Methods and systems for forming vias

Abstract

A method of processing a substrate includes directing a pulsed laser beam through a window-substrate to form a focal spot within a liquid assist medium. A mount assembly includes the window-substrate and one or more spacers located at a surface of the window-substrate. A substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate. The liquid-assist medium is present within the gap and at a second surface of the substrate. The method includes moving the focal spot over a motion path through the second surface of the substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate. The via comprises more than one opening on the second surface of the substrate and / or on the first surface of the substrate.

Description

Attorney Docket No.: SP24-243 METHODS AND SYSTEMS FOR FORMING VIAS CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S.Provisional Application Serial No. 63 / 695933 filed on September 18, 2024, the content of which is relied upon and incorporated herein by reference in its entirety. FIELD

[0002] This disclosure relates to a method of processing a substrate, and more particularly tomethods of processing substrate utilizing a focused laser beam forming a focal spot within a liquid assist medium to create via(s) in the substrate. BACKGROUND

[0003] Precision machining of materials is used for many applications. Precisionmachining allows for the formation of miniature features in materials. Such features include holes, slots, grooves, and chamfers. Traditional techniques for precision machining involve mechanical methods (e.g., cutting, sawing, drilling, and scoring) or chemical methods (e.g., etching).

[0004] Adaptation of traditional techniques to more demanding applications,however, has proven to be challenging. There is increasing demand for machining finer features and for forming features in a wider variety of materials. There is currently great interest in the precision machining of hard dielectric materials and in forming high aspect ratio features with a high degree of precision. Computer numerical control (CNC) machining, for example, has challenges in drilling holes with a diameter smaller than 100- 200 microns in glass, especially when the aspect ratio exceeds 10-20.

[0005] Laser damage-and-etch processes have been used to form small features indielectric substrates, such as glass substrates. In this process, an ultrafast-laser is used to create damage tracks within the substrate. A subsequent etching process is used to “open up” the damage track to create the desired feature. However, this process requires two steps and is therefore slow. Further, the laser-damage-and-etch process typically results in “hourglass” shaped through-holes that deviate from a cylindrical profile.

[0006] Laser ablation has also been used to fabricate features within dielectricsubstrates. However, laser ablation results in rough feature walls, ablated debrisAttorney Docket No.: SP24-243 precipitation, chipping at the feature openings, as well as high residual laser-induced stress. Further, features cannot be fabricated in close proximity to one another due to the difference in the index of refraction between air and the substrate and the clipping of the laser beam due to the edge of an adjacent drilled feature.

[0007] Some approaches have included providing a liquid at the rear working surfaceof the substrate. However, these approaches have several disadvantages, such as spilled liquid that leaves nanoparticles on the front surface of the machined substrate, which are difficult to clean, and the drilled holes cannot be placed close to each other and to the edge of the substrate because of laser beam clipping.

[0008] Consequently, there exists an unresolved need for alternative systems andmethods for laser micromachining features into dielectric substrates. SUMMARY OF THE INVENTION

[0009] Various aspects of the present disclosure provide a method of processing asubstrate. The method includes directing a pulsed laser beam through a window-substrate, wherein a substrate attached to a mount assembly. The mount assembly includes the window-substrate and one or more spacers located at a surface of the window-substrate. A substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein a liquid-assist medium is present within the gap and at a second surface of the substrate. The pulsed laser beam forms a focal spot within the liquid assist medium. The method includes moving the focal spot over a motion path through the second surface of the substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally including a core therein. The method also optionally includes removing the optional core from the via. The via includes more than one opening on the second surface of the substrate and / or on the first surface of the substrate.

[0010] Various aspects of the present disclosure provide a method of processing asubstrate. The method includes directing a pulsed laser beam through a window-substrate. A mount assembly includes the window-substrate and one or more spacers located at a surface of the window-substrate. A substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein the liquid-assist medium is present within the gap and at a second surface of the substrate. The pulsed laser beam forms a focal spot within the liquid assist medium. The method includes moving the focal spot over a motion path through the second surface of theAttorney Docket No.: SP24-243 substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally including a core therein. The method includes maintaining an angle between an axis of the beam and the first and / or second surface of 80 degrees to 90 degrees throughout the moving of the focal spot over the motion path. The motion path of the beam includes an angle with respect to the axis of the beam of from equal to or greater than 0 degree to equal to or less than 90 degrees. The method also optionally includes removing the optional core portion from the via.

[0011] Various aspects of the present disclosure provide a method of processing asubstrate. The method includes directing a pulsed laser beam through a window-substrate. A mount assembly includes the window-substrate and one or more spacers located at a surface of the window-substrate. A substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein a liquid-assist medium is present within the gap and at a second surface of the substrate. The pulsed laser beam forms a focal spot within the liquid assist medium. The method includes moving the focal spot over a motion path through the second surface of the substrate and through a body of the substrate, to create a via in the substrate optionally including a core therein. The method also optionally includes removing the optional core portion from the via. The via includes at least one passage terminating in a blind hole, wherein the via is free of openings on surfaces of the substrate other than the second surface. The via includes more than one opening on the second surface of the substrate and / or more than one of the passages terminating in a blind hole.

[0012] Various aspects of the present disclosure provide a method of processing asubstrate. The method includes directing a pulsed laser beam through a window-substrate. A mount assembly includes the window-substrate and one or more spacers located at a surface of the window-substrate. A substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein a liquid-assist medium is present within the gap and at a second surface of the substrate. The pulsed laser beam forms a focal spot within the liquid assist medium. The method includes moving the focal spot over a motion path through the second surface of the substrate, through a body of the substrate, and through the second surface of the substrate, to create a via in the substrate optionally including a core therein. The method optionally includes removing the optional core portion from the via. The via includes more than one opening on the second surface of the substrate, and wherein the via is free of openings on surfaces of the substrate other than the second surface.Attorney Docket No.: SP24-243

[0013] Various aspects of the present disclosure provide a system for processing asubstrate. The system includes a laser system including a laser operable to produce a pulsed laser beam. The system also includes a mount assembly including a window-substrate and one or more spacers located at a surface of the window-substrate. The one or more spacers are configured to attach to a substrate such that a gap is present between a first surface of the substrate and the surface of the window-substrate. The system is configured such that a liquid-assist medium is disposable within the gap and at a second surface of the substrate. The system also includes an optical assembly operable to focus the pulsed laser beam through the window-substrate to a focal spot within the liquid medium and move the focal spot along a motion path through the second surface of a substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally including a core therein. After optional removal of the optional core from the via, the via includes more than one opening on the second surface of the substrate and / or on the first surface of the substrate.

[0014] Various aspects of the present disclosure provide a system for processing asubstrate. The system includes a laser system including a laser operable to produce a pulsed laser beam. The system includes a mount assembly including a window-substrate and one or more spacers located at a surface of the window-substrate. The one or more spacers are configured to attach to a substrate such that a gap is present between a first surface of the substrate and the surface of the window-substrate. The system is configured such that a liquid-assist medium is disposable within the gap and at a second surface of the substrate. The system also includes an optical assembly operable to focus the pulsed laser beam through the window-substrate to a focal spot within the liquid medium and move the focal spot along a motion path through the second surface of a substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally including a core therein. The system is configured to maintain an angle between an axis of the beam and the first and / or second surface of 80 degrees to 90 degrees throughout the moving of the focal spot over the motion path. The motion path of the beam includes an angle with respect to the axis of the beam of from greater than 0 degrees to equal to or less than 90 degrees.

[0015] Various aspects of the present disclosure provide a substrate including at leastone via including at least one opening on a second surface of the substrate and at least one opening on a first surface of the substrate. The via includes more than one of the openings on the second surface of the substrate and / or more than one of the openings on the first surface of the substrate.Attorney Docket No.: SP24-243

[0016] Various aspects of the present disclosure provide a substrate including at leastone via including at least one opening on a second surface of the substrate. The via includes at least one passage terminating in a blind hole. The via is free of openings on surfaces of the substrate other than the second surface. The via includes more than one opening on the second surface of the substrate and / or more than one of the passages terminating in a blind hole.

[0017] Various aspects of the present disclosure provide a substrate including at leastone via including more than one opening on the second surface of the substrate. The via is free of openings on surfaces of the substrate other than the second surface.

[0018] Various aspects of the presently disclosed method, system, and substrateincluding one or more vias can have various advantages. For example, in various aspects, the method can provide a via having more than one opening on the second surface of the substrate and / or the first surface of the substrate. In various aspects, the method can be used to form blind-vias or through-vias. In various aspects, the method can be used to form a via that includes more than one opening on the second surface and that is free of openings on other surfaces of the substrate. In some examples, the method can be performed while maintaining a substantially perpendicular angle between the first surface of the substrate and the axis of the beam, providing more efficient formation of vias than other methods. In various aspects, the method can be used to form vias having different cross-sectional profiles and / or side-profiles in the same substrate, avoiding a need to use a different apparatus to achieve different types of vias in the same substrate. In various aspects, the presently disclosed substrate including one or more vias that include more than one opening on the second surface of the substrate and / or the first surface of the substrate can have higher mechanical strength than the substrate without vias therein or than the substrate including other types of vias therein. In various aspects, the liquid-assist medium can be substantially free of acids. In various aspects, the method of the present disclosure can be used with thicker substrates than other methods, such as substrates having a thickness of 1.1 mm or greater, or 2 mm or greater, or 3 mm or greater.

