KR100760197B1 - Method of forming a masking pattern on a surface - Google Patents

Abstract

A method of forming a masking pattern on a surface using the technique of liquid droplet injection to deposit a liquid drop of deposition material, the method comprising forming a pattern comprising multiple discrete or coalescing elongated portions on the surface. Depositing a plurality of liquid droplets.

Mask Patterns, Etching, Printheads

Description

Method of forming a masking pattern on the surface {METHOD OF FORMING A MASKING PATTERN ON A SURFACE}

The present invention relates to a method of forming a mask pattern on a surface. In one preferred embodiment, the present invention uses a computer-generated image file (ie, Gerber inputs as bitmap outputs) to drop-on-demand the embossed pattern on a surface. ) Provides a method of printing.

In various inorganic or organic based microelectronics, optoelectronic devices and circuit manufacturing applications, there is a need to pattern one or more materials, including the devices or circuits to be manufactured. The pattern formed for one of several reasons may be as follows.

* Etching masks (for wet, dry, electrochemical, etc.)

Selective Area Deposition Masks (Lift-Off, Air-Bridge [2-Level Process], Electroplating, Electrophoresis, etc.)

* Containment wells (for phosphors, liquid crystals, light emitting polymers, etc.)

* Dielectric micro-via composition multilevel metal interconnect

Network of metal conductor cross-over resistor-capacitor nodes                 

* Two-dimensional and three-dimensional membranes (static or removable)

* Spacer between part levels (provides controlled gap dimensions between parts)

* Reflow thermosetting adhesives for partial parts (limited glue bonding partial parts)

The patterned shapes as above can be removed or left in place after providing the required functionality.

The most popular method for providing surface relief structures is photolit hography. This requires the use of a photosensitive material applied to the surface as a whole coating (spin-casting or dipping) or as a whole area sheet (thin layer). In front of the coated wafer, the material is applied in a light controlled laboratory so that the photosensitive material is not previously exposed prior to introducing the required pattern mask. The pattern mask can be one of a contact mask, a proximity mask, or a projection mask. In all cases, the mask must be manufactured as a discrete device for high precision and carefully protected against damage or dust / dust. When the mask is placed in position, a radiation lamp that is compatible with the photoinitiator used for the photosensitive material can expose the coated substrate to areas that are not protected by the mask. Depending on the type of photosensitive material used, the pattern transition can be positive or negative with respect to the mask. After photosensitivity, the photosensitive material should be exposed to developing chemicals that modify the chemical properties of the coating to allow the untreated material to be cleaned with a water based deep bath or conveyor shower / spray.                 

Although spin cast, dip, or sheet thin layer photolithography that produces a surface relief pattern is successful, we have the following problems.

* Material waste (because of the whole area technology)

* Selected area 3D pattern is very difficult and time consuming.

* The chemical properties used for photosensitive materials are very toxic.

* Wide volume reusability of toxic and developing chemicals

Simple patterns also have the following multi-step process:

           Photoresist coating;

           Mask alignment;

           Radiation exposure;

           Mask removal;

           Pattern phenomenon;

           Washing away excess material; And

           Substrate drying.

As another process capable of providing a patterned relief structure on a surface, including stencils (screen printing), microdot conversion (stamping), laser write etching (including erosion scrubbing and direct write photolithography equivalent imaging). We can solve one or more of these problems. Each technique has the advantages and limitations induced by the item of intended application, the so-called

* Rate of pattern generation                 

* Embossed pattern thickness

* Controlled etching ability

The cost of the process

* Ease of process use

Not all of the above problems can be solved by any one process.

Preferred embodiments of the present invention seek to solve these and other problems.

In one aspect, the present invention provides a method of forming a masking pattern on a surface. The method includes depositing a plurality of droplets on a surface to form a masking pattern using a droplet deposition apparatus; And controlling the local environment of the working area to control the formation of a masking pattern on the surface, wherein the droplet passes through the working area between the deposition apparatus and the surface.

As described in more detail below, it has been found that the control of the local environment only in the working area has an important effect on the formation of a masking pattern on the surface. Preferably, the formation of the masking pattern is controlled to have a predetermined structural characteristic.

A preferred technique is drop-on-demand printing, which allows individual droplets, or continuous droplet flow, to be deposited on the surface to form a masking pattern. Examples of drop-on-demand printing methods include ink jet methods based on piezoelectric, piezoresistive, relaxer and bubble jet induced pressure generation that eject droplets from the printhead.                 

Depending on the purpose of the masking pattern, the masking pattern may be formed of various materials. For example, the pattern may be formed of at least one of alkyd resin, acrylic resin, phenol resin, rubber chloride, epoxy, polyester, polyurethane, polyvinyl, silicone, fluorocarbon, polyimide, polyamide, and polystyrene. The pattern may be formed of one of metal, dielectric, magnetic, light emitting, absorbing, light transmitting, conductive, insulating, semiconductor or superconducting material. The deposition material will be a 100% solid polymer.

The deposition material may be an organically changed ceramic.

The deposition material may be in solution or in solution gelled form. The solvent may be one of water, low alcohol, ethylene glycol, acetone, hexane, benzene, chlorobenzene, toluene, paraxylene and methylene chloride.

Preferably, the action zone extends from the deposition apparatus to the surface. However, the working area can only partially extend between the deposition apparatus and the surface.

In a preferred embodiment, relative movement occurs between the deposition apparatus and the surface such that the action zone moves across the surface during the formation of a masking pattern.

Preferably, the local environment of the working area is controlled for at least one or more of the following reasons.

(Iii) controlling the adhesion of droplets on the surface;

(Ii) controlling the diffusion of droplets on the surface;

(Iii) control the placement of droplets on the surface; And

(Iii) avoid the confinement of the drops;                 

Preferably, the local temperature of the working zone is controlled to control the rate of solidification of the droplets on the surface.

Preferably, local air in the action zone is controlled. Such localized air control can be opposed to air control associated with the entire area to be printed, thereby providing an inexpensive means of controlling the required deposition properties. In one embodiment, this area can be obtained by enclosing the printhead with a confinement surface, such as, for example, a bellows-like structure that provides a constant pressure of air or a specific inert or reactive gas injection (gas may be heated or Is cooled). The weak vacuum can be supported in the bellows using a dry vacuum pumping arrangement.

Thus, in one preferred configuration, at least a partial vacuum is generated in the working area to substantially avoid contamination of the droplets while passing from the deposition apparatus to the surface. An air pressure difference extending between the deposition apparatus and the surface may occur in the working area. Alternatively, or in addition, an inert or reactive gas can be inserted into the action zone during droplet deposition.

In a preferred embodiment, the working area is locally exposed to electromagnetic radiation to control the coalescence of droplets on the surface, thereby controlling the solidification of the masking pattern. The duration of local exposure of the area acting on electromagnetic radiation can be controlled to control the diffusion of droplets on the surface, thereby controlling the resulting shape of the masking pattern. Alternatively, or additionally, the intensity of electromagnetic radiation is controlled to control the diffusion of droplets on the surface, thereby controlling the conclusive shape of the masking pattern.                 

Drops of deposition material may be radiation cured before and / or after deposition on the surface. In one embodiment, the radiation cure has a dresshold energy greater than or equal to 1 mJ.cm ^-2 .

For example, the line width and profile control of the masking pattern can be achieved by controlling the time after impact that the deposited material is exposed to radiation curing. The time period is preferably 1 to 2000 ms, more preferably 50 to 300 ms.

Exposure of critical radiation promotes a change in liquid mass rheology, thereby affecting the rate of diffusion of droplets on the surface and the degree of adhesion to adjacent droplets. Such control of droplet adhesion and curing can enable a masking pattern with straight edges, equilibrium sides to be formed in the time domain of 0 to 100 ms after droplet deposition. Computational fluid dynamics (CFD) modeling has provided traces of impact dynamics and surface wet reactions of droplets in the time domain up to and during coalescence. Drop volume, diameter and impact energy (impact interval), combined with droplet injection time, have been found to contribute directly to the coalescence reaction.

The nature of the use of the masking pattern is indicative of the drop spray rate and the surface transfer rate leading to the center-to-center spacing of the drops. Adjustment of the operating parameter may allow direct control of the drop-to-drop time domain.

In order to achieve the linear dynamic range, the wetness of the surface and the solidification rate of the droplets on the surface are preferably controlled. This can be accomplished by controlling the surface energy of the surface and the properties of the material used in the deposition process. Surface energy control can be affected in many ways, including erosion, polishing, ozone treatment, plasma exposure, and coating of non-wetting materials. Fluid coagulation control can be achieved by the chemical design of the fluid and the type, extent and timing of radiation curing.

Radiation curing can be provided by any suitable means.

In order to provide the ability to select a time and location relative to the droplet impact area when radiation interacts with the deposited terrain, the light output from the radiation source can be delivered to the printhead using a fiber optic light guide configuration. . Multiple fiber optic light guide tubes may be used that belong to or are coupled with the device providing the line output conversion.

Electromagnetic radiation may be one of ultraviolet light, visible light, infrared light, microwaves and alpha particles. In order to achieve high speed curing, it is desirable that the irradiation of the photoinitiator of the deposited material and the radiation source to cure the controlled material be controlled with the exposure time of the radiation. Radiation curing may be provided with multiple wavelengths of radiation incident sequentially or parallel to the deposited droplets.

The radiation source may comprise at least one light emitting diode (LED). The or each LED may be inorganic or organic and may be based on SiC, InGaN or PPV derivatives. The radiation source may include a series of discrete LEDs. Such sources may include a number of discrete LEDs that are butted together to form an independently addressable linear or area array of LEDs. Plastic encapsulation packaging can be removed to reduce the volume of the array to facilitate integration close to the deposition printhead.                 

Alternatively, the radiation source may comprise at least one semiconductor quantum well solid state laser. That or each laser may be inorganic or organic and may be based on SiC, InGaN or PPV derivatives. The radiation source may comprise a series of separate lasers. Such a source may comprise an array of independently addressable semiconductor quantum well stack solid state lasers. The laser can be fabricated on a single quartz wafer. The wafer can be diced to generate a line of laser that can be directly coupled to the printhead or the angular rotatable housing to facilitate curing in flight, impact, and diffusion past the surface. Alternatively, the laser can be made from a flexible plastic sheet.

