpatterned device layer, such as substrate 602, 702, 802, or 902 discussed in connection with Figures 6A-9C, and unpatterned device layer 604, 704, 804, or 904. The first deposition module 1808 is configured to deposit a first layer, such as the corrosion-resistant layers 629, 729, 829, 929, 1129, 1229, discussed in connection with Figures 6A-9C and 11-13C over the unpatterned device layer. Or 1329, wherein the first deposition module 1808 may include a portion for depositing the first material onto the substrate and a portion for further processing the deposited first material to form the anti-corrosion layer, such as, but not limited to, by drying, curing , or otherwise process the first material. The second deposition module 1812 is configured to deposit an etch mask, such as the etch mask 628, 728, 828, or 928 discussed in connection with Figures 6A-9D, over a layer of corrosion-resistant material. The second deposition module 1812 may include a portion for depositing a second material onto a substrate and a portion for further processing the deposited second material to form the etch mask, such as, but not limited to, by drying, curing, developing, exposing , laser direct writing, or otherwise process the secondary material. The apparatus 1800 may include a substrate output unit 1820 that provides the substrates to a second substrate transfer mechanism (not shown). A first substrate transfer mechanism 1804 can transfer substrates from a previous processing module or device to device 1800, and a second substrate transfer mechanism can transfer substrates to a next processing module or device.

In various illustrative embodiments, first deposition module 1808 and second deposition module 1812 may be configured to deposit materials by methods such as inkjet printing, spraying, lamination, spin coating, or any other deposition method. , including but not limited to the deposition methods described above.

In some illustrative embodiments, the apparatus includes a substrate cleaning module 1807 configured to receive a substrate from a substrate input unit 1806, clean the substrate, and transfer the substrate to a first deposition module 1808. In some illustrative embodiments, first deposition module 1808 and second deposition module 1812 may be a single module. In some illustrative embodiments, apparatus 1800 includes an etch module 1816 configured to etch material in an unpatterned device layer that is not protected by an etch mask; and a stripping module 1818 configured to etch a substrate The etch mask is removed from the substrate after the material on the unpatterned device layer is removed.

Figure 19 illustrates an exemplary workflow 1900 in accordance with another specific example of the present invention. At 1902, a primer layer including a first reactive component is applied to an unpatterned device layer, such as a metallic surface, such as copper foil. The primer layer may be an anti-corrosion layer, such as anti-corrosion layer 629, 729, 829, 929, 1129, 1229, or 1329 in connection with the specific examples above. At 1904, a two-component resist mask is prepared by image-printing a liquid resist ink containing a second composition, including a second reactive component, onto the primer layer. The two-component material resulting from the interaction of the resist ink may comprise, for example, an etch mask such as 628, 728, 828, or 928, as described in conjunction with the specific examples above. The second composition may include a second reactive component capable of chemically reacting with the first reactive component. In various embodiments, the resist ink may be applied to the surface in the form of droplets delivered by an inkjet nozzle, and such droplets may be effectively stopped within a short time (e.g., on the order of microseconds) upon contact with the primer surface Move or "freeze" into place, such as, but not limited to, resulting from a chemical reaction triggered by the interaction between the resist ink and the primer layer, such that further displacement or spreading of the ink droplets across the primer surface is greatly reduced or eliminated Stop, as described above and described in International Publication Nos. WO2016/193978 A2 and WO2016/025949 A1. At 1906, before or during the etching process, unmasked portions of the primer layer (ie, portions of the primer layer not covered by the etch mask) are removed. At 1908, the unmasked portions of the metallic surface are etched to form a patterned device layer, such as patterned device layer 630, 730, 830, 930, 1130, 1230, or 1330 discussed in connection with the specific examples above. At 1910, the resist mask is removed to expose the patterned device layer. Example 1-3

The following comparative examples were performed to demonstrate the reduction in undercut achieved using embodiments of the present invention compared to conventional methods that do not use corrosion-resistant materials.

In Examples 2 and 3 detailed below, the polyimine-based reagent composition was first applied onto an FR4 copper-clad laminate with a ½ Oz (17 µm) copper thickness using an Epson stylus 4900 inkjet printer. A resist mask is then applied over the polyimide layer. Used 10% propylene glycol as humectant, 1% (w/w) 2-amino-2-methylpropanol as ion exchanger, 0.3% (w/w) BYK supplied as surfactant 348 and 2% (w/w) Bayscript BA Cyan as colorant to prepare aqueous resist compositions. The resist solution also included a 24% Joncryl 8085 styrene acrylic resin solution as an anionic resist. In the following description, % (w/w) is a measure of concentration of a substance in terms of weight percent relative to the weight of the composition. The printed samples were dried at 80°C. The copper from the unprotected exposed areas is etched away using an etchant bath containing an acidic etching solution. The resist mask was stripped by immersing the etched plate in a 1% (w/w) aqueous NaOH solution at 25°C, then washing the FR4 copper plate with water and air drying at 25°C. In Example 1, another sample was prepared without applying an underlying agent layer.