[0019] In various aspects, compared to etching or laser-etch methods, the system andmethod of the present invention creates less or no hazardous byproducts requiring costly treatment and / or recycling. In various aspects, compared in “dry” ablation in air, the system and method of the present invention provides vias in a substrate with low surface defects and low residual stress, therefore providing higher substrate strength.Attorney Docket No.: SP24-243 BRIEF DESCRIPTION OF THE FIGURES

[0020] The drawings illustrate generally, by way of example, but not by way oflimitation, various aspects of the present invention.

[0021] FIG. 1A is a schematic elevated view of an example liquid-assisted laser-based micromachining system for processing a substrate according to various aspects of the present disclosure.

[0022] FIG. 1B is a side view of the liquid-assist laser-based micromachining systemof FIG.1A.

[0023] FIG. 2A is a perspective view of the cuvette of the liquid-assist laser-basedmicromachining system of FIGS.1A and 1B according to various aspects of the present disclosure.

[0024] FIG. 2B is a close-up view of the substrate and the cuvette showing an initialfocus position of the focal spot within the liquid-assist medium and adjacent the interface between the liquid-assist medium and the back (working) surface of the substrate according to various aspects of the present disclosure.

[0025] FIG. 2C schematically depicts a helical path of a focal spot produced by afocused laser beam according to various aspects of the present disclosure.

[0026] FIG. 2D shows the motion path of the focal spot used to form a helicalmodification to the material that constitutes the body of the substrate as part of the process of forming a feature in the substrate according to various aspects of the present disclosure.

[0027] FIG. 2E is similar to FIG. 2D and shows the final helical modification and theresulting core portion defined by the final helical modification, with the close-up inset showing example micromachined regions that constitute the modification according to various aspects of the present disclosure.

[0028] FIG. 3 is a top perspective view of an article having laser micromachinedfeatures according to various aspects of the present disclosure.

[0029] FIG. 4A is a microscope photograph of through-holes fabricated withouthaving a liquid-assist medium at a front surface of the substrate according to various aspects of the present disclosure.

[0030] FIG. 4B is a microscope photograph of through-holes fabricated with having aliquid-assist medium at both the front surface and the rear surface of the substrate according to various aspects of the present disclosure.

[0031] FIG. 5 is a perspective view of a substrate having a through-hole and a dicingplane for evaluating wall quality to according to various aspects of the present disclosure.Attorney Docket No.: SP24-243

[0032] FIG. 6A schematically illustrates the fabrication of a feature adjacent to apreviously drilled feature according to various aspects of the present disclosure.

[0033] FIG. 6B is a microscope photograph of through-holes fabricated close to anedge of a substrate according to various aspects of the present disclosure.

[0034] FIG. 7A schematically depicts various features fabricated at an edge of asubstrate according to various aspects of the present disclosure.

[0035] FIG. 7B illustrates a photograph of a feature formed on an edge of a substrateaccording to various aspects of the present disclosure.

[0036] FIG. 8A illustrates an isometric view of an array of 60-micron and 115-micronthrough-vias in a 1.1 mm thick IRIS glass substrate according to various aspects of thepresent disclosure.

[0037] FIG. 8B illustrates a top view of the array shown in FIG. 8B according tovarious aspects of the present disclosure.

[0038] FIG. 9A illustrates an isometric via of an array of V-shaped vias in 1.1 mmthick IRIS glass substrate according to various aspects of the present disclosure.

[0039] FIG. 9B illustrates a top view of the array of vias shown in FIG. 9A accordingto various aspects of the present disclosure.

[0040] FIG. 10A illustrates an isometric view of an array of Y-shaped vias accordingto various aspects of the present disclosure.

[0041] FIG. 10B illustrates front, side, and back views of the array of vias shown inFIG. 10A according to various aspects of the present disclosure.

[0042] FIG. 11A illustrates a side profile of a via in a substrate formed using a helicalmotion path of the focal spot to drill a circumferential outline around the core, according tovarious aspects of the present disclosure.

[0043] FIG. 11B illustrates a side profile of a via in a substrate formed with completeablation of the interior of the via, according to various aspects of the present disclosure.DETAILED DESCRIPTION OF THE INVENTION

[0044] Reference will now be made in detail to certain aspects of the disclosedsubject matter. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter.

[0045] Throughout this document, values expressed in a range format should beinterpreted in a flexible manner to include not only the numerical values explicitly recited asAttorney Docket No.: SP24-243 the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “about 0.1% to about 5%” or “about 0.1% to 5%” should be interpreted to include not just about 0.1% to about 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “about X to Y” has the same meaning as “about X to about Y,” unless indicated otherwise. Likewise, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z,” unless indicated otherwise.

[0046] In this document, the terms “a,” “an,” or “the” are used to include one or morethan one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B” or “at least one of A or B” has the same meaning as “A, B, or A and B.” In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.

[0047] In the methods described herein, the acts can be carried out in a specific orderas recited herein. Alternatively, in any aspect(s) disclosed herein, specific acts may be carried out in any order without departing from the principles of the invention, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately or the plain meaning of the claims would require it. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0048] The term “about” as used herein can allow for a degree of variability in avalue or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range, and includes the exact stated value or range.

[0049] The term “substantially” as used herein refers to a majority of, or mostly, as inat least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%. The term “substantially free of” as used herein can mean having none or having a trivial amount of, such that the amount of material present does not affect the material properties of the composition including the material, such that about 0 wt% to about 5 wt% of the composition is the material, or about 0 wt% to about 1 wt%, or about 5 wt% or less, or less than, equal to, or greater than about 4.5Attorney Docket No.: SP24-243 wt%, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01, or about 0.001 wt% or less, or about 0 wt%.

[0050] As used herein, contact refers to direct contact or indirect contact. Directcontact refers to contact in the absence of an intervening material and indirect contact refers to contact through one or more intervening materials. Elements in direct contact touch each other. Elements in indirect contact do not touch each other, but are otherwise joined to each other through one or more intervening elements. Elements in contact may be rigidly or non- rigidly joined. Contacting refers to placing two elements in direct or indirect contact. Elements in direct (indirect) contact may be said to directly (indirectly) contact each other.

[0051] As used herein, a material is “transparent” to a wavelength of light if theinternal transmission of light at the wavelength is greater than 80%. Preferably, the internal transmission is greater than 90%, or greater than 95%. As used herein, internal transmission refers to transmission exclusive of reflection losses.

[0052] As used herein, “working surface” refers to a surface of a substrate in contactwith a liquid-assist medium in a liquid-assisted laser micromachining process.

[0053] As used herein, an “optical fiber component” is any element or assembly thatis used to operably support at least one optical fiber. Example optical fiber components include optical fiber guide members, optical fiber support members and optical fiber interconnection devices.

[0054] As used herein, a “via” is a passage in a substrate including at least oneopening on a surface of the substrate. A via can be a through-passage that passes through the substrate and includes at least two openings (e.g., a through-via) or a blind-passage that includes one end with an opening on one side of the substrate and another end that terminates within the substrate without an opening on a side of the substrate.

[0055] Cartesian coordinates are used in some of the Figures for reference and ease ofexplanation and are not intended to be limiting as to direction and / or orientation. Method of processing a substrate.

[0056] Various aspects of the present disclosure provide a method of processing asubstrate. The method can include directing a pulsed laser beam through a window-substrate and through a substrate to form a focal spot within a liquid assist medium. The substrate is attached to a mount assembly. The mount assembly includes the window-substrate and one or more spacers located at a surface of the window-substrate. The substrate can be attached to the one or more spacers (e.g., attached to the first surface of the substrate) such that a gapAttorney Docket No.: SP24-243 is present between a first surface of the substrate and the surface of the window-substrate. The liquid-assist medium can be present within the gap and at a second surface of the substrate, such that the liquid-assist medium is present at the second surface of the substrate and the first surface of the substrate. The method can include moving the focal spot over a motion path through the second surface of the substrate, through a body of the substrate, and through the first surface of the substrate. The via formed can be free of a core therein; for example, the laser can completely ablate the interior of the via such that the via is formed with no need to remove a core portion thereof. The via formed can optionally include a core therein; for example, the laser can drill a circumferential outline of the via leaving a core in the via which can be removed, such as by using a helical motion path of the focal spot. In aspects of the method that form a via having a core therein, the method can also include removing the core portion from the via.