The radiation source may comprise at least one light emitting polymer (LEP), which may be used in striplights or full area lighting devices. The LEP may be a thin film device. Radiation curing can be accomplished as a full area process by using thin film inorganic or organic luminescent materials. Thin film device designs define the wavelength band to be emitted by the device. The emission can be adjusted to suit a particular wavelength or wavelengths. Discrete patterns or bands of wavelengths can be achieved in device manufacturing. Pattern or band focusing or defocusing can be made in a convex lens configuration. Convex lenses can be deposited using drop-on-demand technology. In one preferred embodiment, the LEP emits filtered white light to select wavelengths for curing or illumination of the deposited masking pattern.

The present invention can provide a highly efficient etch mask printing system by using a reel-to-reel and / or robot substrate transfer method. For example, multiple sets of printheads can be used to allow the multiplicity of separate workstations to be operated along the open length of the plastic sheet held between two tensioned "feed" and "receive" drums.

Preferably, a standard alignment mark is generated. A series of codings can be deposited on individual substrates (eg for printed circuit boards for wet etching). This can be accomplished by using a drop-on-demand printing method using color or transparent ink.

The present invention can utilize dynamic imaging of deposited masking patterns. Such imaging can be provided as a linear imaging device integrated directly into the printhead. Real-time imaging can be accomplished by integrating an imaging array such as a charge coupled device (CCD) on both sides of the printhead assembly, thereby allowing bidirectional print imaging. Real-time imaging can be accomplished using inorganic imaging devices such as CCDs or silicon x-y addressable photodiode arrays or as (photodiodes) of thin film organic photoconductive pixel arrays.

In order to increase processing yield, software for pattern recognition and overlay comparison based can be used, for example, using a wide area organic photoconductive array. This may enable finished substrates to be imaged at one time without the aid of expensive lens construction. The organic photodiode region array preferably has pixel resolution that is compatible with the best shape to be imaged. The image is preferably a 1: 1 correspondence that makes software based pattern recognition easier and faster.                 

The present invention preferably uses a bimorph or other electrically driven electromagnetic radiation shutter that selectively covers the nozzle holes of the printhead. The shutter assembly is a micromachined structure. The shutter includes means for cleaning the nozzle surface. Accordingly, in another aspect, the present invention provides a droplet deposition apparatus comprising a nozzle shutter comprising means for selectively covering a deposition chamber, a nozzle fluidly connected to the deposition chamber and a nozzle groove, and for cleaning the surface of the nozzle. .

In one preferred embodiment, the cleaning means comprises a series of thin film / thick film wiper blades for cleaning the nozzle surface. The apparatus may include a series of fluid ducts that assist in the flow of residual ink in the reservoir, at the wiper blades located at both ends of the shutter assembly. A vacuum suction tube is placed in the reservoir to periodically empty the stored fluid / ink.

The in situ environment and radiation shutter assembly may act as a real time pulsed plasma electrode and / or printhead vacuum detonator providing surface pretreatment in close proximity to the drop landing area.

The surface of the wiper blades can be locally hardened to provide improved cleaning action and resistance. The blade is preferably cured by exposing the surface of the shutter to a beam of high energy ions (ion implantation or plasma implantation).

The method may utilize multiple droplet spraying wavelengths and sequences, providing variable speed radiation cured printing. Specific drive waveform sequences may be used depending on the type of masking pattern.                 

Surface pretreatment can be performed, for example, and / or prior to the deposition of the masking pattern. Surface pretreatment may be carried out by local ozone, radiation exposure, spray head or ink jet printhead, or acid or alkali sprayed from the spray head, or solvent from the ink jet printhead.

Real time height adjustment of the ink jet printhead can be performed during deposition of the masking layer. This positioning can be done using a bimorph or cantilevered or servo drive positioning transducer that causes the printhead to move on the z axis. The height adjustment is preferably at 50 to 2000 μm, more preferably at 0.75 to 1.25 mm. Positioning transducers may be located at both ends of the printhead such that the printhead is disposed in equilibrium. Such real-time positioning may be the result of electro-optical (laser [range finder principle] or LED combined with phototransistor or photovoltaic pair) or capacitive or inductive sensing element. Such height control can facilitate direct fluid contact transfer.

The present invention can enable wide format printing by utilizing a printhead enclosure that can accommodate multiple printheads. For example, a series of printheads can be butted with a common nozzle format. This can keep the pattern with the conclusive equilateral aspect unaffected even if the number of nozzles is increased. Butting errors compromise such prints, and therefore need to incorporate a common nozzle plate. By utilizing the piezoelectric positioning of the He-Ne sighting laser assembly, which can be removed once the alignment is complete, the butted printhead can be aligned on the x-y-z axis.                 

In order to optimize the mask pattern line width, the formation of the deposition material can be controlled. The properties of the deposited material, such as the glass transition temperature T _g , can affect the hardness and temperature stability of the deposited material. Changes in the volume-to-surface photoinitiator ratio can affect the cure rate. Optimal behavior occurs at 1 to 4: 1 (surface: volume).

Proximity bonding, low temperature, microwave initiating gas emission radiation sources can promote wide area polymer cross linking. The low surface irradiates the mask material by making a surface relief pattern therein that allows emission induced photo species to couple out at the substrate surface. The surface relief needed to extract the plasma discharge photons of the desired wavelength (gas characteristics) can be a diffused structure, such as a diffuser, dot matrix, or MOS-Eye lens matrix. Preferred embodiments use convex lens type arrays, where a substantially rectangular cross section (less than or equal to 90 ^° ) projection width, height and wall slope affect the efficiency of the coupling for a given wavelength of light.

The designated nozzle plate geometry can affect the placement control of droplets ejected from the nozzle array. If a shearing action (ie, Xaar XJ series printhead) is used, the nozzle stagger is preferably defined at the nozzle plate for straight character printing. It is necessary to vary the drop spacing by operating outside of the printhead in the standard parameter range to obtain droplet adhesion that creates well defined lines.

The masking pattern may be an electrode surface solder reflow resistance mask pattern. In this example, the method of forming the solder mask is similar to the method of forming the etch mask described above, and the choice of ink formation should reflect the high temperatures applied in the solder dip coating and thermal wave solder reflow processes. Soluble materials that can be used as the solder mask include silicone, polyimide, PTFE and epoxy.

The masking pattern may be a 3D etch mask. Many device fabrication applications require the production of variable build heights or etch depth shapes. A droplet deposition process can be used to define such shapes using one of multiple passages of a pattern where the multiple drops solidified or deposited patterns in a particular area are different at different times.

In one preferred embodiment, the masking pattern is a dry etch resistance, inorganic etch mask. Etch masks may be formed based on inorganic or mixed organic-inorganic fluid systems. In such cases, chemical stability is applied to the properties of the fluid and to the printhead material and the nozzle non-wet coating. Organic-inorganic fluids (Omercer-organically modified ceramics, sol-gels, metal-organic, etc.) can use radiation curing such as UV. The masking pattern may be an electroless or electroplating bath resistor, an etching mask pattern. The printing method is the same as for the printed wiring board etch mask pattern. The difference lies in the choice of materials used and the need to construct a mask pattern that is three-dimensional in nature. Typical materials include epoxy, polycarbonite, silicone, PTFE, polychlorotrifluoroethylene, polyimide, polyisoprene, polypropylenepolystyrene, and the like.

The masking pattern may be an additional plating etch mask.

The masking pattern may be a high resolution etch mask. High resolution has different measurements depending on the application provided. For the purposes of this disclosure, high resolution means shape size smaller than 10 μm.

The masking pattern may be an electrically conductive masking layer. Such masking layer may be left in place after use, such as in the seed layer, for the electroless / electrolytic coating of the electrode pattern. The masking layer can be carbon based or metal acetate based (ie, palladium) to effect certain conductive and chemical interfacial reactions prior to coating with the selective metal.

The masking pattern may be a decorative surface etch mask. The decorative surface may be based on the properties of the ink used to form the surface relief pattern. Such a system can be used as a safety device due to the unique nature of particulate dispersion in solids that can be imaged and recorded as safety signals.

The present invention can use a UV (or other energy / radiation) line source of deposition of an etch mask pattern. Such a line source can provide a uniform area of radiation (UV-visible-IR-electron) exposure beyond the width of the selected printhead. The line source structure in one preferred embodiment uses fanned fiber bundles to provide a single line of fibers of individual diameters of 0.25 to 1 mm. The fiber lines are in direct contact and adhere to the polyimide sheet support material, which provides some stiffness and ease of handling.

The present invention also provides a method of forming a circuit pattern on a circuit board using droplet injection techniques to deposit droplets of deposition material, the method on the circuit board to at least partially fill via holes formed in the circuit board. Depositing a plurality of droplets on the substrate. Such a method can be carried out in two different ways: coated via hole in-fill or surface tension inducing coating.

The in-fill process uses the multiplicity of droplets to generate droplets to fill holes under capillary action. UV curing solidifies the droplets deposited to form a solid plug.

Surface tension induction coating processes require a drop size larger than the hole size to be filled.

Preferably, the method comprises the step of at least partially removing the masking pattern. The removal process can be dry or wet. The dry process involves a variety of gases including argon, oxygen, argon-oxygen mixtures, CF ₄ -oxygen mixtures, argon-water vapors, etc. (inert gas rare earth oxide series; reactive gases are treated with hydrogen, oxygen, chlorine, fluorine, etc.). Use plasma based chemicals. Wet processes use both aqueous and non-aqueous solvent systems. The aqueous based chemical caustic is mainly caustic based (a typical process is injected past a roller feed of 5% NaOH of H ₂ O at 30 ° C.). The non-aqueous solvent to remove the mask of acrylic acid is:

* Chloroform (Solubility)

* Dichloromethane (expansion and dissolution-remove quickly)

Tetrachloromethane (dissolution)

* Chlorobenzene (expansion)

* 1,1,2-trichloromethane (soluble)                 

N-methylphylolodinone [NMP] (expansion-slow process)

It includes.

The method may utilize a dual printhead configuration as a common integrated copy curing source. This configuration may have a copy source located at the outer edge and center of the dual back-to-back printhead configuration. This allows the printhead to print in a bi-directional mode, which provides the same degree of radiation exposure regardless of the front or back print.