Example 1: A resist pattern was printed on an uncoated copper FR4 board with ½ Oz (17 µm) copper thickness using an Epson stylus 4900 inkjet printer. Referring to Figure 20, a photomicrograph of a cross-section of a copper wire sample fabricated according to Example 1 is shown. Used 10% propylene glycol as humectant, 1% (w/w) 2-amino-2-methylpropanol as ion exchanger, 0.3% (w/w) BYK supplied as surfactant 348 and 2% (w/w) Bayscript BA Cyan as colorant to prepare aqueous resist compositions. The resist solution also included a 24% solution of Joncryl 8085 styrene acrylic resin as the anionic resist reactive component. Resist drying, etching and removal were performed as described above. As can be seen in Figure 20, the slope of the copper sidewalls is relatively high. The relative dimensions of the formed conductive features were measured and the etch factor was calculated to be 1.5.

Example 2: Printing a resist pattern on a copper FR4 plate coated with polyimide coating. The polyimine aqueous solution was prepared into a 10% (w/w) LUPASOL G100 (polyethyleneimine with 5000 molecular weight) aqueous solution supplied by BASF, 10% (w/w) propylene glycol, 10% n-propanol and 0.3% (w/w) Mixture of TEGO 500 supplied by Evonik Industries. The polyimide solution was applied using an Epson stylus 4900 inkjet printer. The polyimine-based coating was left to dry at room temperature, resulting in a completely transparent uniform coating with a dry thickness of 0.075 μm that covered the entire surface of the plate without crystal formation. The resist composition was printed on the coated copper plate using the methods and materials detailed above. The relative dimensions of the formed conductive features were measured and the etch factor was calculated to be 2.5.

Example 3: Printing a resist pattern on a copper FR4 plate coated with polyimide coating. Referring to FIG. 21 , a photomicrograph of a cross-section of a copper wire sample manufactured according to Example 3 is shown, in accordance with a specific example of the present invention. The polyimide coating was applied to the FR4 board using an Epson stylus 4900 inkjet printer. A polyimine solution was prepared as 10% (w/w) LUPASOL HF (polyethyleneimine with a molecular weight of 25,000), 10% (w/w) propylene glycol, 10% n-propanol and 0.3% ( w/w) TEGO 500 aqueous solution mixture supplied by Evonik Industries. The coated plates were left to dry at room temperature, resulting in a completely transparent uniform coating with a dry layer thickness of 0.075 μm that covered the entire surface without crystal formation.

The resist composition was prepared as detailed in Example 1. Etching of the unmasked copper and removal of the resist mask were performed as described for Example 1. As shown in Figure 21, the slope of the sidewalls of the copper lines is much smaller than that of the sample prepared without the undercut elimination layer as shown in Figure 20. The relative dimensions of the formed conductive features were measured and the etch factor was measured and found to be 7.5.

Table 1 below summarizes some characteristics of the results of the three examples.

Table 1 Example Undercut prevention agent MW W2-W1 X Height-H Etch factor 1 without - 20 10 15 1.5 2 Lupasol G100 5000 12 6 15 2.5 3 Lupasol HF 25,000 4 2 15 7.5

The following comparative examples were performed to demonstrate improvements in forming an etch mask using a primer layer and an inkjet printed resist ink, wherein upon contact with the primer layer, there is between the components of the primer layer and the resist ink One or more reactions occur, thereby forming a two-component etch mask material, and droplets of resist ink rapidly (e.g., on the order of microseconds) cease to move or freeze, and subsequent spreading and/or displacement of such droplets greatly reduced. Example 4-12

The exemplary resist composition (described herein as the second composition) was printed on FR4 copper clad laminates with thicknesses of 1/2 Oz, 1/3 Oz and 1 Oz using an Epson stylus 4900 inkjet printer. In some cases, an Epson stylus 4900 inkjet printer is first used to coat copper with an immobilizing composition (described herein as the first composition), thereby forming an immobilizing layer on which resist is selectively printed according to a predetermined pattern. Corrosion composition. In the following description, % (w/w) is a measure of concentration of a substance in terms of weight percent relative to the weight of the composition. The copper from the exposed areas not protected by the resist was etched away using an etchant bath containing a 42° Baume ferric chloride etchant solution [pernix 166] supplied by Amza. Etching was performed in a Spray Developer S31 supplied by Walter Lemmen GMBH at a temperature of 35°C for 3 minutes. The resist mask was stripped by immersing the etched plate in a 1% (w/w) aqueous NaOH solution at 25°C, then washing the FR4 copper plate with water and drying by air at 25°C. In some experiments, copper plates were also etched using industrial etching units including advanced and ultra-advanced etching units, manufactured by Universal or Shmidth, which contain a copper chloride solution for etching unprotected copper.