[0057] The via can include more than one opening on the second surface of thesubstrate and / or on the first surface of the substrate. The first and second surface of the substrate are located on different sides of the substrate. The via can have at least two openings. The via can include 0, 1, 2, 3, 4, 5 or more openings on the second surface of the substrate and 0, 1, 2, 3, 4, or 5 or more openings on the first surface of the substrate. The second surface of the substrate can be a back or side of the substrate, and the first surface of the substrate can be a front of the substrate. The second surface of the substrate can be a back of the substrate, and the first surface of the substrate can be a front of the substrate. The second surface of the substrate can be a side of the substrate, and the first surface of the substrate can be a front surface of the substrate. The via can include one or more openings on a side surface of the substrate and be free of openings on a front and / or back of the substrate. The via can include one or more openings on a back of the substrate and be free of openings on a side surface of the substrate. In various aspects, the via can be free of portions that intersect a side surface or edge of the substrate. In various aspects, at least one portion of the via can intersect a side surface or edge of the substrate.

[0058] The via can include any suitable number of openings on the first and secondsurface of the substrate. The via can include a different number of openings on the first surface of the substrate than the second surface of the substrate. The via can include two openings on one end of the via and one opening on an opposite end of the via (e.g., a via having a Y-shaped or V-shaped side profile). The via can include two openings on one end of the via and two openings on an opposite end of the via (e.g., a via having an X-shaped side profile). The via can include three openings on one end of the via and one opening on anAttorney Docket No.: SP24-243 opposite end of the via. A side-profile of the via can have a Y-shape, a V-shape, or an X- shape. The via can be a bifurcated via. The via can be a trifurcated via. The via can include a hollowed-out chamber (e.g., mixing chamber) between two narrower portions of the via.

[0059] The cross-sectional profile of the via (e.g., perpendicular to a longitudinaldirection of the via) can have any suitable shape. For example, the cross-sectional profile of the via can be circular, elliptical, round, square, rectangular, polygonal, or a combination thereof. The cross-sectional profile can vary along its length or be consistent along its length. The cross-sectional profile of the via can be circular with a consistent diameter such that the via is a cylindrical via. In various aspects, a cross-sectional profile of the via can deviate from a predefined cross-sectional profile by an amount that is less than or equal to 5 microns, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, or less than or equal to 0.5 microns.

[0060] The via can have a maximum cross-sectional size (e.g., diameter) of 15microns to 500 microns, or 15 microns to 250 microns, or 15 microns to 100 microns, or less than or equal to 500 microns and greater than or equal to 15 microns and less than, equal to, or greater than 20 microns, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 120, 140, 160, 180, 200, 250, 300, 350, 400, or 450 microns. The via can have a ratio of a maximum cross-sectional size of the via (e.g., diameter) to a length of the via of 1:10 or less, or 1:25 or less, or 1:50 or less. The via can have a ratio of a maximum cross-sectional size of the via to a thickness of the substrate in a location of the via of 1:10 or less, or 1:25 or less, or 1:50 or less.

[0061] The motion path of the focal spot can have any suitable shape within thesubstrate. For example, the motion path can have or include the shape of a straight line. The motion path can have or include a helical shape. The motion path can have or include the shape or a curved line. The motion path can have a Y-shape, a V-shape, or an X-shape.

[0062] In various aspects, the mount assembly can be attached to an opening of acuvette. The liquid-assist medium can be provided within the cuvette.

[0063] The gap between the first surface of the substrate and the surface of thewindow-substrate can have any suitable thickness, such as a thickness of 0.06 mm to 1.6 mm, or less than or equal to 1.6 mm and greater than or equal to 0.06 mm and less than, equal to, or greater than 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, or 1.55 mm.

[0064] The substrate can have a transmittance (e.g., an internal transmittance) of morethan 50% at a wavelength of the pulsed laser beam, or of greater than or equal to 80% at a wavelength of the pulsed laser beam, or less than or equal to 100% and greater than or equalAttorney Docket No.: SP24-243 to 50% and less than, equal to, or greater than 55%, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 92, 94, 96, or 98%.

[0065] The substrate can be a dielectric substrate. The substrate can include glass,glass-ceramic, a crystalline material, a transparent dielectric material, or a polymer material. The substrate can be a glass substrate.

[0066] The substrate can have any suitable shape. In various aspects, the substratecan be a planar substrate. The substrate can have any suitable thickness, such as a thickness of 50 microns to 10 mm, or less than or equal to 10 mm and greater than or equal to 50 microns and less than, equal to, or greater than 100 microns, 200, 300, 400, 500, 600, 700, 800, 900 microns, 1 mm, 1.2, 1.4, 1.6, 1.8, 2, 2.5, 3, 4, 5, 6, 7, 8, or 9 mm. The substrate can have a thickness of less than or equal to 2 mm, or less than or equal to 1.2 mm.

[0067] Providing the liquid-assist medium at the first and second surface of thesubstrate can reduce surface contamination with process byproducts, reduce front surface chipping by reducing acoustic shock at the front surface, enable a smaller distance between vias, provide the ability to place holes via to the edge of the substrate, provide the ability to create precision features on the edge of the substrate, or a combination thereof. The liquid- assist medium can include water, an organic solvent, or a combination thereof. The liquid- assist medium can be selected from one or more of water, water with added surfactants, a fluorinated alkane, a fluorinated alcohol, a fluorinated amine, methanol, ethanol, acetone, dimethyl sulfoxide, ethylene glycol, and a perfluorinated compound. The liquid-assist medium can be substantially free of acid; for example, the liquid-assist medium can be 0 wt% acid, or 0 wt% to 0.1 wt% acid, or 0 wt% to 0.01 wt% acid, or 0 wt% to 0.001 wt% acid. The liquid-assist medium can be substantially free of base; for example, the liquid-assist medium can be 0 wt% base, or 0 wt% to 0.1 wt% base, or 0 wt% to 0.01 wt% base, or 0 wt% to 0.001 wt% base.

[0068] The liquid-assist medium can have a boiling point greater than or equal to 80°C, or 80 °C to 300 °C, or less than or equal to 300 °C and greater than or equal to 80 °C and less than, equal to, or greater than 90 °C, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 220, 240, 260, or 280 °C. A difference in a refractive index of the liquid-assist medium and a refractive index of the substrate can be less than 0.3, or 0 to 0.3, or less than or equal to 0.3 and greater than or equal to 0 and less than, equal to, or greater than 0.05, 0.1, 0.15, 0.2, or 0.25. The liquid-assist medium can have a surface tension of less than or equal to 72 dynes / cm at 25 °C, or less than or equal to 50 dynes / cm at 25 °C, or 10 to 72 dynes / cm at 25 °C, or 20 to 72 dynes / cm at 25 °C, or less than or equal to 72 dynes / cm at 25 °C and greaterAttorney Docket No.: SP24-243 than or equal to 10 dynes / cm at 25 °C and less than, equal to, or greater than 20 dynes / cm at 25 °C, 30, 40, 50, 55, 60, 65, or 70 dynes / cm at 25 °C. The liquid-assist medium can have an internal transmittance of greater than or equal to 70% per mm, or 70% per mm to 100% per mm, or less than or equal to 100% per mm and greater than or equal to 70% per mm and less than, equal to, or greater than 72% per mm, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, or 99% per mm.

[0069] The focal spot can have a circular profile. The focal spot can have a non-circular profile, such as elliptical, round, square, rectangular, or polygonal.

[0070] The motion path of the beam can be parallel to an axis of the beam, such aswithin about 0° of the axis of the beam, or within 0° to 5°, or within 0° to 3°, or within 0° to 1°, or within less than or equal to 5° and greater than or equal to 0° and less than, equal to, or greater than 0.5°, 1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5°. The motion path of the beam can be non- parallel to an axis of the beam, such as within greater than 0° to less than or equal to 90° of the axis of the beam, or 5° to 90°, or 10° to 90°, or within less than or equal to 90° and greater than 0° and less than, equal to, or greater than 1°, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85°. The method can include maintaining any suitable angle between the axis of the beam and the first and / or second surface of the substrate as the focal spot moves along the motion path of the beam, such as an angle of 40° to 90°, 50° to 90°, or 60° to 90°, or 80° to 90°, or 85° to 90°, or greater than or equal to 40° and less than or equal to 90° and less than, equal to, or greater than 45°, 50, 55, 60, 65, 70, 72, 74, 76, 78, 80, 81, 82, 83, 84, 85, 86, 87, 88, or 89°. The method can include maintaining the beam substantially perpendicular to the first and / or second surface of the substrate during the moving the focal spot over the motion path. By maintaining the beam within 80° to 90° or substantially perpendicular to the first and / or second surface during the moving of the focal spot over the motion path, the method can make more efficient use of laser power as compared to methods having a less perpendicular angle between the axis of the beam and the first and / or second surface.

[0071] In various aspects, the method includes forming one and not more than one ofthe vias. In other aspects, the method includes forming two or more of the vias. The method can include performing the directing, moving, and removing two or more times to form two or more of the vias. The method can include forming the two or more vias in series. The method can include forming the two or more vias at least partially simultaneously (e.g., including splitting the laser beam into multiple beams for parallel processing). The two or more vias can form an array of the vias in the substrate. The two or more vias can haveAttorney Docket No.: SP24-243 substantially the same side-profile and / or cross-sectional profile, or the two or more vias can have a different side-profile and / or cross-sectional profile. The two or more vias can have the same number of openings on the first and second surface of the substrate, or the two or more vias can have a different number of openings on the first and / or second surface of the substrate. The two or more vias can have any suitable spacing therebetween. In some aspects, the two or more vias can include a distance between at least a portion of the two or more vias of less than or equal to 20 microns, or 1 micron to 20 microns, or less than or equal to 20 microns and greater than or equal to 1 micron and less than, equal to, or greater than 2 microns, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 microns. In some aspects, the two or more vias can contact, merge, or overlap with one another, such as at the first and / or second surface of the substrate, within the substrate, or a combination thereof.