Masking patterns can be formed based on chemical attachment transfer. Chemical attachment can be via chiral or hydrophilic reactions on the catalyzed surface.

The present invention can be utilized to form a single panel printed wiring board (PWB) back-to-print auto registration etch mask printing process. This process may use, for example, two facing printheads or a butted linear array of printheads, aligned in relation to each other using a He-Ne laser beam and a silicon diode photodetector.

The masking pattern may be a mask pattern with a near vertical wall. Calculation of droplets to be ejected by ink jet printheads by interacting with solid surfaces Fluid dynamic modeling (based on FlowScien ce's Flow 3D modeling software) proposed the ability to create single dots with sidewalls very close to vertical. The drop spacing and solidification state of the previous drop, combined with the drop's impact rate and ink viscosity, affect the adhesion rate to form a line. In order for the line to have a vertical sidewall profile, it is necessary for the coalescence process to occur within the time it takes for the droplet material to diffuse to the width of the solidified droplet (ie, less than or equal to 10 ms).

The masking pattern may be an ion implantation mask. The purpose of such masking material is to protect the surface under a mask from a high energy ion beam. The energy range is 10 eV to 50 MeV. The thickness of the masking layer will depend on the energy of the irradiation beam. For high energy, the expected mask thickness will be less than or equal to 10 μm.

The masking pattern may be a confinement well mask, such as used in the manufacture of single or multicolor light emitting polymer displays (see FIG. 26). Other display devices using such confinement wells include inorganic lanthanide element dyes or organic small molecule dye structures.

The present invention also provides a method of forming a spacer pattern on a surface, the method comprising:

Depositing a plurality of droplets on a surface to form a spacer pattern using a droplet deposition apparatus; And

During droplet deposition, controlling the local environment of the working area to control the formation of a spacer pattern on the surface, the droplets passing through the working area located between the deposition apparatus and the surface.

Stand-off spacers are typically used to separate two parts of a flat panel display device. One example is the use of known conductive and secondary electron emissive spacer materials used in vacuum based field emission displays. Another example is a separate well structure used in liquid crystal displays. Well structures include liquid crystals that can be ink jet printed or vacuum injected to fill the wells.

The present invention also extends to methods of forming masking patterns using all dry, charged toner, and light transfer processes. Accordingly, the present invention also provides a method of forming an embossed pattern on a surface, the method comprising:

Selectively irradiating a charged roller to selectively remove electric charge at a portion of the roller;

Depositing a plurality of droplets passing through an action zone located between the deposition apparatus and the roller on the charged portion of the roller using the droplet deposition apparatus;

During droplet deposition, controlling the local environment of the working area to control the structure of the pattern formed on the roller; And

Conveying the deposited material onto the surface in the roller to form an embossed pattern on the surface.

This toner is the application of photocopying, which is a nano / microcapsule / particulates / drop system which provides the necessary diameter and material properties for charge accumulation on the toner and particle transitions to the photoconductor and substrate to be patterned. Another process uses toners that can be processed using in situ high speed thermal / infrared (pulse or continuous irradiation) processing means to reflow microcapsules / particles / droplets to coalesce materials. For example, the toner microcapsules / particles are considered to be actually solid drops of low temperature (<200 ° C.) thermoplastics. Charged particles that dissolve as temperature are introduced. The degree of melting is sufficient to allow coalescence without excessive surface wet (reflow). The removal of heat allows the thermoplastic to solidify again, forming the required etch mask pattern. It is contemplated that hollow capsules will be used to contain certain materials (ie, polymers, inorganics, etc.).

Preferred features of the present invention will be described by way of example only with reference to the accompanying drawings.

1 is a captured image from an animation sequence obtained from a computational fluid dynamic model of the diffusion reaction of a typical masking ink on the same surface where the surface energy is observed in a typical printed wiring board material. Drop spacing before exposure to the dress radiation radiation, surface energy interactions, and line width and edge quality at which time was achieved.

FIG. 2 [a-b] is an image captured from an animation sequence obtained from a computational fluid dynamic model of the interaction of two ink jet droplets in a 2D vertical plane covering a time interval from impact out to 1 ms.

3 is a captured image from an animation sequence obtained from a computational fluid dynamic model of the interaction of two ink jet droplets of a 2D horizontal plane covering a time interval from impact out to 1 ms.

4 is a layout of a preferred printing system showing substrate transfer with respect to the printhead.

Fig. 5A-B shows the relationship between the radiation line source and the printhead.

6 is a captured image from an animation sequence obtained from a computational fluid dynamic model of the interaction of two ink jet droplets of 3D covering a time interval of up to 250 ms at impact out.

7 illustrates the relationship between a semiconductor laser or light emitting diode (LED) array, an addressable radiation source, and a printhead.

8 illustrates a semiconductor laser array integrated on a printhead.

9 illustrates a high efficiency production system based on reel-to-reel flexible substrate transfer.

10 illustrates a light emitting polymer radiation source exhibiting ink cure close to the printhead.

11 illustrates a linear addressable array imaging device (organic photoconductor array, etc.) integrated directly on a print head.

12 illustrates a full area imaging system based on an organic photoconductive array.

13 shows a radiation shutter and nozzle plate cleaning device integrated directly on a printhead. Represents a three action wiper blade to clean the nozzle plate in real time.

14 shows the ion implantation surface of the triple action wiper blade for improved tip stiffness and longevity.

15 illustrates a bimorph transducer designed to provide real time printhead height adjustment.                 

FIG. 16 illustrates a localized environmental control bellows structure related to local areas only in the printhead. FIG.

FIG. 17 shows full area microwave induced gas emission emitting radiation to photoinitiators used in inks printed on a single plane in wavelength characteristics.

18-20 relate to the production of a radiation line source integrated on a printhead, providing transfer of radiation to a drop impact area and an area associated with a distance equal to time after an impact of 100 microseconds.

Fig. 21 is a view showing a printed wiring board hole tenting method.

FIG. 22 illustrates a common radiation curing system integrated into a dual printhead configuration.

FIG. 23 illustrates chemically adhered printing using ink jet printheads. FIG.

FIG. 24 illustrates a dual printhead configuration allowing back-to-front printing in parallel with high pattern-to-pattern alignment.

25 shows a drop-on-demand printed ion implantation patterning mask.

FIG. 26 illustrates a microvia hole and containment well pattern mask. FIG.

27 shows a drop-on-demand printed stand-off spacer.

Preferred embodiments of the present invention use, but are not limited to, the XaarJet ^™ XJ500 printhead. This print head has a resolution of 180 dpi and an injection frequency of 4 kHz. Each nozzle that sprays a drop of approximately 51 μm in diameter and a volume of 70 pL with a 83 kPa injection cycle delay has a diameter of 50 μm. The geometry of the nozzles associated with the 500 nozzles, nozzle plate, has a twist of 23.5 μm in a row (on-demand nozzle plate device).

The printhead is mounted on the printing system to allow y-axis movement (motor controlled by software) to print a single piece of text / image data. The printhead can also be moved on the z axis (motor controlled by software) for height adjustment of 0.1 to 10 mm. The substrate is printed moving in the + ve or -ve x axis at a speed of 70 to 504 mm / s, preferably 280 mm / s. The drive shaft encoder associated with the substrate movement has a resolution of 5 μm with 14 associated print engine encoder splitting elements. Alternatively, a linear encoder with a resolution of 1 μm or less can be used to make an improved address. The resulting drop spacing on the axis perpendicular to the printhead is 40 to 90 μm, preferably 70 μm, to match the image resolution.

Current processes involving 70 μm steps (or due to the use of two printheads or using Xaar XJ1000 printheads, or similar devices) use two paths per quantity to double nozzle resolution.

Since the image resolution can be high (dpi) and the appropriate addressability on the substrate can also be high, the use of equivalent encoder signals is required.

The ink used in the Xaar frit head is UV cured, and cyan (no matter what color or bright ink can be specified) has a concentration close to 1, viscosity of 9 to 30 mPa · s and surface tension of 22 to 32 mN / m. Have This ink requires an irradiation energy density of 1 to 2 J / cm ² to reach a fully cured state. Droplets are ejected from the nozzle using pressure pulses as a result of the cutting initiated by the electric field of the piezoelectric ceramic. The droplet has an impact speed of approximately 6 m / s.

Drops of UV curable ink are subjected to inertia damping and surface diffusion before they solidify by the action of UV wavelength light that is exposed to the ink impinging on the surface and causing chemical crosslinking. UV curing takes place in two parts, the first locally at the printhead and the second at full area hardcore process. Local curing (see FIG. 1) is used to obtain a controlled degree of chemical crosslinking or curing sufficient to control the diffusion distance to limit the size of the place to be printed. If such exposure occurs, the degree, time and duration of the UV exposure is controlled to allow the droplet adhesion required to make a continuous line in any arrangement. In one embodiment, a UVP spotcure source (SCL1-6) using a 400 WHg lamp (UV band A) is used. The UV source has six outputs that are optically imaged at the ends of the fiber bundles filled with six liquids. Each glass light path is F.S.I. Connected to a spot-to-line converter. The transducer is based on a randomized bundle of fiber that extends to a specific arrangement and polished end. Since the fiber portion is a direct match mapping, randomization allows for an overall uniformity of light output (constant illumination). The line converters that allow coin hardening across the entire printhead width have an irradiation output area of 75 mm x 4.6 mm.

The time delay between droplet impact and the first exposure to localized UV radiation reaches up to 1000 ms. This line converter fiber optic system can vary in height (z axis relative to the substrate surface) to make the onset of UV irradiation a delay time of 15 to 20 microseconds (see FIG. 2). This element is adjusted to allow for optimal coalescence of individual drops in all directions (vertical axis, curve, 45 ^° bend) to achieve the best overall line edge straightness, cross-sectional profile and robustness.

Final full area curing is achieved using a Fusion UV F300S curing system. This system uses 300W per linear inch (total output 1800W) D-bulb spectral emission (see FIG. 3) to provide full cure of the ink at the optimal print speed.