Example 4: Resist composition printed on uncoated copper FR4 board (comparative data). Prepared with 10% propylene glycol and 1% (w/w) 2-amino-2-methylpropanol, 0.3% (w/w) BYK 348 and 2% (w/w) Bayscript BA Cyan supplied by BYK Resist composition (second composition). These materials were dissolved in water containing a 24% solution of Joncryl 8085 styrene acrylic resin as the anionic reactive component. The resist composition was printed on an FR4 copper-clad board with ½ Oz thickness using an Epson stylus 4900 inkjet printer to create a resist mask. Dry resist thickness is 5 microns.

The etch mask was visually inspected and the printed pattern showed very poor print quality with extremely poor edge resolution, broken lines, and severe shorts between lines.

Example 5: A resist composition was prepared as detailed in Example 4. The primer or fixing composition is prepared as 10% (w/w) LUPASOL PR8515 (polyethylenimine as cationic reactive component), 10% (w/w) propylene glycol, 10% n-propylene supplied by BASF Alcohol and an aqueous solution containing 0.3% (w/w) TEGO 500 (defoaming substrate wetting additive) supplied by Evonik Industries.

An Epson stylus 4900 inkjet printer was used to coat the FR4 copper plate. The coated plates were left to dry at room temperature, resulting in a completely transparent uniform coating with a dry layer thickness of 0.3 μ that covered the entire surface without any crystal formation. The resist composition was printed on the coated copper plate using an Epson stylus 4900 inkjet printer and dried at 80°C to create a two-component resist mask. Visual inspection of the etch mask showed better print quality than Example 4, but still relatively poor print quality with widened lines and shorts between lines. Etching of unmasked copper and removal of the resist mask was performed as detailed in Example 4. The resulting wiring pattern after the etching process has the same image as the resist mask with the same widened lines and shorts between lines. It should be noted that for some applications the print quality exhibited by Example 5 may be sufficient.

Example 6 - A resist composition was prepared as detailed in Example 4. The immobilization composition was prepared as detailed in Example 5, except that 0.3% (w/w) TEGO 500 was replaced with 0.3% (w/w) TEGO 500 containing 13% (w/w) concentrated HCl.

An FR4 copper plate was coated with the immobilized composition using an Epson stylus 4900 inkjet printer and dried to form a coating as detailed in Example 5. Similar to Example 5, the resist composition was inkjet printed on the coated copper plate and dried at 80°C to create a two-component resist mask. The resist pattern exhibits high print quality, with well-defined fine lines with thicknesses as low as 2 mm, clear edges and no breaks. Etching of unmasked copper and removal of the resist mask was performed as detailed in Example 4. The wiring pattern produced by the etching and stripping process exhibits a well-defined pattern with fine lines with widths as low as 15 microns, clear edges, and no breaks.

Example 7 - Two-component reaction to print a resist composition on a copper surface coated with a reactive cationic composition containing hydrochloric acid (HCl). The resist composition was prepared as detailed in Example 4. The immobilization composition is prepared as

A mixture of 10% (w/w) Styleze W-20 (supplied by ISP as a 20% aqueous polymer solution), 0.1% BYK 348, and 13% (w/w) concentrated HCl in water.

A Mayer rod was used to cover the F4F copper plate with the immobilization composition to create a dry layer with a thickness of 0.4 μ. The coated panels were left to dry, resulting in a completely transparent coating over the entire copper surface with no crystals forming. Similar to Example 5, the resist composition was inkjet printed on the coated copper plate and dried at 80°C to create a two-component resist mask.

The resist pattern exhibits high print quality with well-defined and fine lines as low as 2 mm with sharp edges and no breaks. Residues of the immobilized layer not covered by the resist composition were washed by soaking the plate in water for 2 minutes at a temperature of 25°C and dried at 80°C. Etching to expose copper and removal of the resist mask was performed as detailed in Example 4. The wiring pattern on this board exhibits well-defined fine lines with widths as low as 2 mils, crisp edges, and no breaks.

Example 8 - Two-component reaction to print a resist composition on a copper surface coated with a reactive cationic composition containing hydrochloric acid (HCl). The resist composition was prepared as detailed in Example 4. will be fixed

The composition was prepared as a mixture of 10% (w/w) Lupasol HF (supplied by BASF as a 56% aqueous polymer solution), 0.1% aqueous BYK 348 containing 13% (w/w) concentrated HCl.