[0072] In various aspects, the method includes attaching a substrate to a mountassembly. The mount assembly can include a window-substrate and one or more spacers located at an inner surface of the window-substrate. The mount assembly can further include a cover having an opening, and the window-substrate can be hermetically attached to an inner surface of the cover at the opening. The substrate can be releasably attached to the one or more spacers such that the substrate may be removed from the mount assembly after laser processing. The material of the one or more spacers can be chosen such that the substrate is maintained on the mount assembly during laser processing.

[0073] The mount assembly can be attached to an open end of a cuvette. The mountassembly can be attached by fasteners. In some aspects, a gasket can be provided to hermetically seal the cover to the body of the cuvette.

[0074] A liquid-assist medium can then be provided to the interior of the cuvette,such that the liquid-assist medium is present within the gap between the window-substrate and the substrate created by the one or more spacers. Thus, the liquid-assist medium can contact both the first surface (e.g., front surface) and the second surface (e.g., back surface or side surface) of the substrate.

[0075] A pulsed laser beam can then be directed through the window-substrate, theliquid-assist medium within the gap, and the substrate to form a focal spot having an initial position in the liquid-assist medium behind the second surface of the substrate. The focal spot can then be moved over the motion path of the beam to create a modification of a material of the substrate that defines a via in the body of the substrate.

[0076] In aspects of the method that form the via including a core therein, aftercompletion of the motion path, the core portion of the body can be removed to form the via.Attorney Docket No.: SP24-243 Any known or yet-to-be-developed method of removing the core may be used. As a non- limiting example, ultrasonic energy may be applied to the substrate to cause the core to drop out of the body.

[0077] In various aspects, the present disclosure provides a method of processing asubstrate. The method can include directing a pulsed laser beam through a window-substrate. A mount assembly includes the window-substrate and one or more spacers located at a surface of the window-substrate. The substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window- substrate, and wherein the liquid-assist medium is present within the gap and at a second surface of the substrate. The pulsed laser beam forms a focal spot within the liquid assist medium. The method can include moving the focal spot over a motion path through the second surface of the substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally including a core therein. The method can include maintaining an angle between an axis of the beam and the first and / or second surface of 80 degrees to 90 degrees throughout the moving of the focal spot over the motion path. The motion path of the beam can include an angle with respect to the axis of the beam of from equal to or greater than 0 degree to equal to or less than 90 degrees. The method can also optionally include removing the optional core from the via.

[0078] Various aspects of the present disclosure provide a method of processing asubstrate to form a blind-via. The method can include directing a pulsed laser beam through a window-substrate. A mount assembly includes the window-substrate and one or more spacers located at a surface of the window-substrate. A substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein a liquid-assist medium is present within the gap and at a second surface of the substrate. The pulsed laser beam forms a focal spot within the liquid assist medium. The method can include moving the focal spot over a motion path through the second surface of the substrate and through a body of the substrate, to create a via in the substrate optionally including a core therein. The method can also optionally include removing the core from the via. The via includes at least one passage terminating in a blind hole. The via can be free of openings on surfaces of the substrate other than the second surface. The via can include more than one opening on the second surface of the substrate and / or more than one of the passages terminating in a blind hole.

[0079] Various aspects of the present disclosure provide a method of processing asubstrate for forming a via with more than one opening on the second surface of the substrateAttorney Docket No.: SP24-243 and that is free of openings on other surfaces of the substrate. The method can include directing a pulsed laser beam through a window-substrate. A mount assembly includes the window-substrate and one or more spacers located at a surface of the window-substrate. The substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein a liquid-assist medium is present within the gap and at a second surface of the substrate. The pulsed laser beam forms a focal spot within the liquid assist medium. The method can include moving the focal spot over a motion path through the second surface of the substrate, through a body of the substrate, and through the second surface of the substrate, to create a via in the substrate optionally including a core therein. The method can optionally include removing the optional core from the via. The via can include more than one opening on the second surface of the substrate. The via can be free of openings on surfaces of the substrate other than the second surface. System for processing a substrate.

[0080] Various aspects of the present disclosure provide a system for processing asubstrate. The system can be any suitable system that can perform one or more aspects of the method for processing a substrate described herein.

[0081] The system can include a laser system including a laser operable to produce apulsed laser beam. The system can include a mount assembly including a window-substrate and one or more spacers located at a surface of the window-substrate. The one or more spacers can be configured to attach to a substrate such that a gap is present between a first surface of the substrate and the surface of the window-substrate. The system can be configured such that a liquid-assist medium is disposable within the gap and at a second surface of the substrate. The system can include independent flow control of the liquid within the gap and at the second surface of the substrate, or flow control of the liquid within the gap and at the second surface of the substrate can be combined. The liquid-assist medium can be pumpable and flowable. The system can include an optical assembly operable to focus the pulsed laser beam through the window-substrate to a focal spot within the liquid medium and move the focal spot along a motion path through the second surface of a substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally including a core therein. The via includes more than one opening on the first surface of the substrate and / or on the second surface of the substrate.Attorney Docket No.: SP24-243 In aspects of the system that form the via including the optional core in the via, the system can be configured to remove the core from the via.

[0082] The system can include a laser system including a laser operable to produce apulsed laser beam. The system can include a mount assembly including a window-substrate and one or more spacers located at a surface of the window-substrate. The one or more spacers can be configured to attach to a substrate such that a gap is present between a first surface of the substrate and the surface of the window-substrate. The system can be configured such that a liquid-assist medium is disposable within the gap and at a second surface of the substrate. The system can include an optical assembly operable to focus the pulsed laser beam through the window-substrate to a focal spot within the liquid medium and move the focal spot along a motion path through the second surface of a substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally including a core therein. The system can be configured to maintain an angle between an axis of the beam and the first and / or second surface of 80 degrees to 90 degrees throughout the moving of the focal spot over the motion path. The motion path of the beam can include an angle with respect to the axis of the beam of from greater than 0 degrees to equal to or less than 90 degrees.

[0083] FIG. 1A is a schematic elevated view of an example liquid-assisted laser-based micromachining system (“system”) 10 for processing a transparent dielectric to form an substrate having one or more vias therein. FIG.1B is a schematic side view of the system of FIG.1A. The system 10 includes a laser source 20, which produces a substantially collimated laser beam 22 that passes in a direction of propagation along a system axis AZ that runs in the z-direction. In an example, the laser source 20 can include beam collimating optics (not shown) to form the substantially collimated laser beam 22.

[0084] The wavelength of the laser source 20 can be any wavelength at which thedielectric material of the substrate 100 is transparent. Typical laser wavelengths for common substrates are in the UV, visible, or near-infrared portions of the electromagnetic spectrum. Representative laser wavelengths include wavelengths in the range from 325 nm to 1700 nm, or in the range from 400 nm to 1500 nm, or in the range from 500 nm to 1250 nm, or in the range from 700 nm to 1100 nm. The material of the substrate can have an internal transmittance at the laser wavelength of greater than 50%, greater than 60%, greater than 70%, greater than 80%, greater than 90%, greater than 95%, or 100%.

[0085] The laser source 20 is operable to produce a pulsed laser beam 22. As shownin FIG. 1B, the laser beam 22 includes a train of laser pulses 22P. The duration of the laserAttorney Docket No.: SP24-243 pulses 22P can vary over a range extending from the femtosecond (fs) regime to the picosecond (ps) regime. Representative pulse durations are in the range from 10 fs to 100 ps, or in the range from 50 fs to 50 ps, or in the range from 500 fs to 50 ps, or in the range from 1 ps to 100 ps, or in the range from 1 ps to 10 ps. In some aspects, shorter laser pulses 22P are preferable to longer laser pulses.

[0086] In another example, the laser beam parameters include: a pulse length for thelaser pulses 22P in the range from 1 to 50 ps; a laser pulse energy in the range from 1 microjoules to 100 microjoules; a repetition rate in the range from 1 kHz to 1 MHz or in the range from 1 kHz to 500 kHz; a focal spot size FS (defined below) in the range from 2 microns to 10 microns; a wavelength in the range from 0.3 microns to 2 microns; and a laser beam (and / or cuvette) translation speed in the range from 0.001 mm / s to 10 mm / s in the AZ axis direction.

[0087] The system 10 can also include a focusing optical system 40 downstream ofthe laser source 20 and along the system axis AZ. The focusing optical system 40 can include one or more optical elements such as one or more focusing lenses or focusing optics. In an example, the focusing optical system 40 can also include one or more elements that provide beam conditioning (e.g., spatial filtering, wavelength filtering, and the like) and can also include one or more elements for beam steering (e.g., rotatable mirrors, and the like). The focusing optical system 40 has a focal length FL, a numerical aperture NA and clear aperture CA.