The copper printed wiring boards used in the preferred embodiment were pretreated using Scotch Bright pads followed by IPA cleaning, oiled with IPA. This pretreatment not only introduces a roughness to the surface to increase the adhesion of the ink jet printed, etch mask pattern, but also facilitates copper oxide suppression, chromate coating removal. Other pretreatments are also possible, including electroless cleaning (persulfate microetching followed by nitrate chromate removal) or anti-Taninish treatment, which provides a cleaning surface where the adhesion promoter film / agent may be placed. Such a process is compatible with the scope of the art methods. The resulting ink jet printed etch mask pattern is attached to a wide copper finish and other surfaces, including stainless steel, aluminum, plastic, nickel electrodes on ceramic, ceramics, tetrahedral carbon, diamond-like carbon, and glass. The solidified ink must be chemically resistant and physically attached to the substrate against a wide range of copper corrosion solutions, including those based on copper containing chloride, ammonia and alkali composition ratios.

After etching, the mask pattern must be removed. This can be accomplished in a variety of ways, including wet (solvent containing caustic solution, dichloromethane, NMP, etc.) and dry (reactive ion and inert plasma) processes.

Next-generation mask printing will be as small as XaarJet ^™ XJ100 (360 dpi) or grayscale, with a 21 pL droplet size of 36.2 μm in diameter. The relevant drop interval will be 25 to 40 μm and the torsion of the nozzle row and the printhead firing cycle delay will be optimized to suit the printhead firing frequency. The resulting etch mask pattern will appear smooth as a result of small droplet filled edges (curve steps, etc.) associated with grayscale operation. Using this arrangement, the target line width is 50 to 100 μm. Other system upgrades will provide high resolution printing that requires more precise dot placement (ie linearly coded xy movements less than or equal to 1 μm precision and repeatability).

Referring to Figure 1, the image graphically shows the diffusion of a drop of ink. Important shapes are the symmetry of diffusion on the surface that is isotropic everywhere (as elements of the model) and the diffusion rate (at room temperature).

The ink used in this simulation was a 100% solid polymer with a viscosity of 10 to 30 mPa · s and a surface tension of 24 to 30 mPa / m. The substrate surface is defined as having a wetting ^angle of 22 ^{o with} the ink.

It should be evident from such images that the location of the continuous droplet placement relative to the diffusion rate will affect the droplet adhesion required to create the continuous pattern. Moreover, if the ink droplets are not controlled for surface compensation and expansion, there will be an unbalanced edge line.

The inventor has realized the importance of defining a certain time range in which such control must be practiced and the method used to achieve it. Computational fluid dynamics (CFD) modeling began to learn fluid responses, supported by high-speed imaging of droplet responses. An important treatment requirement is to provide droplet coalescence and hardening to provide a line with straight edges, equilibrium sides.

A feature of importance is the ability to control the lateral movement of the print head to select side-by-side droplet placement, such as dot resolution (depending on the size of the sprayed liquid droplets and actually impacting the substrate surface). The properties of where to be printed represent the edge limitations that can be achieved with a particular printhead in relation to the drop diameter. The shape to be achieved can be made to be of good quality using the micropotato grayscale level, in which individual drops can be accessed / controlled in software. The importance of this shape is in the response of the electrical circuit defined by the mask pattern. The connecting conductor elements of the circuit are expected to have a balanced, smooth edge, straight or curved shape, ideally processing without the roughness of the edges. Edge roughness can provide signal degradation due to unnecessary scattering. As a function of the printing mode, a detailed understanding of droplet placement accuracy and print speed, liquid droplet impact and interaction with the substrate surface, and the multiplicity of masking material drying / curing are very important.

Of particular importance to the present invention is the limitation of the operating parameter space for liquid droplets, regardless of the print engine or print mode of operation used below.

Ink viscosity for 100% solids (5 to 50 mPa.s)

* Surface tension ≤40 mN / m

Drop impact speed ≤10 m / s

* Droplet diameter ≤50㎛

2 [a-b] and 3 show two drops of inertial dynamics and subsequent diffusion reactions delayed for an impact time of 250 μs (equivalent to 70 μm center-to-center spacing of droplets). The smallest for a particular ink (viscosity, surface tension, impact velocity, droplet volume, etc.) on a given surface (surface roughness, surface energy, chemical stability with ink, etc.) printed in a specific environment (humidity, temperature, dust concentration, etc.) In order to achieve the size, the rheology of the ink should be emphasized that the movement (surface diffusion) is bound in the time range of 970 ms. If diffusion continues before solidification, the printed line will increase line width until the diffusion action is constrained by a balance between surface capillary force and ink surface tension.

Changes in ink, printhead, substrate material, and printing environment will affect the time period, which is the correct adhesion of successive droplets required to print the image of interest. Wet droplets adhering to the solid ink dot (wet with a non-wet reaction to be considered here) may have different time periods for shapes with straighter edge equilibrium sides than those described above for the wet droplets adhering to the wet droplets described above. Will have Such changes in shape do not depart from the scope of the present invention. In order to achieve such control, it is not possible to use a solidification process that is not integrated with the print head.

The present invention provides the ability to select a time and location relative to the drop impact area when light irradiation interacts with the liquid ink where it is printed.

Drop-on-demand ink jet print heads eject a single drop (or series of drops) of a particular ink formation that solidifies at impact or at the correct time thereafter, with droplet diffusion and surface moment and surface capillary phenomena.

0 to 15 Hz-Change less than 90 ° at the contact angle with the surface greater than 130 °.

This is an area for controlling the cross-sectional profile of individual dots.

15 to 250 kPa-impact of fully braked inertia

250 to 1000 mW-the coalescence of the droplets has an equilibrium surface that causes printing of straight lines.

1000 kPa or more-Ink rheology coupled to the difference in surface energy and ink surface tension provides energy to promote continuous diffusion until the ink is irradiated to the crosslinked UV cured polymer.

In a preferred embodiment of the present invention, ink formation cures at high speed when exposed to electromagnetic radiation. Preferably, the electromagnetic radiation comprises wavelength bands assigned to ultraviolet light (including deep UV and UVA, UVB, UVC), visible light, and infrared (including far-away infrared light), microwaves and α-particles (alpha). do.                 

4 shows the geometric arrangement of one embodiment of an ink jet printing masking system. In particular, the figure shows the substrate path on the x-axis (print direction-positive or negative, ie bidirectional printing integrated with light sources on both sides of the printhead) at a rate depending on the jet frequency and drop size of the printhead used. y-axis printing can be by a step-and-refit amount or linear combination of multiple printheads to provide compensation to the nozzle beyond the y-axis diameter of interest (board length, etc.).

5 shows the geometric relationship between the printhead and the integrated light source, showing particular emphasis on the position and width of the irradiated area. Also shown are the z-axis height adjustments that can be controlled beyond the intensity investigated. For example, it is possible to consider a typical printing movement based on the use of a Xa ar XJ500 ^™ printhead that sprays a UV cured polymer ink. A typical process (see the above-described background information) 280㎜ / s x-axis of the substrate ^{70 pL (70 × 10 -12 ℓ} ) injected at a rate of yidongyul and 4㎑ 51㎛ volume and size of the drops and about 1 to 200 mJ / Localized ink dot stitching radiant energy of cm ² is used. This provides a drop impact center-to-center spacing of 70 μm (see FIG. 6) for printhead heights higher than substrates of 0.1 to 2 mm (most preferably 0.5 mm). The resulting dot pattern is allowed to diffuse on the surface for between 80 and 100 microseconds before being exposed to the integrated UV line source (area of y axis 70 mm, x axis 4.5 mm). The resulting masking material line has a width of 140 μm. Compensation due to errors related to drop firing angle, drop velocity, substrate speed, and spray timing were ignored in this example.

The method of irradiating a drop-on-demand impact drop should not be solely due to a lamp or fiber optic light guide tube based system. 7 and 8 show a preferred embodiment, wherein the electromagnetic radiation means is an array of independently addressable semiconductor solid state lasers or light emitting diodes (LED-organic or inorganic). In such an embodiment, the solid state semiconductor laser irradiates flying fluid droplets so that the droplets impinge on the substrate surface and are present / diffusing, thereby providing surface moisture (and robust dot / line cross section, especially for 100% solid polymers) and interfacial impact effects. Influence fluid characteristics on the surface and in flight to limit To test whether this concept is technically feasible, it is necessary to consider some basic features. The expected drop velocity will be 1 to 3 m / s. For purposes of illustration, a drawing of 3 m / s will be used. Assume the printhead-to-board distance is 2 mm. In addition, it is assumed that the drop diameter is 50 μm and the print speed (substrate movement relative to the printhead) is 0.5 m / s at a drop ejection rate of 1 kPa. The calculated travel time allowing angular derivation of the drop flight path is 1.37 ms.

There will be a mechanical blind spot right in front of the nozzle shutter assembly where the laser light beam cannot access the sprayed droplets. Because of the blind spot depth of 0.6 mm, the available irradiation time, obtained from the rest of the drop flight, will be 1.16 ms. Assuming 100 mW / cm 2 laser beam intensity and simple linear absorption, the level of exposure would be 116 μJ / cm 2.

Irradiation of the drops will not be uniform throughout the flight time. This is due in part to the absorption performance (light exposure photoinitiator loss profile) of the fluid drop and partly due to the homogeneity of the crosslinks (concentration and distribution of the photoinitiator) in the volume of the surface and the fluid drop. In this regard, one is necessary to understand the irradiation intensity (mm / cm 2) and the exposure amount (mJ / cm 2).

The rate of photochemical action depends firstly on the probability of incident photons absorbed by the molecules of the selected photoinitiator and secondly on the concentration of photoinitiator used. The purpose of initial in-flight and surface exposure is to promote sufficient crosslinking to limit or confine the diffusion action of the impacting droplet. This needs to absorb the droplet kinetic energy while influencing proper adhesion of the cured droplets on the substrate surface. If the laser beam profile is configured to be a "best" design and the luminosity is greater than the critical dresshold, there is a possibility to consider a static irradiation process that covers the entire accessible flight path of the droplet. A second laser source, exhibiting a "best" beam profile, continuously irradiates the substrate surface just before the drop hits. The laser source of balanced beam irradiation with structural interference occurs at the drop impact point. The actual interference area is the ellipse of the smallest axis (65 μm) 25% larger than the droplet diameter. The exposure time for the second laser is shown as the "best" arrangement and substrate transfer speed used (for 1 mm beamline width). The total exposure time is 2 ms. If the "best" beam had an intensity of 100 mW / cm 2, the level of exposure would be only 200 μJ / cm 2. An obvious issue is that 50 μm diameter droplets are required to light cure to a level sufficient to prevent surface diffusion and the intensity and level of exposure (assuming 20% cross linking in more accurate data). It is also necessary to determine the resulting influence of the change in viscosity at the exposure level and the impact properties of the viscous droplets on solid surfaces. UV cured polymer ink systems are currently used for desktop publishing and wide format printing of color text and graphics. The standard process is to print polymers on porous paper or treated paper or conventional / treated flexible plastics and allow ink droplets to reach diffusion equilibrium prior to irradiation with a suitable wavelength of light. This application discloses processing and system properties that can be applied to copy treatment of ink jet printable inks or fluids, particularly UV curable inks, in terms of increasing print resolution.