A Mayer rod was used to cover the FR4 copper plate with the immobilization composition to create a dry layer with a thickness of 1 μ. The coated panels were left to dry, resulting in a completely transparent coating over the entire copper surface with no crystals forming. Similar to Example 5, the resist composition was inkjet printed on the coated copper plate and dried at 80°C to create a two-component resist mask.

The resist pattern showed high print quality with well-defined fine lines as low as 2 mil with clear edges and no breaks. Residues of the immobilized layer not covered by the resist composition were washed by soaking the plate in water for 3 minutes at a temperature of 25°C and dried at 80°C. Etching to expose copper and removal of the resist mask was performed as detailed in Example 4. The wiring pattern on this board exhibits well-defined fine lines with widths as low as 2 mils, crisp edges, and no breaks.

Example 9 - Two-component reaction: A resist composition was printed on a copper surface coated with a reactive cationic composition containing hydrochloric acid (HCl). The resist composition was prepared as detailed in Example 5. The immobilization composition was prepared as a mixture of 10% (w/w) Lupasol PN50 (supplied by BASF as a 49% aqueous polymer solution), 0.1% aqueous BYK 348 containing 13% (w/w) concentrated HCl.

A Mayer rod was used to cover the FR4 copper plate with the immobilization composition to create a dry layer with a thickness of 1 μ. The coated panels were left to dry, resulting in a completely transparent coating over the entire copper surface with no crystals forming. Similar to Example 5, the resist composition was inkjet printed on the coated copper plate and dried at 80°C to create a two-component resist mask.

The resist pattern exhibits high print quality, with well-defined and thin lines as low as 2 mm with clear edges and no breaks. The residue of the immobilized layer was washed as detailed in Example 8. Etching to expose copper and removal of the resist mask was performed as detailed in Example 1. The wiring pattern on this board exhibits well-defined fine lines with widths as low as 2 mils, crisp edges, and no breaks.

Example 10 - Two-component reaction, resist composition printed on copper surface coated with reactive composition containing citric acid. The resist composition was prepared as detailed in Example 4. The immobilization composition was prepared as an aqueous solution mixture of 10% (w/w) citric acid, 25% (w/w) propylene glycol, containing 0.3% (w/w) TEGO 500 (defoaming substrate moisturizer) supplied by Evonik Industries. wet additive).

An Epson stylus 4900 inkjet printer was used to coat FR4 copper plates with this immobilizing composition. The coated plates were left to dry at room temperature, resulting in a completely transparent uniform coating with a dry layer thickness of 0.3 μ that covered the entire surface without crystal formation. Similar to Example 5, the resist composition was inkjet printed on the coated copper plate and dried at 80°C to create a two-component resist mask.

The resist pattern showed high print quality with well-defined fine lines as low as 2 mil with clear edges and no breaks. Etching to expose copper and removal of the resist mask was performed as detailed in Example 4. The wiring pattern on this board exhibits well-defined fine lines with widths as low as 2 mils, crisp edges, and no breaks.

Example 11 - Two-Component Reaction A coating composition containing a resist composition was prepared as detailed in Example 4. The immobilization composition was prepared into 2.5% (w/w) Zn (NO ₃ ) ₂ , 3.75% (w/w) calcium acetate, 0.2% (w/w) Capstone 51, 5% (w/w) n-propyl Alcohol and 5% (w/w) Lupasol FG (supplied by BASF) in water.

A Mayer rod was used to cover the FR4 copper plate with the immobilization composition to create a dry layer with a thickness of 0.5 μ. The coated panels were left to dry, resulting in a completely transparent coating over the entire copper surface with no crystals forming. Similar to Example 5, the resist composition was inkjet printed on the coated copper plate and dried at 80°C to create a two-component resist mask.

Similar to Example 5, the resist composition was inkjet printed on the coated copper plate and dried at 80°C to create a two-component resist mask.

The resist pattern showed high print quality with well-defined fine lines as low as 2 mil with clear edges and no breaks. Etching to expose copper and removal of the resist mask was performed as detailed in Example 4. The wiring pattern on this board exhibits well-defined fine lines with widths as low as 2 mils, crisp edges, and no breaks.

Example 12 - Resist composition prepared as 8% (w/w) PVA, 24% Joncryl 8085 styrene acrylic resin solution (supplied as 42% aqueous polymer solution) and 1.5% 2-amino-2-methyl A mixture of aqueous solutions of propanol.

The immobilization composition was prepared as follows: 2 % (w/w) of Basacid Red 495, 10% (w/w) propylene glycol, 10% n-propanol, 0.3% (w/w) TEG0500, 10% (w/w) Lupasol G20 (supplied by BASF) containing 12% (w/w) concentrated HCl. A Mayer rod was used to cover the FR4 copper plate with the resist composition to create a dry layer with a thickness of 2.4 μ. The coated panels were left to dry, resulting in a completely transparent coating over the entire copper surface with no crystals forming. The immobilization composition was inkjet printed onto the coated copper plate and dried at 80°C to create a two-component resist mask.