[0088] The system 10 also includes a cuvette 50 having an interior 56 configured tocontain a liquid-assist medium 60. FIG. 1A illustrates an assembled cuvette 50, while FIG. 1B illustrates a cross-section of the cuvette 50 illustrating the interior 56 and interior components, which are described herein.

[0089] One example liquid-assist medium includes water or consists essentially ofwater. Other example liquid-assist media are described herein. In an example, the cuvette is substantially stationary and the laser source is mobile. In another example, the cuvette is mobile and the laser source is substantially stationary. In another example, both the cuvette and the laser source are mobile. In an example, the cuvette 50 can be operably supported by a movable precision x-y-z stage 30 that can move the cuvette in the x, y and z directions. In an example, the system 10 only includes the movable precision stage 30 and the laser source is substantially stationary (e.g., is movable for coarse alignment). In an example, the laser source 20, the focusing optical system 40 and the cuvette 50 are operably supported by a support base 70, such as an optical bench or like stable platform. In an example shown inAttorney Docket No.: SP24-243 FIG. 1B, a computer controller 80 is operably connected to the movable precision x-y-z stage 30 and the optional movable stage 44 to control the movement of one or both of the movable precision stages in operating the system 10 to carry out the micromachining methods described herein. The cuvette 50 can have an open side 54.

[0090] The system 10 can be configured to process a substrate 100 having a body 101that defines a first surface 102 and a second surface 104 (shown as a back surface in this aspect). The substrate 100 can include a dielectric material, and in examples includes glass, glass-ceramic, a crystalline material, a transparent dielectric material, or a polymer material. In an example, the substrate includes sapphire. Example glasses include oxide glasses and non-oxide glasses. Preferred glasses are silica glasses, including alkali silica glasses, alkaline earth silica glasses, and borosilicate glasses. Glasses include glasses strengthened by ion exchange or thermal tempering. Example crystals include oxide crystals, such as metal oxides, and non-oxide crystals. Example glasses can include soda-lime glasses, alkaline earth boro-aluminosilicate, alkali-aluminosilicate glass, and Corning Iris™ glass.

[0091] In an example, the substrate 100 is rectangular and substantially planar withsubstantially parallel first and second surfaces 102 and 104 and a substantially constant thickness TH2. Other shapes for the substrate 100 can also be employed, and the rectangular and planar substrate is shown by way of example and for ease of illustration and explanation. In an example, the thickness TH2 of the substrate 100 in the z- direction is at least 0.09 mm or at least 0.2 mm or at least 0.5 mm (FIG.2B).

[0092] FIG. 2A is a front perspective view of an assembled cuvette 50. The examplecuvette 50 generally includes a cuvette body 51 and a cover 53 that is attached to an open side of the cuvette body 51 by any means such as, without limitation, fasteners 59. The cover 53 includes an opening 55, and a transparent window-substrate 31 mounted on an interior surface of the cover 53 that seals the opening 55. The window-substrate 31 is transparent to the wavelength of the laser beam 22. For example, the window-substrate has an internal transmittance at the laser beam wavelength of more than 50% at a wavelength of the pulsed laser beam, or of greater than or equal to 80% at a wavelength of the pulsed laser beam, or less than or equal to 100% and greater than or equal to 50% and less than, equal to, or greater than 55%, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 92, 94, 96, or 98%.

[0093] Two spacers 32 can be attached to a surface of the window-substrate 31 thatfaces the interior 56 of the cuvette 50. The spacers 32 (which may include one or more spacers) are operable to provide a gap G between the window-substrate 31 and a working substrate 100. The material of the spacers 32 is such that the substrate 100 is releaseablyAttorney Docket No.: SP24-243 attached to the spacers 32. Any suitable material can be used for the spacers. As a non- limiting example, plastic shims or stainless steel shims may be used for the spacers 32. The cover 53, window-substrate 31, and spacers 32 define a mount assembly 35.

[0094] As shown in FIGS. 1B and 2B, the substrate 100 is maintained within theinterior 56 of the cuvette in a vertical orientation. In aspects of the present disclosure, the substrate 100 can be maintained within ten degrees of a vertical orientation (e.g., with a longitudinal axis of the substrate within ten degrees of a vertical orientation). This vertical or nearly vertical orientation provides for air bubbles to quickly rise due to liquid convection and not become trapped and occlude the focused laser beam 22F. Additionally, the vertical or nearly vertical orientation allows debris from the laser process to drop away from the substrate so that it too does not occlude the focused laser beam 22F.

[0095] The example cuvette 50 can further include one or more openings (not shown)for providing liquid to the interior 56, and one or more liquid outlets 58 for draining liquid from the interior 56 of the cuvette 50 upon completion of processing.

[0096] Water is one example of a liquid-assist media 60 for liquid-assisted lasermicromachining and high ablation rates. When water is used, a surfactant can be added to reduce surface tension and to prevent byproduct accumulation on the surface of the substrate 100 and to reduce the acoustic shock effect. As a non-limiting example, sodium dodecyl sulfate may be used as a surfactant. Other common surfactants may also be utilized.

[0097] Other example liquid-assist media 60 include 3M Fluorinert (e.g., FC-70) andNovec engineering liquids (e.g.7500, 7700), solvents (e.g., methanol, ethanol, acetone, DMSO (dimethylsulfoxide)), ethylene glycol, and other liquids. Preferable attributes are low viscosity, high boiling point (e.g., greater than or equal to 80° C), high specific heat, low surface tension (for improved precision, e.g., a surface tension of less than or equal to 50 dynes / cm at 25° C, or less than or equal to 72 dynes / cm at 25° C) and high surface tension for high material removal rate (e.g., a surface tension of more than 50 dynes / cm at 25° C, or more than 72 dynes / cm at 25° C). Further, the difference between the refractive index of the substrate 100 and the refractive index of the liquid-assist media 60 can be small, such as, without limitation, less than or equal to less than 0.3, or 0 to 0.3, or less than or equal to 0.3 and greater than or equal to 0 and less than, equal to, or greater than 0.05, 0.1, 0.15, 0.2, or 0.25. For instance, DMSO has a refractive index of about 1.48, which differs from the typical glass refractive index of 1.45 by 0.03. Beam clipping and distortion effects are further reduced.Attorney Docket No.: SP24-243

[0098] FIG. 2B illustrates a close-up cross-sectional view of the cuvette 50 illustratedby FIGS.1A and 1B without the cover 53. Unlike previous systems, the spacers 32 are operable to provide a gap G between an inner surface of the window-substrate 31 and the first surface 102 of the substrate 100. The gap G should not be too small such that convection is insufficient and air bubbles become stuck between the window-substrate 31 and on the substrate 100. On the other hand, too thick of a gap G may cause laser beam distortion and poor focusing because of turbulent convection. The minimum and maximum thickness of the gap G may be different for different liquids. As a non-limiting example, the gap G can have a thickness within a range of 0.06 mm and 1.6 mm, including endpoints, when the liquid- assist medium 60 is water.

[0099] The substrate 100 can be disposed in system 10 so that the second surface 104is in direct contact with the liquid-assist medium 60 of the cuvette 50. Because of the gap G, the first surface 102 of the substrate 100 is also in direct contact with the liquid-assist medium 60. In an example, the substrate 100 is also supported by the movable precision x-y- z stage 30 so that the substrate and cuvette 50 move together.

[0100] In the operation of the system 10 to carry out the micromachining methodsdisclosed herein, the substrate 100 is moved into a desired position relative to the system axis AZ using the movable precision x-y-z stage 30. Once in position, the laser source 20 is activated to form the substantially collimated beam 22, which is received by the focusing optical system 40. The focusing optical system 40 forms from the substantially collimated beam 22 a focused laser beam 22F that is focused to a focal spot FS at a focus position FP along the system axis AZ. The focal spot FS has a diameter defined by a Gaussian beam waist, which in an example can be in the range from 1 microns to 5 microns. The focal spot FS also has an associated Rayleigh length, which in an example is in the range from 1.6 microns to 20 microns. An exemplary focal spot diameter can be 2 microns and an exemplary Rayleigh length can be 6.5 microns for applications where the substrate 100 has the form of a thin sheet of glass.

[0101] In an example, the focused laser beam 22F passes through the window-substrate 31, the gap G, and the substrate 100 and forms the focal spot FS within the liquid- assist medium 60. FIGS.1B and 2B show an initial focus position FP of the focal spot FS within the liquid-assist medium 60 and adjacent an interface 110 defined by the second surface 104 (hereinafter, working surface 104) and the liquid-assist medium 60, e.g., in the liquid-assist medium within about 10 microns of the interface. FIG. 2D is a close-up view of the irradiated portion of the substrate 100 showing the completed formation of the example ofAttorney Docket No.: SP24-243 a helical modification 121 formed in the body 101 of the substrate 100 by ablation by the focal spot FS moving over the example helical motion path MP of FIG.2B.