The inventor defined a design for a high efficiency etch mask printing system based on both open reel and robot substrate transfer methods. This is accomplished by using multiple sets of printheads to allow multiplicity of workstations (see FIG. 9) to be operated along the open length of the plastic sheet held between two tensioned "feed" and "receive" drums. .

Radiation curing sources based on light emitting polymers (LEPs) used in striplights or full area lighting devices may be utilized (see FIG. 10). Radiation curing is accomplished as a wide area process by using thin film inorganic or organic luminescent materials. Thin film device designs define the wavelength band to be emitted by the device. The emission can be adjusted to suit the particular wavelength or wavelengths. Discrete bands or bands of wavelengths can be achieved in device manufacturing. Band or band focusing or defocusing can be accomplished with the lens configuration. Convex lenses can be deposited using drop-on-demand technology.

11 shows a means of dynamic print imaging using a linear imaging device integrated directly into an ink jet print head. Subsequent systems use a fixed width charge transfer element (CCD) [or xy addressable] using a co-occurring nozzle-to-pixel array that monitors printhead response in real time related to batch precision and throughput (substrate reprocessing). We will use droplet impact imaging in situ using an image array. Identification of defective nozzles (dot / nodot identification) will allow redefinition of the printing image to compensate for defective nozzles. The imaging array is placed in close proximity to the printhead nozzles to obtain localized individual nozzle droplet dot responses. Another preferred embodiment of the present invention uses a simple organic photoconductive pixel array with an organic lens array integrated at the location of a CCD or x-y addressable metal oxide semiconductor silicon photodiode imaging array.

12 illustrates a means for improving throughput by combining etch mask pattern recognition and software based printed pattern overlay comparison using a wide area organic photoconductive (photodiode) array. Large areas can be directly compatible with 1: 1 image mapping, allowing a fully printed circuit board to be imaged without the need to scan the camera on the board surface. The software then compares the mask pattern CAD image with the image captured from the wide area organic photoconductor array. Found defects are identified by vector arrangement, and if the defects are missing portions of the mask, the ink jet printhead can be moved to the correct position to repair the track.

13 shows a bimorph electromagnetic radiation shutter. The shutter assembly uses a silicon micromachined structure (MMS) that provides the required nozzle aperture, which is specifically compared to the actual drop diameter. The inner surface of the shutter assembly (silicone MMS) is non-wetting with ink and removes excess ink from the nozzle plate that must be moved to catch the reservoir at the edge of the printhead, which is periodically emptied using a simple vacuum suction nozzle. A series of nozzle plate cleaning wiper blade-like structures are fabricated thereon, including a fluid duct that easily flows to allow. In operation, the shutter assembly functions normally to cover the nozzle array, using triple blade sealing on one of the nozzle sides. The wiper blade type sealing strip is sealed at both ends to form the enclosed capping configuration. The injection sequence will be as follows.

1. Standby mode where the shutter assembly is placed to cover the nozzle array.

2. The nozzle plate is cleaned by vibrating the bimorph shutter back and forth.

3. Printhead spray test with 50 pulse (50 drops) bursts for all nozzles in the array. Excess fluid is discharged toward the catch reservoir during subsequent vacuum suction removal.

4. Remove excess fluid from the catch reservoir.

5. Download the CAD image to be printed.

6. Use the leading edge of the drive waveform to generate a bimorph shutter waveform to move the shutter to the firing position.

7. When the shutter reaches the injection position, droplets begin to form at the nozzle exit.

8. When the droplets are ejected and the shutter assembly is cleaned, the shutter closes immediately, cleaning the nozzles between each sprayed droplet.                 

Subsequent printheads will use drive waveforms that actually control solid-state semiconductor laser pulse activation for sequenced timing sequences for droplet injection, bimorph nozzle shutter micropositioning, and “smart” fluid injection module operation. Nozzle drive pulses can be monitored in a suitably manufactured printhead that enables the following:

* Modification of injection delay to impact batch precision

Gradually change the spray parameters to maintain the properties of a given series of drops.

* Generation of test pattern printing and image grabbing and interpretation to enable software handling of batch precision versus specific nozzle drive characteristics.

In situ environmental and radiation shutter assemblies also serve as:

Real-time pulsed plasma electrode providing surface pretreatment close to the drop landing area.

* Printhead Vacuum Detonator.

The wiper blade nozzle plate cleaning material must be compliant, tough, adhered to the substrate, and chemically stable in contact with the fluid / ink system being injected. Typical materials include silicone, polyimide, PTFE, rubber, neoprene, polyvinyl and viton. The surface of the wiper blade can be locally hardened (see FIG. 14) to provide better cleaning action and resistance by exposing the surface to a beam of high energy ions (ion implantation or plasma immersion implantation). A typical process may use 10 ¹⁵ ions / cm 2 of nitrogen injected into the Teflon coating at an energy of 70 keV to generate ions of total 231 nm.

Multiple droplet ejection waveforms and sequences that provide variable speed radiation cured printing, including high speed, may be required to support a wide range of applications using this technique. High speeds also include when piezoelectric or relaxr type ink jet printheads are operated in a resonant mode (approximately 1 MHz).

Prior to printing an etch mask or surface relief pattern, surface pretreatment may be required to moderate adhesion and limit surface wetness. Means for providing surface cleaning, including dry means, are based on localized generation of ozone, UV exposure, acid or alkali spraying from a spray head or ink jet printhead, or solvent dispensed from a spray head or ink jet printhead. Shall be. Many manufacturers manufacture printed wiring board substrate materials. In most cases the metal is copper and is one of a thin layer of vacuum or adhesive on a substrate of choice (FR4, PTFE, plasma, etc.). This necessarily means that the surface quality of each other differs either in the state of fine scale or in planarity (reinforcement fiber, foil rollyl stress line, etc.) on the macro scale.

* Ozone plasma

* Specific plasma

* Localized UV Probe                 

All substrate pretreatments should be considered for compatibility with both wet and dry etching methods. This is because the etching mask printing process can be applied to a surface other than copper, which is not necessarily compatible with the high resolution wet etching process. It is a preferred embodiment to consider printing the negative image of the image to be achieved with the masking layer. This negative image is a non-wet coating that allows limited diffusion of masking material. For this technique, it is important that printing parameters and masking inks be selected to prevent splashing and excessive inertia effects in droplet impact. If this occurs, ink diffusion beyond the negative non-wet control print may result in "over wash" if the receiving angle is high.

A preferred embodiment of the present invention can provide a real time height positioning of the ink jet printhead using a bimorph positioning transducer that moves the printhead in the z axis (see FIG. 15). The height adjustment is preferably at 50 to 200 μm. The tip deflection distance of the bimorph cantilever is proportional to its length as x (L, V): = 2.3 / 2.d ₃₁ .L ² / t ² .V (t = bimorph thickness; L = bimorph Length: d ₃₁ = charge constant [ie, -306 × 10 ⁻¹² CN ⁻¹ for Morgan Metlock PCK5]; V = drive voltage. For a drive voltage of 100V and a bimorph length of 15 mm, the expected tip deflection would be approximately 100 μm at a free resonant frequency of 1200 Hz. The bimorph height control of the printhead uses a semiconductor laser height range finder with bimorph feedback. The bimorph is positioned at both ends of the printhead. Real-time height adjustment for ease of use is very close to proximity printing smaller than or equal to 250 μm. Real-time position is a direct result of feedback signals from electro-optical (laser [range finder principle] or LEDs associated with phototransistor or photovoltaic pairs) or capacitive sensing elements. To the limit, the height control will lead to the shortest moving contact, and the ink is not ejected as droplets but is moved onto the substrate surface through a characteristic wet action where the droplet “necking” exerts an induced pressure to break. Head height control may be due to inductive sensors that react to the metal substrate.

It is anticipated that temperature and air control of the working area adjacent to the printhead will be required. Such localized air control (see FIG. 16) provides an inexpensive means of controlling the deposition required due to air control associated with the entire printed area. The control zone is defined as the printhead nozzle plate on the + ve z axis and the length and width of the nozzle plate including the element allowing the edge effect, and a limited area as the substrate surface on the -ve z axis. In one embodiment, this area is achieved by enclosing the bellows type printhead and integrated dot imaging and radiation hardening source that provide positive air pressure or a designated inert or reactive gas injection (gas is heated or cooled). Can be. Weak vacuum may be supported in the bellows, using a dry vacuum pumping configuration. The bellows structure can be made of a soft, flowable, low gas effluent, electrically conductive material that supports both surface cleaning and surface electrocharge decomposition. Etch mask material printing and curing will settle within this envelope. Proximity printheads facing the substrate spacing require the following considerations.                 

* Potential across the printhead-to-substrate gap, such as bound to the processing bellows.

Vacuum suction and air flow induced in the pressure differential in the treatment bellows.

* Airflow filtering to minimize dust between printhead-to-substrate by filtration of air or gas used in treatment bellows. If vacuum is used, inlet dust will be minimized by the presence of bellows.

 For high efficiency printing, it is desirable to use a wide range of format printing capabilities by making printhead enclosures that can accommodate multiple printheads. This is accomplished by butting together a series of printheads and a common nozzle format. This requires that the pattern with the equilibrium side not be affected even if the number of nozzles is increased. Butting errors need to compromise such prints, integrating a common nozzle plate. The closely coupled (butted) printhead is aligned in the x-y-z axis by utilizing the piezoelectric positioning of the He-Ne laser assembly, which can be removed once the alignment is complete and the placement is locked in position. Such positional accuracy is essential if the geometric limits of the etch mask pattern must be kept past the substrate surface to be coated. Another preferred embodiment uses a piezoelectric locator that uses a feedback loop derived by imaging the original location of the sprayed droplet on a series of test patterns that are imaged and overlaid on the test pattern to define the nature and extent of feedback control required. Is to use multiple printhead alignments.