[0053] Similar to Example 5, the resist composition was inkjet printed on the coated copper plate and dried at 80°C to create a two-component resist mask.

The resist pattern showed high print quality with well-defined fine lines as low as 2 mil with clear edges and no breaks. Residues of the coating not covered by the resist ink were washed by soaking the plates in 1% (w/w) _NaHCO3 in water for 30 seconds at 25°C and dried at 80°C. Etching to expose copper and removal of the resist mask was performed as detailed in Example 4. The wiring pattern on this board exhibits well-defined fine lines with widths as low as 2 mils, crisp edges, and no breaks. Cationic compositions (immobilized reactive components)

Non-limiting examples of cationic reactive components (immobilized reactive components) may include polyamides such as polyethyleneimine, divalent metal salts, organic or inorganic acids, heteropolymers of vinylpyrrolidone, dimethyl Aminopropylmethacrylamide; methacrylamidepropyllauryldimethylammonium chloride, polyquaternary amines and polyamines in their natural form or as ammonium salts.

The thickness of the dried immobilized layer can be as thin as about 0.01 microns. Typical desired thickness of the dry layer can vary between 0.025 and 5 microns.

The cationic composition (first composition) may include additional components adapted to the application method and the desired width of the dry layer. The composition may have a viscosity suitable for spraying or inkjet printing, such as a viscosity of less than 60 centipoise or between 3 and 20 cP (centipoise) respectively at ambient temperature. If a different application method is used, the composition may have a higher viscosity.

In some embodiments, an acidic solution may be added to the first solution to increase the reactivity of the first layer to the copper layer 320 and its reactivity to the resist or immobilization layer. In some embodiments, the first layer may be further developed, such as by water, prior to the copper etching process. In some embodiments, the applied first layer can be dried before the second layer is applied. The initially dry layer may contain primarily the first reactive material. The first layer can be dried using any known drying method.

Some non-limiting examples of first reactive components (eg, immobilized components) and first compositions (eg, immobilized compositions, cationic compositions) are listed in Table 1. Table 1: immobilized composition reactive component chemical group 1 Aqueous solution: 10% (w/w) polyethyleneimine, 10% (w/w) propylene glycol, 10% n-propanol, containing 0.3% (w/w) surfactant Polyethyleneimine, 10% (w/w) Molecular weight (Mw) 500-5000 2 Aqueous solution: 10% (w/w) polyethyleneimine, propylene glycol, 10% n-propanol, containing 0.3% (w/w) surfactant Polyethyleneimine, 10% (w/w) Mw 6000-2000000 3 Aqueous solution: 10% (w/w) VP heteropolymer, 10% (w/w) propylene glycol, 10% n-propanol, containing 0.3% (w/w) surfactant Heteropolymer of vinylpyrrolidone, dimethylaminopropylmethacrylamide & methacrylamidepropyllauryldimethylammonium chloride 4 Aqueous solution: 10% (w/w) polyquaternary amine, 10% (w/w) propylene glycol, 10% n-propanol, containing 0.3% (w/w) surfactant polyquaternaryamine 5 Aqueous solution: 3% (w/w) polyethyleneimine, 5% metal salt, 10% (w/w) propylene glycol, 10% n-propanol, containing 0.3% (w/w) surfactant Polyethyleneimine (Mw 500-5000) contains divalent metal salts (such as Ca, Zn, Mg, etc.) 6 Aqueous solution: 3% (w/w) polyethyleneimine, 5% metal salt, 10% (w/w) propylene glycol, 10% n-propanol, containing 0.3% (w/w) surfactant Polyethyleneimine (Mw 600-2000000) contains divalent metal salts (Ca, Zn, Mg, etc.) Anionic composition (resist polymerizable component)

In some embodiments, the second reactive component (eg, polymeric component) may be an etch-resistant component (resistant to metallic etching solutions). The second reactive component may include polyanionic reactive groups such as: acrylates, styrene acrylates; phosphates and sulfonates. A droplet of etch-resistant ink applied on the first (eg, immobilized) layer may stop due to a chemical reaction between the first reactive material (which includes polycations) and the second reactive material (which includes polyanions) Moves and immobilizes onto copper surface. Since immobilization is very rapid (in the microsecond range), the dimensions of the printed pattern are similar to those of the desired pattern. The compound formed by the reaction of the first reactive material and the second reactive material (both of which are soluble in water) should be insoluble in the copper etching solution.