[0102] The focal spot FS can be subsequently moved forward to be at or near theinterface 110. The focal spot FS has sufficient intensity to alter the structure of the material that makes up the body 101 of the substrate to define a modification 121 to the material that structurally weakens the material as shown in FIG.2D.

[0103] Next, the laser source 20 and / or the substrate 100 and cuvette 50 can betranslated in the x, y and / or z directions to control the position of the focal spot FS and the shape of the feature 150 formed in the body of the substrate 100. The movable stage 44 of the focusing optical system 40 can be used to steer the focused laser beam 22F. FIG.2C shows an example motion path MP and modification 121 in the process of being formed by moving the focal spot FS along a helical motion path MP that includes a z-component as indicated by the arrow. In an example, the helical motion path MP can have a pitch in the range from 0.1 microns to 30 microns.

[0104] The lateral dimensions of the modification 121 can be controlled throughmotion of the focal spot FS over the motion path MP in the x and y directions and the depth of the feature can be controlled by movement of the focal spot over the motion path in the z direction. The dimensions of the modification 121 can also be controlled by varying the position of the focal spot FS of focused laser beam 22F. The modification 121 is ultimately used to form at least one feature in the substrate 100, as explained herein.

[0105] Thus, in an example, the formation of the modification 121 begins at theworking surface 104 and continues through the body 101 in the direction of the front surface 102.

[0106] In one aspect, formation of the modification 121 includes ablation of thematerial that makes up the body 101 of the substrate 100. As material is removed from the working surface 104, the liquid-assist medium 60 from the cuvette 50 flows to occupy the evacuated space to maintain a wetted surface for heat removal and further micromachining. Micromachining at different depths relative to the working surface 104 can be achieved by moving the focal spot FS of the focused laser beam 22F (either through variation in the focusing optical system 40 or relative motion of the laser and working surface) in the direction from the working surface 104 toward the first surface 102 of the substrate 100 over a select motion path MP. The modifications 121 can be formed in the body 101 of the substrate 100 having depths varying from a partial thickness TH2 of the substrate to the full thickness of the substrate. In an example, the size (diameter) of the focal spot FS is selectedAttorney Docket No.: SP24-243 to facilitate the flow of the liquid-assist medium 60 through the micromachined regions that define a tube-like modification 121.

[0107] FIG. 2D is a close-up view of the irradiated portion of the substrate 100showing the completed formation of the example of a helical modification 121 formed in the body 101 of the substrate 100 by ablation by the focal spot FS moving over the example helical motion path MP of FIG.2B. Just the liquid-assist medium 60 of the cuvette is shown for ease of illustration. Localized micromachining occurs in the vicinity of each position of the focal spot FS within the body 101 of the substrate 100 when forming the modification 121. For the helical modification 121, a helical arrangement of micromachined regions 123 is formed in the body 101 of the substrate 100, as shown in the close-up inset 11. The micromachined regions 123 define the modification 121 and constitute regions of mechanical weakness which represent a trajectory for separation of the modification 121 from the rest of the body 101 of the substrate 100. Thus, in an example, the modification 121 can include micromachined regions 123 in the form of microcavities created by ablation and that form contiguous channels within the material that makes up the body 101 of the substrate 100.

[0108] FIGS. 2D and 2E are close-up views of a portion of the substrate 100 andillustrate how a feature 150 in the form of a through-via can be fabricated in the body 101 by moving the focal spot FS over a helical motion path MP so that the micromachined regions that define the modification 121 extend through the thickness TH2 of the body, as shown in FIG. 2E. FIGS.2D and 2E show a core portion 121C of the body 101 as defined by the modification 121, wherein in FIG.2E, the core portion is separated from the rest of the body 101 to form a through-via feature 150. The feature 150 has an interior surface 151.

[0109] Thus, with reference again also to FIGS. 1A and 1B, in an example of theoperation of the system 10, the focused laser beam 22F passes through the body 101 of the substrate 100 so that the focal spot FS resides in the liquid-assist medium 60 adjacent the interface 110 as shown in FIG.2B. The micromachining occurs in a -z direction, i.e., counter to the +z direction of the focused laser beam 22F. That is, relative to the direction of propagation of the focused laser beam 22F, the working surface 104 is closer to the laser source 20 than the initial position of the focal spot FS, and micromachining occurs by moving the focal spot over the motion path MP that has a component in the -z direction, which is toward the working surface 104 and the laser source 20.

[0110] As noted herein, a given modification 121 can be used to form a given feature150, and multiple features can be used to form an array of features. The modifications 121 can have a variety of shapes to form a corresponding variety of features 150. Features 150Attorney Docket No.: SP24-243 other than vias can be similarly fabricated by controlling the motion path MP of the focal spot FS relative to the body 101 of the substrate 100 to form a pattern of two or more ablated regions having a shape consistent with a desired modification 121. Cross-sectional shapes of features 150 include circular, elliptical, round, square, and rectangular. Example features 150 can extend through the entire thickness TH2 of the substrate 100 to form through-vias such as shown in FIG.2E, or alternatively extend through a fraction of the thickness of the substrate (e.g., blind-vias). Generally, the features 150 can include grooves, channels, recesses, holes and slots having arbitrary cross-sectional shapes, cylindrical holes, conical holes, and holes having a combination of conical and cylindrical sections.

[0111] The features 150 can have relatively smooth interior surfaces. The features150 are formed by using the focal spot FS of the focused laser beam 22F laser to remove portions of the material from the body 101 of the substrate. A mechanism of material removal can include a combination of laser ablation and material removal through acoustic shock generated by cavitating bubbles.

[0112] FIG. 3 illustrates a perspective view of an example substrate 100 havingfeatures 150 configured as through-vias formed therethrough.

[0113] To avoid heating and melting of the substrate 100, linear absorption of thefocused laser beam 22F by the substrate can be decreased or minimized and ablation is instead affected by non-linear optical absorption. Non-linear optical absorption occurs in transparent materials when the intensity of the laser exceeds an intensity threshold. The intensity of the laser beam 22 can be controlled by adjusting the power of the laser source and / or the focusing the laser beam by the focusing optical system 40. Non-linear optical absorption is a multiphoton absorption process that has an absorption coefficient that increases with increasing intensity. The high intensity and tight focusing of the focused laser beam 22F can lead to strong non-linear absorption in a highly localized region of the material allowing for dimensional control of features 150 with precision / accuracy of 0.5 microns or smaller.

[0114] The conditions can be controlled to provide absorbed energy that issufficiently high to directly evaporate a portion of the substrate 100 without proceeding through a melting transition. Thermal effects during laser micromachining are further minimized when using pulsed lasers with laser pulses 22P having a pulse duration less than about 100 ps, or less than about 50 ps, or less than about 25 ps. Ablation through non-linear absorption can provide a mechanism for removing material from the substrate 100 andAttorney Docket No.: SP24-243 enables the formation of a select modification 121 via patterning or formation of fine features in the material that makes up the body 101 of the substrate 100.

[0115] In a dry-ablation of material from the substrate 100, debris can form andaccumulate on the first surface 102 or on the interior surface 153. When forming features 150 in the form of through-vias, for example, debris accumulates within the via. The debris is difficult to remove and can interfere with the ablation process by, for example, scattering the laser beam and preventing attainment of the localized intensity needed for non-linear absorption. To aid removal of debris, liquid-based laser micromachining can be performed as described herein. As ablation occurs, the liquid-assist medium 60 displaces debris from the working surface 104 to prevent accumulation of the debris and to provide vias and other features free of clogs. The liquid-assist medium also removes heat from the working surface 104, as noted above. In an example, the liquid-assist medium can assist in pushing the core portion 121C out of the body 101 of the substrate.

[0116] The vertical or near-vertical placement of the substrate 100 in the liquid-assistmedium 60 can allow for better liquid convection behind the substrate 100 and, because of the gap G, in front of the substrate 100, and can allow for the gas bubbles to easily escape from the second surface and the first surface via openings.

[0117] In previous systems, the first surface opening of the features may be chippeddue to the acoustic-shock component of the ablation process. Aspects of the present disclosure address this chipping problem due to acoustic-shock by providing the liquid-assist medium 60 at the first surface of the substrate 100 and within the gap. The liquid-assist medium 60 is denser than air, thus diminishing the acoustic-shock effect, which leads to less chipping as compared to the case where the first surface 102 of the substrate 100 is exposed to air. This occurs because of the much smaller characteristic acoustic impedance difference between water-glass compared to air-glass. Thus, aspects of the present disclosure improve the quality of the via openings at the first surface 102 of the substrate.