Ink formation for optimization of mask pattern line width control has been learned. It has been shown that the glass transition temperature T _g affects the hardness and temperature stability of the flowing acrylic containing ink without adversely affecting the viscosity and surface tension of the ink. It has been experimentally shown that the change in volume-to-surface photoinitiator rate also affects the cure rate. A change in photoinitiator ratio of 1: 1 to 4: 1 (surface: volume) was shown to promote rapid curing. Too high surface initiator content promotes blocking in the nozzle before the droplet is actually sprayed. The range of fluid properties should be optimized for the line width and cross-sectional profile of the mask pattern, regardless of whether the ink rate is solidified by air dry, or by radiation or curing methods, to provide a minimum of droplet surface diffusion. Such shapes include:

Droplet velocity = 0.1 to 10 [m / s]

Dynamic viscosity = 1 to 100 [mPa.s]

Heat of Evaporation = Low [J / mol]

(Subject to fluid)

Fluid concentration = 0.5 to 1.8 [kg / m 3]

(Subject to fluid)

Material Solid Content = 0.0001 to 100 [%]

Static contact angle with substrate = 0 to 120 [ ^o ]

Substrate temperature = 230 to 370 [K]

Surface tension = 35 to 76 [mN / m]                 

The ratio of volume to surface photoinitiator affects the coagulation rate. This is the case for the surface tension and glass transition temperature T _g of the polymer used in the mask. In a preferred embodiment, the ink formation is compatible with the operation of the integrated fluid nanoscale filter, based on the ramp wave fluid movement principle, where the fluid flows through the permeable silicon etched (chaos) filter structure. The ramp wave electrode is a design that provides fluid flow through the filter and fluid supplied to the nozzle. Provides precise metering and arrival timing of fluid in the nozzle bore.

The present invention utilizes a low temperature (no need for any auxiliary cooling), proximity to the printhead assembly [x and y axis] and substrate surface [z axis], microwave-initiated gas emission radiation sources (extended time or strongly Provide a means of wide area polymer crosslinking (for solidified etch mask material solidification) (see FIG. 17). Gas emission radiation sources provide illumination on the substrate surface because the top surface of the assembly is coated with a thin film that reflects light behind the emitter (light path), thereby increasing coupling out efficiency, while the bottom surface is coupled to the substrate surface. A surface relief pattern is fabricated therein that allows the emitted light to out to irradiate the mask material. The surface relief required to extract the plasma emitting photons of the desired wavelength (gas characteristics) can be a dispersion structure such as a diffuser, dot matrix, or moss-eye lens matrix.

Preferred embodiments use convex lenticular arrays, where wall angles of angles less than or equal to 90 °, nearly square cross-sectional projection widths, heights, and wall slopes affect the efficiency of the coupling for a specified wavelength of light. do. The light path and gas emission (plasma) confinement structures consist of quartz or similar UV transition materials. Proximity assemblies aid in the transfer of photo energy (μJ or mJ / cm ² ) without significant loss along path length (inverse square law effect). In a preferred embodiment, full region microwave initiation gas supported supported UV irradiation will be used for the final cure exposure of the large area panel. The grating structure described above is designed to match the wavelength of light, represented by the gas properties used. Such gases include Ar, He, Cl, Xe, O ₂ , N ₂ , and mixtures thereof.

Another preferred embodiment of the lattice structure is a series of squares that mimic an arrangement of "castle towers" that form a bend. The arrangement of the mask-space ratio and the mask rectangle (height, width and wall slope) depends on the wavelength of light to be combined at the window surface.

In a preferred embodiment, reflective surfaces (thin aluminum, gold, etc.) may be included outside of the exposure top (roof) to increase the efficiency of the exposure apparatus output. This UV curing device operates at power levels that do not require noisy, bulky air cooling. Recirculation of gas cooling can be introduced if high power applications are required.

The designated nozzle plate arrangement can affect the placement control of droplets ejected from the nozzle arrangement. Not all printheads eject ink drops from adjacent nozzles at the same time. This is because the mode of operation is a piezoelectric based ink jet printhead which may be due to bending, pushing, or shearing action. If shearing action (ie Xaar XJ series printhead) is used, the nozzle stagger must be confined to the nozzle plate for straight text printing. In order to achieve droplet adhesion that results in a well defined line, it is necessary to vary the droplet spacing by operating the printhead outside the standard parameter range. For the Xaar printhead, the ejection delay forces the substrate motion leading to a series of drops that are printed on the stagger. In order to achieve a straight line process, a number of potential solutions can do the following.

1. Reprogram the cycle time delay to another fixed value.

2. The nozzle plate is made of another nozzle stagger.

3. Change image processing to increase resolution.

4. Reprogram the chip into a single cycle waveform, ie all channels start at the same time and use image processing to provide the fact that this is not real (including print speed).

A preferred embodiment of the present invention provides a series of nozzle plates designated to provide ink jet printing of a mask pattern with parallel lines in all directions in the x-y plane.

The present invention can provide a method of ink jet printing an electrode surface solder mask pattern. In this example, the method of forming the solder mask is similar to the method of forming the etch mask described above, except that the choice of ink formation must reflect the high temperature limitations applied to the solder dip coating and thermal wave solder reflow processes. Do. The solder mask is designed to provide a means of limiting the area of a suitably treated surface that can be coated with a solder metal such as an In, Sn Pb-Sn alloy or the like. Soluble materials that can be used as the solder mask include silicone, polyimide, PTFE and epoxy.

The present invention can provide a method of achieving a 3D etch mask using an ink jet printing method. Many device fabrication applications require products in the form of variable build heights or etch depths. An ink jet printing process may be used to define such shapes using solidified droplets in specific areas or multiple paths of the pattern where the pattern to be printed may differ each time. In both cases, the resulting mask has a local change in height profile. The mask can be left as a solid structure to form a 3D relief structure on the surface or used in an etching process so that the mask material can be gradually etched in excess time by the corrosive. Progressive etching promotes local variations in etch depth, particularly for reactive ion beam or plasma dry etching processes. The mask material may be constructed in a single type with a mask consumption rate to expose a surface undergoing a controlled etch since the gradual etch rate is constant and the etch depth change is due to variations in thickness. The mask may be composed of a number of materials that differ in etch rate (etch resistance) from the corrosion solution used. In this case, the etching can be controlled on the x, y, z (depth) axis by defining a fully strengthened etching mask at a specific position of the mask build.

UV (or other energy / radiation) line sources can be used to fabricate an etch mask pattern. Such line sources provide a uniform area of radiation (UV-visible-IR-electronic) exposure and a specific area of exposure beyond the width of the selected printhead and occur on a specific location relative to the drop impact area for exposure. May be required. The line source may use fanned fiber bundles to provide a single line of fibers of individual diameters of 0.25-1 mm (see FIGS. 18-22). The fiber lines adhere and adhere directly to the polyimide sheet support material, which provides some strength and ease of handling. The fluidity of the fiber and support sheet allows the fiber bundle to be formed at the correct position and angle for radiation exposure at or near the drop impact area. The front side of the fiber bundle may be attached to it with a convex lens that provides a high light homogenization across the entire array of individual fibers. Multiple fiber bundles can be constructed that provide a series of irradiated areas that are separated to provide pulsed exposure at / during a set time interval as substrates that overlap or traverse the irradiated area to form a wide area exposure.

Alternatively, local curing can be achieved using xenon lamps with various duty cycles, operating frequencies and spectra (by changing filter usage and / or doping of lamp gases and / or lamp power supplies).

The present invention can provide a method of overlaying (tenting) a printed wiring / circuit board plated through a hole using an ink jet printing process. Typical holes are 0.1 to 1 mm in diameter. The tenting process can be approached in two ways: so-called plated hole in-fill or surface tension coating.

The infill process uses a number of droplets to cause droplets to fill the plated holes under capillary action. UV curing solidifies the fluid to form a solid plug.                 

The surface tension coating process should have a droplet size larger than the size of the hole to be overlaid. Moreover, since the surface tension of the fluid must be controlled to limit the degree of surface wetting, the fluid surface tension restoring force will attempt to make the hemispherical fluid covering the plated holes as desired. The fluid solidifies again by exposure to radiation (UV-visible-IR-electrons).

The techniques described above can be extended to methods of removing ink jet printed UV cured acrylic containing etch masks. The removal process can be either dry or wet. The dry process involves a variety of gases including argon, oxygen, argon-oxygen mixtures, CF ₄ -oxygen mixtures, argon-water vapors, etc. (inert gas rare earth oxides; reactive gases are treated with hydrogen, oxygen, chlorine, fluoro, etc.). Use plasma based materials. Sulfur gases, such as argon, provide ions that bombard the masking material in terms of separating the surface / surface close area (called the "change layer"). This separated zone not only provides direct access of such species to the exposed carbon backbone of the acrylic containing reaction, but also allows for easy migration of reactive species to the volume of masking material. The negative charge of counter species (i.e., CC, CH, CO, CF, etc.) combined with energy from the outside dispersed by hot (high energy) ions is allowed to allow a high rate of etch containing acrylic to occur with a position exchange action. Provide the necessary thermodynamics. Etch rates in excess of 1 μm per minute can be easily achieved.

Wet processes can use both aqueous and non-aqueous solvent systems. The aqueous based chemical caustic is mainly caustic based (a typical process is diffusion injected through a roller of 5% NaOH in H ₂ O at 30 ° C.). Non-aqueous solvents for removing the acrylic containing mask include the following.

* Chloroform (Solubility)

Dichloromethane (expansion and solubilization-quick removal)

Tetrachloromethane (dissolution)

* Chlorobenzene (expansion)

* 1,1,2-trichloroethane (soluble)

N-methyl pyrrolidinone (expansion-low process)

Similarly, the technique can be applied to a dry etching resistance, ink jet printing method of an inorganic etching mask. Although the etch mask process described above uses acrylic containing (organic) materials, the ink jet printing method equally provides etch masks based on inorganic or mixed organic-inorganic fluid systems. In such cases, the properties of fluid and chemical stability still apply to the printhead material and the nozzle non-wetting coating.