The second composition may have a viscosity suitable for inkjet printing of less than 60 cP, such as 3-20 cP, at the jetting temperature. If a different application method is used, the composition may have a higher viscosity. In some embodiments, the second composition may include no more than 20% (w/w) of reactive components to maintain the desired viscosity. In some embodiments, the polyanionic reactive component (resist polymer) can have a maximum molar weight of 5000 when dissolved in the composition (eg, the polymer can have relatively short chains). In some embodiments, the resist polymer may have a higher molar weight, such that the composition is in the form of a polymer emulsion or dispersion. The second reactive component may have a high acid number, for example, more than 100 reactive anionic groups per gram of polymer. For example, resist polymers according to specific examples of the invention may have more than 200, 240, 300 or more reactive anionic groups in each chain.

Some non-limiting examples of second reactive components (anti-etch components) and second compositions (anti-etch compositions, anionic compositions) are listed in Table 2. Table 2: No. Anti-etching composition Second reactive component 1 Dissolve 2% (w/w) Cyan dye, 10% propylene glycol, 1% (w/w) 2-amino-2-methylpropanol and 0.3% (w/w) surfactant in a solution containing 24% benzene. Ethylene acrylic resin solution in water. Acrylate Mw 800-17,000 Acid Number in solution or emulsion 130-240 2 Dissolve 2% (w/w) Cyan dye, 10% propylene glycol, 1% (w/w) 2-amino-2-methylpropanol and 0.3% (w/w) surfactant in 24% phosphoric acid Ester resin solution in water. Organophosphate Mw 800-17,000 Acid value 130-240 in solution or emulsion 3 Dissolve 2% (w/w) Cyan dye, 10% propylene glycol, 1% (w/w) 2-amino-2-methylpropanol and 0.3% (w/w) surfactant in a solution containing 24% sulfonate. acid ester resin solution in water. Organic sulfonate Mw 800-17,000 Acid value 130-240 in solution or emulsion

The descriptions and drawings illustrating illustrative specific examples are not to be considered limiting. Various mechanical, compositional, structural and operational changes, including equivalents, may be made without departing from the scope of the specification and patent claims. In some instances, well-known structures and techniques have not been shown or described in detail so as not to obscure the present invention. The same numbers in two or more figures represent the same or similar elements. Furthermore, elements and their associated features described in detail with reference to one specific example may in any practical case be included in other specific examples not specifically shown or described. For example, if an element is described in detail with reference to one specific example and the element is not described with reference to a second specific example, it may nevertheless be claimed that the element is included in the second specific example.

For the purposes of this specification and the appended claims, all numbers expressing amounts, percentages, or ratios and other numerical values used in the specification and appended claims are to be understood in all cases (if they not yet modified) is modified by the word "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending on the desired properties sought to be obtained. At a minimum, and without any attempt to limit the application of the doctrine of equality to the patentable scope, each numerical parameter should at least be construed in light of the number of significant digits shown and by applying ordinary rounding techniques.

It should be noted that, as used in this specification and the appended claims, the singular forms "a/an" and "the" and any use of the singular form of any word include plural referents unless Define a referent clearly and unambiguously. As used herein, the word "include" and its grammatical conjugations are intended to be non-limiting, such that recitation of an item in a list is not to the exclusion of other similar items that may be substituted or added to the listed item.

Furthermore, the technical terms used in this specification are not intended to limit the present invention. For example, you can use spatially relative terms - such as "beneath", "below", "lower", "above", "above" "High", "close to", etc. are used to describe the relationship of one element or feature to another element or feature illustrated in the drawings. These spatially relative terms are intended to cover different positions (ie, positioning) and orientations (ie, rotational arrangements) of the device in use or operation, in addition to the position and orientation illustrated in the drawings. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "above" the other elements or features. Thus, the exemplary phrase "below" can encompass both upper and lower positions and orientations. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Further modifications and alternative embodiments will be apparent to those skilled in the art in view of the invention herein. For example, apparatus and methods may include additional components or steps that are omitted from the figures and descriptions for clarity of operation. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching one skilled in the art the general manner of carrying out the present teachings. It is to be understood that the various specific examples shown and described herein are to be considered as illustrative. Components and materials and arrangements of such components and materials may be substituted by those illustrated and described herein, parts and steps in workflows and methods may be in an alternating order, and certain features of the present teachings may be utilized independently, for This will be apparent to those skilled in the art having the benefit of the description herein. Changes may be made in the elements described herein without departing from the spirit and scope of the present teachings and appended claims.

Although various illustrative embodiments herein describe the fabrication of PCBs, those skilled in the art will understand that other electrical and optical devices or components fabricated using similar etching and metal or conductive line patterning techniques are also contemplated herein. Within the scope of the invention and patent application, PCB is discussed as a non-limiting illustrative application. Other devices and components that may be fabricated according to the illustrative embodiments herein include, but are not limited to, microchips, electronic displays, microchips, solar cells, and other electronic, optical, or other devices and components.