[0118] FIGS. 4A and 4B show the first surface openings of 30-micron vias drilled inglass substrates (0.5 mm thick Lotus NXT glass sold by Corning, Inc. of Corning New York) when the first surface was in air and when the first surface was in water, respectively. After forming the vias, the glass substrates of FIGS. 4A and 4B were water-rinsed in the same way. FIGS.4A and 4B have the same scale. It is shown that the circular shapes of the vias of FIG. 4B are better defined than those of FIG.4A. The holes in FIGS. 4A and 4B have the same diameter. The holes in 4B are closer due to liquid in the gap G.Attorney Docket No.: SP24-243

[0119] Another advantage of the gap G filled with liquid-assist medium 60 is firstsurface cleanliness. When the first surface 102 is in air, micro- and nano-particles from the ablation process spill over the first surface 102 when the laser-machined channel breaks through it. In the microscope photo of FIG. 4A, the first surface is shown after the drilling ended. The contamination cannot be washed away because of the strong adhesion of the ablation byproducts to the surface and mechanical finishing is required. When using the system of the present disclosure, the substrate needs rinsing only after completion because the liquid within the gap prevents surface adhesion of debris (see FIG.4B).

[0120] Additionally, the methods described herein can provide for high-qualityinterior walls. Particularly, the presence of the liquid-assist medium 60 at the first surface 102 can enable features 150 having walls with a surface roughness of less than or equal to 2 microns, or less than or equal to 2 microns, or less than or equal to 1 micron, or less than or equal to 0.2 microns. The waviness of the walls of the features may be less than or equal to 3 micron, less than equal to 2 microns, or less than or equal to 1 micron. Referring to FIG.5, the surface roughness and waviness of the wall 152 of a feature 150 may be measured by first dicing the substrate 100 through the feature 150 along a dicing plane 159 and then measuring the wall 152 with an interferometer (e.g., a Zygo interferometer). The opening of the feature 150 allows the wall 152 to measure for surface roughness by an interferometer. The substrate 100 may be diced by any appropriate method, such as mechanically by a dicing blade or by laser ablation.

[0121] FIG. 5 also illustrates how the shape of the feature 150 can be cylindricalthrough the thickness of the substrate 100 from the first surface 102 to the second surface 104. The presence of the liquid-assist medium at both the first surface 102 and the second surface 104 enables very small features (e.g., blind or through-vias having a diameter within a range of 10 microns to 200 microns including endpoints, a range of 10 microns to 100 microns including endpoints, or a range of 10 microns to 50 microns including endpoints) that have a profile extending from a first surface to a second surface that closely matches a desired profile. For example, a cylindrical via has a cylindrical profile whereas a square via has a square profile defined by parallel walls. In aspects, the profile of the through-via does deviates less than 5 microns from a predefined profile. Thus, a cylindrical feature fabricated by the methods described herein has a substantially cylindrical profile that deviates less than 5 microns from a cylindrical profile.

[0122] A previous method of fabricating small through-features is a laser damage andthen etch process wherein a laser first damages a substrate and then an etching bath etches theAttorney Docket No.: SP24-243 damaged portion which creates the through-feature. However, this method results in through- features that are hourglass-shaped, with the opening at one or both surfaces being larger than a central waist of the through-feature. Conversely, the methods described herein result in a through-feature 150 having a profile that does not deviate from a cylindrical profile by more than 5 microns.

[0123] Another aspect of the approach of the present disclosure is the capability ofplacing the laser-micromachined features in close proximity to one another. Without first surface immersion, there are two factors preventing features (e.g., vias) from being placed close to each other: 1) chipping of the neighboring via and its partial filling with liquid distort and clip the laser beam due to the refractive index spatial variations (as discussed herein with respect to FIG.6A and 6B), and 2) the contaminated surface attenuates and scatters the laser beam.

[0124] Accordingly, having the gap G filled with the liquid-assist medium 60 enablessmall features 150 having a diameter of less than or equal to 200 microns and large aspect ratios (e.g., greater than 10:1 (thickness to diameter), greater than 15: 1, or greater than 20:1) to be placed close to an edge or one another. An individual feature 150 may be fabricated within 10 microns to 100 microns, including endpoints, from an edge of the substrate 100 and / or an edge of an adjacent feature. The feature 150 will be partially or completely air- filled if drilled with surface 102 in contact with air (i.e., without liquid in the gap G).

[0125] Without liquid in the gap G, the distance d of an edge of an air-filled feature150 from an edge of a substrate 100 and / or an edge of another feature depends on a thickness TH2 of the substrate 100 and the focusing angle of the focused laser beam 22F. FIG.6A illustrates a cross-section of an example substrate 100 having a feature 150 and a focused laser beam 22F in the process of fabricating a second, adjacent feature. The substrate has athickness TH2, and the focused laser beam 22F has a focusing angle ^.

[0126] FIG. 6B is a microscope image showing the proximity placement advantage ofproviding liquid-assist media to the first surface during the micromachining process, where 30-micron vias are created with less than 40 microns distance from the edge and approximately 50 microns center-to-center. Aspects of the present disclose enable circular through-vias to be formed having a dimeter of at least 15 microns. Features may be positioned 40 microns or less from the edge of substrate, with edge-to-edge spacing between features being 20 microns or less. Without being bound by theory, it is believed that thisAttorney Docket No.: SP24-243 improvement is possible because the refractive index mismatch of about 0.45 between air and glass is reduced to about 0.12 between water and glass.

[0127] In some aspects, the system 10 may be used to fabricate features directly on anedge of a substrate. FIG.7A illustrates a substrate 100’ having three features 150A, 150B, and 150C formed directed in an edge 107 of the substrate 100’ that extends from the first surface 102 to the second surface 104. The formation of a feature on an edge 107 of the substrate 100' is not possible when the first surface 102 is exposed to air (i.e., without the liquid-filled gap) because of laser beam clipping by the edge of the substrate 100’. The small refractive index mismatch between the liquid-assist material 60 and the substrate material enables such edge features to be fabricated. FIG.7B illustrates a photograph of a feature formed directly on an edge of a substrate using the system 10. The feature is similar to feature 150A in FIG.7A and has a width of 204 microns. Substrate including at least one via.

[0128] Various aspects of the present invention provide a substrate including at leastone via. The substrate including the via can be any suitable substrate including at least one via that can be formed using one or more aspects of the method of processing a substrate described herein or of the system for processing a substrate described herein.

[0129] The substrate includes at least one via that includes at least one opening on afirst surface of the substrate and at least one opening on a second surface of the substrate. The via can include any suitable number of openings on the first and second surface of the substrate. The via can include a different number of openings on the first surface of the substrate than the second surface of the substrate. The via can include two openings on one end of the via and one opening on an opposite end of the via (e.g., a via having a Y-shaped or V-shaped side profile). The via can include two openings on one end of the via and two openings on an opposite end of the via (e.g., a via having an X-shaped side profile). The via can include three openings on one end of the via and one opening on an opposite end of the via. A side-profile of the via can have a Y-shape, a V-shape, or an X-shape. The via can be a bifurcated via. The via can be a trifurcated via.

[0130] The cross-sectional profile of the via (e.g., perpendicular to a longitudinaldirection of the via) can have any suitable shape. For example, the cross-sectional profile of the via can be circular, elliptical, round, square, rectangular, polygonal, or a combination thereof. The cross-sectional profile can vary along its length or be consistent along its length. The cross-sectional profile of the via can be circular with a consistent diameter such that theAttorney Docket No.: SP24-243 via is a cylindrical via. In various aspects, a cross-sectional profile of the via can deviate from a predefined cross-sectional profile by an amount that is less than or equal to 5 microns, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, or less than or equal to 0.5 microns.

[0131] The via can have a maximum cross-sectional size (e.g., diameter) of 15microns to 500 microns, or 15 microns to 250 microns, or 15 microns to 100 microns, or less than or equal to 500 microns and greater than or equal to 15 microns and less than, equal to, or greater than 20 microns, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 120, 140, 160, 180, 200, 250, 300, 350, 400, or 450 microns. The via can have a ratio of a maximum cross-sectional size of the via (e.g., diameter) to a length of the via of 1:10 or less, or 1:25 or less, or 1:50 or less. The via can have a ratio of a maximum cross-sectional size of the via to a thickness of the substrate in a location of the via of 1:10 or less, or 1:25 or less, or 1:50 or less.

[0132] The method of formation of the via in the substrate can affect the cross-sectional profile of the via. For example, the method of the present disclosure can be used to form the via using the laser to drill a circumferential outline of the via leaving a core in the via which is later removed. The circumferential outline can be formed using a helical motion path of the focal spot. Drilling the circumferential outline around the core using a helical motion path can produce striations in the via running approximately perpendicular to a longitudinal direction of the via, as shown in FIG.11A which illustrates a photograph of a via having a diameter of 100 microns formed using a helical motion path to drill a circumferential outline around the core. In another example, the method of the present disclosure can be used to form the via using the laser to completely ablate the interior of the via such that the via is formed with no core therein. Completely ablating the interior of the via can produce a via that is substantially free of striations in the via running approximately perpendicular to the longitudinal axis of the via, as shown in FIG.11B which illustrates a photograph of a via having a diameter of 100 microns formed with complete ablation of the interior of the via.

[0133] Various aspects of the present disclosure provide a substrate including at leastone via including at least one opening on a second surface of the substrate. The via can include at least one passage terminating in a blind hole. The via can be free of openings on surfaces of the substrate other than the second surface. The via can include more than one opening on the second surface of the substrate and / or more than one of the passages terminating in a blind hole.Attorney Docket No.: SP24-243

[0134] Various aspects of the present disclosure provide a substrate including at leastone via including more than one opening on the second surface of the substrate. The via can be free of openings on surfaces of the substrate other than the second surface. Examples

[0135] Various aspects of the present invention can be better understood by referenceto the following Examples which are offered by way of illustration. The present invention is not limited to the Examples given herein.