The method of solidifying droplets can be represented by the fluid system used. Organic-inorganic fluids (ormocer-organically converted ceramics, sol-gels, metal-organic, etc.) can use radiation curing such as UV. However, depending on the application, other levels of coagulation will be required, using thermal percolation. In this case, a rapid thermal method can be applied to the treatment area using proximity survey or sequential movement. Thermal annealing processes infiltrate the mask material and drive out high etch rate organics. Subsequent materials have a certain degree of radiation (plasma) hardness that makes them suitable for dry etch masking applications.

The present invention extends to a drop radiation curing method using a dual printhead configuration as a common integrated radiation curing source (see FIG. 22). This configuration has a copy source located at the outer edge and center of the dual back-to-back printhead configuration. This allows the printhead to print in a bidirectional mode, providing the same degree of copy exposure regardless of the front or back print.

The above-described technique can be applied to the non-electrolytic and electrolytic plating bath resistance, the ink jet printing method of the etching mask pattern. The printing method is the same as for the printed wiring board etch mask printing. The difference lies in the need to construct a mask pattern that is three-dimensional in the choice and properties of the materials used. 3D printing has been described above. The choice of mask material depends on the nature of the electroless and / or electrolytic bath solution. Typical materials include epoxies, polycarbonates, silicones, PTFEs, polychlorotrifluoroethylenes, polyimides, polyisoprene and polypropylenepolystyrenes, and the like.

Additional plating etch masks may be formed using ink jet printing. This is a specific use of localized height builds, as covered under 3D printing.

Additionally, high resolution etch masks can be formed using ink jet printing. High resolution has different meanings depending on the application serviced. For the purposes of this disclosure, high resolution means shape sizes smaller than 10 μm.

The electrically conductive masking layer can be formed using the technique described above. Such masking layer may be left after use as a seed layer for the electroless / electrolytic plating of the electrode pattern. The masking layer may be carbon based or metal acetate based (ie, palladium) based to affect specific conductivity and chemical interfacial behavior before plating with the metal of choice.

A decorative surface etch mask can also be formed. The decorative surface can be based on the characteristics of the ink used to form the surface relief pattern. For example, an ink loaded with optical particles reflecting light upon solidification at a wavelength different from the exposure wavelength and angle may be used. Such systems can be used as security devices due to the unique nature of the dust distribution in solids that can be imaged and recorded as security signals.

The mask pattern may be formed based on chemical attachment transfer (see FIG. 23). Chemical attachment may be via chiral or hydrophilic action on the surface. The associated energy provides a means to deliver a known volume of fluid from the partially sprayed droplets that breaks the droplet binding force under controlled conditions. Computational fluid dynamic modeling indicates that such fluid transfer (flow science) does not occur under certain fluid surface tension and substrate surface energy conditions.

A single panel printed wiring board (PWB) back-to-front auto resist etch mask can be formed (see FIG. 24). The process may use a butted linear array of two facing printheads or printheads, aligned in relation to one another, for example using a He-Ne laser beam and a silicon diode photodetector. Alignment is affected using the azimuth of the piezoelectric bimorph positioning device (or similar) on the x-y-z axis and the printhead / printhead array. If alignment is affected, the panel can be carried in an intermediate frame between the printhead (or array) and the dual prints achieved on both surfaces to be recorded at a high degree.

An almost vertical wall mask pattern can be formed. Computational fluid dynamic modeling (from FlowScience's Flow 3D modeling software) of drop-jet inkjet printheads interacting with solid surfaces has suggested that single dots can be created in the form of sidewalls very close to vertical. The drop spacing and the solidification state of the previous drop, combined with the impact rate and ink viscosity of the drop, affect the adhesion rate to form a line. In order for the line to have a vertical sidewall profile, it is necessary for the coalescence process to occur within the time it takes for the droplet material to diffuse to the width of the solidified droplet (ie less than or equal to 10 ms).

An ion implantation mask may be formed (see FIG. 25). The purpose of the masking material is to protect the surface from high energy ion beams under a mask. The energy range is 10 eV to 50 eV. The thickness of the masking layer will depend on the energy of the beam to be irradiated. For high energy, the expected mask thickness will be less than or equal to 10 μm.

The invention can be extended to a method of generating a surface relief pattern on a surface. Such an embossed pattern can be a containment well mask used in the manufacture of single or multiple color light emitting polymer displays (see FIG. 26). Other display devices using such containment wells include an inorganic lanthanide element dye or an organic particulate dye structure.

The present invention can also be extended to a method of making a separate spacer pattern (see FIG. 27). The separated spacer is used to separate the flat panel display device into two parts, known or precise heights. An example is the use of known conductive and secondary electron emitting spacer materials for use in vacuum based field emission displays. Another example is the separation well structure used in liquid crystal displays. The well structure includes an ink jet printed or vacuum injected liquid crystal to affect the filling of the well.

In other configurations, the etch masks can all be formed using dry, charged toner, photo transfer processes. This is a photocopy application of the toner, which is a nano or microcapsule / particulate / beads system that provides the diameter and material properties needed to charge the deposit on the toner and the particle transport to the substrate to be patterned with the photoconductor. Computer-generated images (CGIs) are supplied to light emitting polymer (LEP) displays that irradiate photoconductive (receptor) drums / plates containing electrostatic charge at a particular wavelength or frequency band. As in a standard photocopier, the electrostatic charge (amount) of the photoconductive drum / plate is weakened where light from the LED display is incident. The roller system moves toner (negatively charged) to the image area on the photoconductive drum / plate. The substrate is in proximity and the toner moves from the photoconductive drum / plate to the substrate. The substrate is given a positive charge strong enough to draw an image pattern on the toner away from the photoconductive drum / plate and to provide sufficient electrostatic force to hold the toner in place. In this regard, the standard photocopier process may continue the so-called toner fusing onto the substrate past the heated roller pressure. Alternatively, the toner may be processed using in-situ high speed thermal / infrared radiation (pulse or continuous irradiation) processing means to reflow microcapsules / particles / beads to affect material adhesion. For example, it is contemplated that the toner microcapsules / particles are in fact low temperature (<200 ° C.) thermoplastic solid beads. The charged particles melt by introduction of temperature. The degree of melting is sufficient to allow coalescence without excessive surface wetness (reflow). Removal of heat causes the thermoplastic to resolidify, forming a desired etch mask pattern. It is contemplated that hollow capsules will be used to contain certain materials (ie, polymers, inorganics, etc.). By exposure to irradiation / treatment air, the shell of the microcapsules will disintegrate to reveal the interior of the material. With controlled viscosity and surface tension (temperature dependent), this material combines with the material from the closest capsule flowing in the broken bondage to form the required pattern image. Such an image is not limited to the etching mask pattern but may form part of an organic electronic or optoelectronic device. CGI pattern migration means that no mask is required for this process.

Some examples of practicing the invention will be described.

General aspects

1. Interlaced and printhead addressing capabilities of images

The circuit image is generated on a CAD / CAM system and transferred to the mask print system in a standard vector format such as RS-274X Gerber. The file containing the circuit image is converted to raster format to produce the correct file format for the printhead operation.

In addition, raster images are divided into equal areas or laser widths to be printed. The image is further subdivided into multiple additional interlacing paths within each area to produce greater image resolution.

Channel stepping is an important issue in the field of etch mask printing by allowing increased addressability of droplets on the substrate than is produced using standard shaped printheads.

The printhead is represented by the following values.

1 / path number × nozzle spacing

For example, for a printhead with 180 dpi nozzle resolution, image resolution of 360 dpi can be achieved using two paths within each area with combined 1/2 channel (70.5 μm) channel steps. The image will be different for each path in the area, and in the case of two paths each path image will contain alternate pixel lines.

For the 720 dpi droplet addressing capability of the substrate, four (ie, 720/180) paths are required, so that for 720 dpi substrate addressing, the printhead step index is 1/4 x 141.1 µm = 35.275 µm.

In the case of four-path processing, each successive image will contain all 4 ^th pixel lines.

Subsequent printhead developments will aim to provide smaller drops of 16 levels of grayscale and 360 dpi nozzle concentration. In the case of 2880 dpi drop address capability on the substrate, 8 (ie 2880/260) paths are required. For the 2880 dpi substrate address capability, the printhead step index is 1/8 x 70.6 mu m = 8.82 mu m.

Moreover, this interlacing process is such that subsequent paths in the area are executed using different settings of the nozzles. For example, when using a 500 nozzle printhead, the image is divided into areas / paths between 400 and 496 pixel lines. The printhead can be moved by the total number as well as the fractional steps between the channels, with software adjusted image states to accurately realign the image. This method minimizes the impact of nozzle changes or failures by reducing pinhole formation and open circuit failure rates in the produced circuit.

For example, the printhead may be represented by 5 1/4 × nozzle spacing between paths with the printhead channel offset parameter increased to 5 to reorganize the image.

2. General copper lamination pretreatment

All forms of copper lamination such as inverted, double and chromate treated on standard HTE, FR4 and PET substrates are susceptible to certain pretreatment situations. Perchloric acid microetching is used to remove the antioxidant layer. Alternatively, permitting, brushing, and polishing the surface can provide satisfactory results. The surface roughness is usually 0.1 to 5.0 mu m, preferably 0.1 to 1.0 mu m.

A proprietary anti-tarnish spray according to the adhesion promoter is sprayed onto the substrate.

The surface energy of the pretreated board is 24 to 35 dynes / cm, preferably 26 to 28 dynes / cm. Finally, teki rollers or ionisers are used to remove all dust spots from the pretreatment substrate prior to printing.

3. General conditions

Etch mask printing is preferably carried out in a dust and vibration free environment of ambient temperature at 10-40 ° C., preferably 20-30 ° C., at ambient humidity between 20-70%. The printhead temperature for all examples was 30 to 60 ° C, preferably 35 to 45 ° C.