It is to be understood that the specific examples and specific examples set forth herein are not limiting and that the structures, dimensions, materials, and methods may be modified without departing from the scope of the present teachings. Other embodiments in accordance with the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention. It is intended that the specification and examples be considered illustrative only and that the scope of the following claims be accorded its fullest breadth under applicable law, including equivalents.

100:Device 102:Substrate 104: Unpatterned device layer 106:Etching mask 108: Any pattern you want 110: Exposed surface 112:Non-vertical side wall 114: Patterned device layer 200:Device 202:Substrate 204: Unpatterned device layer 206:Patterned etching mask 208:Pattern 216: Unpatterned resist layer 300:Device 302:Substrate 304: Unpatterned device layer 306: Etch mask 308: Any pattern you want 400:Device 402:Substrate 404: Unpatterned device layer 405: Partially patterned device layer 406: Etch mask 408:Pattern 410: Top surface 412:Side wall 414: Patterned device layer 418:Chemical Etchants 420: Container 500:Device 504: Unpatterned device layer 505: Partially patterned device layer 506: Etch mask 512:Side wall 514: Patterned device layer 518: Etchants 520: Container 522:Jet 600:Device 602:Substrate 604: Unpatterned device layer 608:Pattern 628: Etch mask 629: Anti-corrosion layer 630: Patterned device layer 632:Tapered sidewall 700:Device 702:Substrate 704: Unpatterned device layer 705: Partially patterned device layer 718: Etchants 720: Container 728:Etch mask 729: Anti-corrosion layer 730: Patterned device layer 732:Side wall 800:Device 802:Substrate 804: Unpatterned device layer 805: Partially patterned device layer 822:Jet 828:Etch Mask 829: Anti-corrosion layer 830: Patterned device layer 832:Side wall 900:Device 902:Substrate 904: Unpatterned device layer 918: Etchants 920: Container 928:Etch mask 929: Anti-corrosion layer 930: Patterned device layer 932:Side wall 1100:Device 1102:Substrate 1128:Etch mask 1129: Anti-corrosion layer 1200:Device 1202:Substrate 1205: Partially patterned device layer 1218: Etchants 1232:Side wall 1246: Anti-corrosion material part 1300:Device 1305: Partially patterned device layer 1318: Etchants 1329: Anti-corrosion material layer 1332:Side wall 1348:Separated particles 1400:Workflow 1402-1408: Steps 1500:Workflow 1502-1508: Steps 1600:Workflow 1602-1604: Steps 1700:Workflow 1702-1710: Steps 1800:Equipment 1802: Shell 1804: First substrate transfer mechanism 1806:Baseboard input unit 1807:Substrate cleaning module 1808: The first deposition module 1812: Second deposition module 1816:Etching module 1818: Strip module 1820:Baseboard output unit 1900:Exemplary workflow 1902-1910: Steps W1: first feature width/top part width W2: Second feature width/base portion width W3: Width X:(W2-W1)/2 H: line height

[FIGS. 1A-1D] Show cross-sectional views and plan views of an apparatus undergoing a conventional method for forming a patterned layer on a substrate.

[Figs. 2A-2C] A cross-sectional view and a plan view showing an apparatus undergoing another conventional method for forming a patterned layer on a substrate.

[Figs. 3A and 3B] A cross-sectional view and a plan view showing an apparatus undergoing another conventional method for forming a patterned layer on a substrate.

[Figs. 4A-4C] A cross-sectional view and a plan view showing an apparatus undergoing another conventional method for forming a patterned layer on a substrate.

[Figs. 5A-5C] Show cross-sectional views, plan views, and perspective views of an apparatus undergoing another conventional method for forming a patterned layer on a substrate.

[Figs. 6A-6D] illustrate cross-sectional views and plan views of an apparatus undergoing a method for forming a patterned layer on a substrate according to an exemplary embodiment of the present invention.

[Figs. 7A-7C] A cross-sectional view and a plan view showing a device undergoing a method for forming a patterned layer on a substrate according to another exemplary embodiment of the present invention.

[Figs. 8A-8D] illustrate cross-sectional views and plan views of an apparatus undergoing a method for forming a patterned layer on a substrate according to another exemplary embodiment of the present invention.

[Figs. 9A-9C] A cross-sectional view and a plan view showing a device undergoing a method for forming a patterned layer on a substrate according to another exemplary embodiment of the present invention.

[Fig. 10] A cross-sectional view showing an apparatus for forming a patterned layer on a substrate during processing according to a conventional method.

[Fig. 11] A cross-sectional view showing an apparatus for forming a patterned layer on a substrate during processing according to an exemplary embodiment of the present invention.

[Fig. 12A] is a cross-sectional view of an apparatus for forming a patterned layer on a substrate during processing according to an exemplary embodiment of the present invention.

[FIG. 12B] is an enlarged view of the part circled 12B in FIG. 12A.

[Fig. 13A] is a cross-sectional view of an apparatus for forming a patterned layer on a substrate during processing according to another exemplary embodiment of the present invention.

[Fig. 13B and Fig. 13C] are enlarged views of the portions in circles 13B and C of Fig. 13A, showing the representation of different states in B and C.

[Fig. 14] is a flowchart showing a workflow for forming a patterned layer on a substrate according to an exemplary embodiment of the present invention.

[Fig. 15] is a flowchart showing a workflow for forming a patterned layer on a substrate according to another exemplary embodiment of the present invention.

[Fig. 16] is a flowchart showing a workflow for forming a patterned layer on a substrate according to another exemplary embodiment of the present invention.

[Fig. 17] is a flowchart showing a workflow for forming a patterned copper layer on a substrate, for example, in the manufacture of a PCB according to another exemplary embodiment of the present invention.

[Fig. 18] is a block diagram showing system components for forming a device according to various illustrative embodiments of the present invention.

[Fig. 19] is a flowchart showing a workflow for forming a patterned layer on a substrate according to another exemplary embodiment of the present invention.

[Fig. 20] is a photomicrograph of conductive features formed according to a conventional method.

[Fig. 21] is a photomicrograph of a conductive feature formed according to an illustrative embodiment of the present invention.

For simplicity and clarity of illustration, elements shown in the figures are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Furthermore, where appropriate, element symbols may be repeated in the drawings to indicate corresponding or similar elements.

600:Device

602:Substrate

604: Unpatterned device layer

608:Pattern

628: Etch mask

629: Anti-corrosion layer

630: Patterned device layer

632:Tapered sidewall

Claims (20)

A method of fabricating a device patterned with one or more conductive features, the method comprising: forming a first layer including a first reactive component over the conductive layer of the substrate; forming a second layer in contact with the first layer, the second layer comprising a second reactive component, the first reactive component and the second reactive component reacting upon contact to pattern the etching mask, Thereby obtaining a covered portion of the conductive layer and an exposed portion of the conductive layer, the covered portions being disposed at locations corresponding to one or more conductive features of the device; performing a wet etching process to form the conductive features by removing the exposed portions of the conductive layer from the substrate; and removing the etch mask to expose the conductive features of the device, Wherein the first reactive component, the second reactive component or both comprise an imine group, an azole group, a hydrazine group, an amino acid, a Schiff base, or a combination thereof. For example, the method of claim 1, wherein the first layer includes a polymer. For example, according to the method of claim 1, the first layer includes organic materials. For example, the method of claim 3, wherein the organic material contains one or more imine groups. For example, the method of claim 3, wherein the organic material contains one or more amine groups. For example, the method of claim 3, wherein the organic material contains one or more azole groups. For example, the method of claim 3, wherein the organic material contains one or more hydrazine groups. For example, the method of claim 3 of the patent scope, wherein the organic material contains amino acids. For example, the method of claim 3 of the patent scope, wherein the organic material contains Schiff base. The method of claim 1, wherein forming the second layer includes depositing a blanket coating of the second layer in contact with the first layer. For example, the method of claim 1, wherein forming the second layer includes using at least one of inkjet printing, slot coating, spin coating, or lamination. For example, the method of claim 1, wherein forming the first layer includes using at least one of inkjet printing, slot coating, spin coating, or lamination. For example, according to the method of claim 1, the first layer and the second layer are each formed by inkjet printing. A method that contains: forming a first layer including a first reactive polymer over the conductive layer of the substrate; forming a second layer in contact with the first layer, the second layer comprising a second reactive organic polymer, wherein the first layer, the second layer, or both form a pattern, and wherein the first reactive polymer and the second reactive polymer reacts upon contact to form a patterned etch mask; removing unreacted portions of the first layer, the second layer, or both to expose the conductive layer; and performing a wet etching process to form conductive features by removing exposed portions from the conductive layer, wherein the first reactive polymer, the second reactive polymer, or both comprise imine groups, azole groups, hydrazine groups, amino acids, phosphate groups, sulfonic acid groups, or Schiff Base, or combination thereof. For example, the method of claim 14, wherein forming the first layer, the second layer or both includes inkjet printing. For example, the method of claim 14, wherein the first layer is blanket-coated over the conductive layer of the substrate, and the second layer forms a pattern. For example, according to the method of claim 16, the thickness of the first layer is 5 μm to 40 μm. For example, the method of claim 14, wherein the first layer, the second layer, or both contain a surfactant. For example, the method of claim 14, wherein the first layer is formed of an aqueous material containing acid. The method of claim 14, wherein the first layer is formed as a liquid material and dried before forming the second layer.

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