Example 1: large size

Large size operations (greater than 250 μm) are performed using the Xaarjet XJ500 180 dpi printhead, are designed to print UV cured acrylic acid based fluids and consist of nozzle staggers between 15 and 47 μm. The stagger used for this example was 23.5 micrometers. The printhead had 500 nozzles and was produced in a drop size of 70 pL. The printhead was used at a height of 0.5 to 2.0 mm on the substrate, preferably a height of 0.75 to 1.25 mm. The printhead address capability is 180 to 540 dpi, preferably 360 dpi, and printing was performed in two directions at a printing speed of 168 to 506 mm / s, preferably 282 mm / s. Drop impact / UV local cure delay was 10-2000 ms, preferably 50-300 ms.

Example 2: medium size

Medium size operations (150 μm or larger) are performed using the Xaarjet XJ500 360 dpi printhead and are designed to print UV cured acrylic acid based fluids and have a nozzle stagger between 6 and 23.5 μm, preferably 11.8 μm. . This head has 500 nozzles and is produced in a drop size of 21 picoliters. The printhead was used at a height of 0.2 to 2.0 mm, preferably 0.75 to 1.25 mm on the substrate. The printhead address capability was 360 to 1440 dpi, preferably 720 dpi, and the printing was processed in four directions in one direction at a printing speed of 60 to 506 mm / s, preferably 60 to 282 mm / s. Drop impact / UV local cure delay was 10-2000 ms, preferably 50-300 ms.

Example 3: small size

Small size operations (at least 50 μm) are carried out using an Xaarjet XJ500 grayscale (8 level) printhead with a nozzle stagger between 3 and 11.8 μm, preferably 6.0 μm, for printing UV cured acrylic acid based fluids. Designed. This head has 500 nozzles and produces droplet sizes between pico liters per 5 and 6 levels. The printhead was used at a height of 0.5 to 2.0 mm, preferably 0.25 to 1.25 mm on the substrate. The printhead address capability was 360 to 1440 dpi, preferably 720 to 1440 dpi, and printing was performed at a printing speed of 43 to 350 mm / s, preferably 87.5 to 175 mm / s, depending on the number of printheads used. Treatment was in 4 to 8 routes in both directions. Drop impact / UV local cure delay was 10-2000 ms, preferably 50-300 ms.

Future printhead developments that offer 16 levels of grayscale at smaller droplet sizes and 360 dpi nozzle concentration will expand the address capability to 2880 dpi, with print speed limited to the printhead's firing frequency. Printing will be in the forward and reverse directions of the eight print paths (divided by the number of printheads used).

4. General UV Ink Curing Condition

The ink jet etch masking system comprises: (1) a local curing source in proximity to the printhead having a strength of 1 to 300 mW / cm ² ; And (2) two different UV curings of the final, full board curing source of intensity between 100 and 300 W / linear inch with a total energy of 0.5 to 4 J / cm ² , preferably 1 to 2 J / cm ² . Consists of the source.

Generally, curing is preferentially treated under partial oxygen with reduced air, but is not limited to the positive pressure of nitrogen or other inert gas in the curing zone. The residence time under final UV curing is 1 to 10 s.

Alternatively, local curing can be achieved using xenon lamps with variable duty cycles, operating frequencies and spectra (filter usage and / or doping of lamp gas and / or changing the power supplied to the lamp).

5. Etching and Mask Pattern

The copper laminate substrate in full mask pattern is processed through a standard spray conveyor etch system using either acidic or alkaline etch chemistry.

The etch mask is removed using an alkaline dip, preferably potassium hydroxide or sodium / 2 aminoethanol system, with agitation such as spray dipping at a temperature between 20 and 50 ° C.

The invention has been described above by way of illustration, and it will be understood that modifications of the content may be made within the scope of the invention.

Each feature has been described in the specification, and the claims and drawings may be provided independently or in any suitable combination.

Claims (105)

delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete A method of forming a masking pattern on a surface using a drop-on-demand printing technique that deposits a plurality of droplets of deposition material onto a surface from a droplet deposition apparatus to form a masking pattern, the method comprising: Operating the deposition apparatus to deposit a plurality of liquid droplets through a working zone located between the deposition apparatus and the surface to form the masking pattern; At least one droplet of liquid deposited on the surface diffuses and coalesces with at least one other droplet of liquid deposited on the surface; and Locally exposing the deposited liquid droplets to electromagnetic radiation within the working zone for a predetermined time after the liquid droplets are deposited, wherein the exposure of the liquid droplets changes at least one liquid property of the deposition material Forming a masking pattern on a surface of which the solidification rate of the masking pattern is controlled by stopping the coalescence. 78. The method of claim 77, wherein formation of the masking pattern is controlled such that the masking pattern has a predetermined structural characteristic. 78. The method of claim 77, wherein said zone of action extends from said deposition apparatus to said surface. 78. The method of claim 77, wherein relative movement between the deposition apparatus and the surface is performed such that the zone of action passes through the surface while the masking pattern is formed. 78. The method of claim 77, wherein the local environment of the zone of action controls the coalescence of droplets on the surface, controlling the diffusion of droplets on the surface, or controlling coalescence and diffusion of droplets on the surface. Characterized in that it is controlled. 78. The method of claim 77, wherein the local temperature of the zone of action is controlled to control the rate of solidification of the droplets on the surface. 78. The method of claim 77, wherein the local atmosphere of the action zone is controlled. 84. The method of claim 83, wherein at least a partial vacuum is performed in the zone of action to avoid contamination of the droplets while the droplets migrate from the deposition apparatus to the surface. 84. The method of claim 83, wherein an inert or reactive gas enters the working zone during droplet deposition. 78. The method of claim 77, wherein the local exposure duration of the action zone to electromagnetic radiation is controlled to regulate the diffusion of droplets on the surface, thereby controlling the shape of the masking pattern. 78. The method of claim 77, wherein the intensity of the electromagnetic radiation is controlled to control the diffusion of the droplets on the surface, thereby controlling the shape of the masking pattern. 78. The method of claim 77, wherein the zone of action extends to the surface, and local exposure of the zone of action to electromagnetic radiation is followed by deposition of the droplet through the zone of action. 89. The method of claim 88, wherein the time between deposition of the droplet on the surface and the local exposure is controlled to control the diffusion of the droplet on the surface. 90. The method of claim 89, wherein said time is between 1 and 2000 ms. 78. The method of claim 77, wherein said electromagnetic radiation comprises at least one of ultraviolet, visible, infrared, microwave, and alpha particles. 78. The method of claim 77, wherein following the local exposure of the zone of action to electromagnetic radiation, the deposited masking pattern is entirely exposed to electromagnetic radiation such that the deposited droplets are cured. 78. The method of claim 77, wherein the distance between the deposition apparatus and the surface is controlled during droplet deposition to control the time it takes for the droplet to progress from the deposition apparatus to the surface. 94. The method of claim 93, wherein the distance is 0.5 to 2 mm. 78. The method of claim 77, wherein controlling surface energy of the surface prior to droplet deposition, and / or at least one of polishing, polishing, ozone treatment, plasma exposure, and surface coating is performed prior to droplet deposition of the surface. The method comprising the step. 78. The method of claim 77, wherein the masking pattern is a three-dimensional masking pattern, the masking pattern comprising a plurality of deposition material layers, wherein the plurality of deposition material layers are sequentially deposited on the surface. 97. The method of claim 96, wherein the masking pattern is formed by a plurality of droplets deposited at a plurality of deposition locations on the surface, the droplets being deposited in each of the locations in turn. A method of forming a spacer pattern on a surface using a drop-on-demand printing technique that deposits a plurality of droplets of deposition material onto a surface from a droplet deposition apparatus to form a spacer pattern, the method comprising: Operating the deposition apparatus to deposit a plurality of liquid droplets through a working region located between the deposition apparatus and the surface to form the spacer pattern; At least one droplet of liquid deposited on the surface diffuses to coalesce with at least one other droplet of liquid deposited on the surface; and Locally exposing the deposited liquid droplets to electromagnetic radiation for a predetermined time after the liquid droplets are deposited, wherein the exposure of the liquid droplets changes the at least one liquid property of the deposition material to stop the coalescence. Controlling the rate of solidification of the spacer pattern. A method of forming a circuit pattern on a circuit board using a drop-on-demand printing technique that deposits a plurality of droplets of deposition material onto the circuit board from the droplet deposition apparatus to at least partially fill through holes formed in the circuit board. As the method, Operating the deposition apparatus to deposit a plurality of droplets through an action zone located between the droplet deposition apparatus and the surface to at least partially fill the through hole; Diffusing at least one of the droplets deposited on the surface to coalesce with at least one other droplet deposited on the surface; and Locally exposing the deposited droplets to electromagnetic radiation for a predetermined time after the droplets are deposited, the exposure of the droplets altering at least one liquid property of the deposited material to cause liquid on the circuit board to Controlling the filling of the through hole by stopping coalescence of the droplets. A method of forming an embossed pattern on a surface, the method comprising: Selectively irradiating a charged roller to selectively remove the charge of the roller portion; Using a drop on demand printing technique to deposit a plurality of droplets through the action zone located between the deposition apparatus and the roller to the charged portion of the roller in the droplet deposition apparatus; Diffusing at least one droplet deposited on the roller to coalesce with at least one other droplet deposited on the roller; Controlling the solidification rate of the pattern formed on the roller by locally exposing the deposited droplet of liquid to electromagnetic radiation to capture the coalescence of droplets on the charged portion of the roller; And Transferring the deposited material from the roller to the surface to form an embossed pattern on the surface. 101. The method of claim 100, wherein the embossed pattern formed on the surface is heated to become material coalescing. 101. The method of claim 100, wherein the relief pattern formed on the surface is radiation cured to affect the coalescence of the material. A deposition chamber containing the deposition material, a discharge nozzle fluidly connected to the deposition chamber, and a droplet of deposition material on demand from the deposition chamber to the surface through the discharge nozzle to form a masking pattern Means for defining a working zone through which droplets pass between the discharge nozzle and the surface, wherein the apparatus comprises at least one droplet deposited on the surface to diffuse the surface; Control means for controlling incorporation with at least one other droplet deposited on the substrate, and under the control of the control means, the droplet is deposited within the working zone for a predetermined time after the droplet is deposited. Locally exposed to radiation and stop the coalescence of the deposited droplets Wherein said exposure further comprises means for controlling the rate of solidification of said masking pattern by changing at least one liquid property of said deposition material. 93. The method of claim 90, wherein the time is 50 to 300 ms. 94. The method of claim 93, wherein the distance is 0.75 to 1.25 mm.

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