[0136] The Examples were performed using the system illustrated in FIGS. 1A and1B. A laser operating at 1030-nm wavelength and 10-ps pulse duration, was utilized for the experiments. The process power was 150 mW, while the laser output was up to 50 W. This approach allowed for creating vias of arbitrary shapes, profiles, and aspect ratios (length to diameter) exceeding 15:1-20:1.

[0137] FIG. 8A illustrates an isometric view of an array of 60-micron and 115-micronthrough-vias in a 1.1 mm thick IRIS glass substrate. FIG.8B illustrates a top view of the array shown in FIG.8B. The vias shown in FIGS.8A-8B had a 300-µm pitch. The drilling time was about 6 s for the 60-micron vias and about 23 s for the 115-micron vias. The process did not produce any hazardous products and was a one-step process. The precision of placement and diameter control was limited by the motion control equipment accuracy and by approximately 200 nm RMS inner wall roughness and waviness. The vias shown in FIGS. 8A-8B have a round cross-sectional profile; however, the method can be performed with the cross-sectional profile and side-profile controlled for each via independently.

[0138] FIG. 9A illustrates an isometric via of an array of V-shaped vias in 1.1 mmthick IRIS glass substrate. FIG. 9B illustrates a top view of the array of vias shown in FIG. 9A. The vias shown in FIGS.9A-9B have a 60-micron diameter and are split at a 7.5° angle. Such configuration may be advantageous for power or signal delivery from one side of the substrate to the other by limiting the number of via openings. Such configuration can increase the mechanical strength of the substrate.

[0139] FIG. 10A illustrates an isometric view of an array of Y-shaped vias. FIG. 10Billustrates front, side, and back views of the array of vias shown in FIG.10A. Y-shaped vias can be convenient for distributed signal or power delivery across the substrate.

[0140] The terms and expressions that have been employed are used as terms ofdescription and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portionsAttorney Docket No.: SP24-243 thereof, but it is recognized that various modifications are possible within the scope of the aspects of the present invention. Thus, it should be understood that although the present invention has been specifically disclosed by specific aspects and optional features, modification and variation of the concepts herein disclosed may be resorted to by those of ordinary skill in the art, and that such modifications and variations are considered to be within the scope of aspects of the present invention. Exemplary Aspects.

[0141] The following exemplary aspects are provided, the numbering of which is notto be construed as designating levels of importance:

[0142] Aspect 1 provides a method of processing a substrate, the method comprising:directing a pulsed laser beam through a window-substrate, wherein a mount assembly comprises the window-substrate and one or more spacers located at a surface of the window- substrate, wherein a substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein a liquid-assist medium is present within the gap and at a second surface of the substrate, to form a focal spot within the liquid assist medium; moving the focal spot over a motion path through the second surface of the substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally comprising a core therein; and optionally removing the core from the via, wherein the via comprises more than one opening on the second surface of the substrate and / or on the first surface of the substrate.

[0143] Aspect 2 provides the method of Aspect 1, wherein the via comprises adifferent number of openings on the first surface of the substrate than the second surface of the substrate.

[0144] Aspect 3 provides the method of any one of Aspects 1-2, wherein the viacomprises two openings on one end of the via and one opening on an opposite end of the via.

[0145] Aspect 4 provides the method of any one of Aspects 1-2, wherein the viacomprises two openings on one end of the via and two openings on an opposite end of the via.

[0146] Aspect 5 provides the method of any one of Aspects 1-2, wherein the viacomprises three openings on one end of the via and one opening on an opposite end of the via.Attorney Docket No.: SP24-243

[0147] Aspect 6 provides the method of any one of Aspects 1-4, wherein a side-profile of the via has a Y-shape, a V-shape, or an X-shape.

[0148] Aspect 7 provides the method of any one of Aspects 1-3 and 6, wherein the viais a bifurcated via.

[0149] Aspect 8 provides the method of any one of Aspects 1-7, wherein a cross-sectional profile of the via is circular, elliptical, round, square, rectangular, polygonal, or a combination thereof.

[0150] Aspect 9 provides the method of any one of Aspects 1-8, wherein a cross-sectional profile of the via is cylindrical.

[0151] Aspect 10 provides the method of any one of Aspects 1-9, wherein a cross-sectional profile of the via deviates from a predefined cross-sectional profile by an amount that is less than or equal to 5 microns.

[0152] Aspect 11 provides the method of any one of Aspects 1-10, wherein the viahas a maximum cross-sectional size of 15 microns to 500 microns.

[0153] Aspect 12 provides the method of any one of Aspects 1-11, wherein the viahas a ratio of a maximum cross-sectional size of the via to a length of the via of 1:25 or less.

[0154] Aspect 13 provides the method of any one of Aspects 1-12, wherein the viahas a ratio of a maximum cross-sectional size of the via to a thickness of the substrate in a location of the via of 1:10 or less.

[0155] Aspect 14 provides the method of any one of Aspects 1-13, wherein thesecond surface of the substrate is a back of the substrate, and wherein the first surface of the substrate is a front of the substrate.

[0156] Aspect 15 provides the method of any one of Aspects 1-14, wherein thesecond surface of the substrate is a side surface of the substrate, and wherein the first surface of the substrate is a front surface of the substrate.

[0157] Aspect 16 provides the method of any one of Aspects 1-15, wherein thesecond surface of the substrate is a side surface of the substrate, wherein the via comprises one or more openings on a side surface of the substrate and is free of openings on a back of the substrate.

[0158] Aspect 17 provides the method of any one of Aspects 1-16, wherein thesecond surface of the substrate is a back of the substrate, wherein the via comprises one or more openings on a back of the substrate and is free of openings on a side surface of the substrate.Attorney Docket No.: SP24-243

[0159] Aspect 18 provides the method of any one of Aspects 1-17, wherein themotion path comprises the shape of a straight line.

[0160] Aspect 19 provides the method of any one of Aspects 1-18, wherein themotion path comprises a helical shape.

[0161] Aspect 20 provides the method of any one of Aspects 1-19, wherein themotion path comprises the shape of a curved line.

[0162] Aspect 21 provides the method of any one of Aspects 1-18, wherein themotion path has a Y-shape, a V-shape, or an X-shape.

[0163] Aspect 22 provides the method of any one of Aspects 1-21, wherein the via isfree of portions that intersect a side surface or edge of the substrate.

[0164] Aspect 23 provides the method of any one of Aspects 1-21, wherein at leastone portion of the via intersects a side surface or edge of the substrate.

[0165] Aspect 24 provides the method of any one of Aspects 1-23, wherein the mountassembly is attached to an opening of a cuvette, and the liquid-assist medium is provided within the cuvette.

[0166] Aspect 25 provides the method of any one of Aspects 1-24, wherein the gaphas a thickness of 0.06 mm to 1.6 mm.

[0167] Aspect 26 provides the method of any one of Aspects 1-25, wherein thesubstrate has a transmittance of more than 50% at a wavelength of the pulsed laser beam.

[0168] Aspect 27 provides the method of any one of Aspects 1-26, wherein thewindow-substrate has a transmittance of greater than or equal to 80% at a wavelength of the pulsed laser beam.

[0169] Aspect 28 provides the method of any one of Aspects 1-27, wherein thesubstrate comprises glass, glass-ceramic, a crystalline material, a transparent dielectric material, or a polymer material.

[0170] Aspect 29 provides the method of any one of Aspects 1-28, wherein thesubstrate is a glass substrate.

[0171] Aspect 30 provides the method of any one of Aspects 1-29, wherein thesubstrate is a planar substrate.

[0172] Aspect 31 provides the method of any one of Aspects 1-30, wherein thesubstrate has a thickness of 50 microns to 10 mm.

[0173] Aspect 32 provides the method of any one of Aspects 1-31, wherein thesubstrate has a thickness of less than or equal to 2 mm.Attorney Docket No.: SP24-243

[0174] Aspect 33 provides the method of any one of Aspects 1-32, wherein thesubstrate has a thickness of less than or equal to 1.2 mm.

[0175] Aspect 34 provides the method of any one of Aspects 1-33, wherein the liquid-assist medium has a boiling point greater than or equal to 80 °C.

[0176] Aspect 35 provides the method of any one of Aspects 1-34, wherein adifference in a refractive index of the liquid-assist medium and a refractive index of the substrate is less than 0.3.

[0177] Aspect 36 provides the method of any one of Aspects 1-35, wherein the liquid-assist medium has a surface tension of less than or equal to 72 dynes / cm at 25 °C.

[0178] Aspect 37 provides the method of any one of Aspects 1-36, wherein the liquid-assist medium comprises water, an organic solvent, or a combination thereof.

[0179] Aspect 38 provides the method of any one of Aspects 1-37, wherein the liquid-assist medium is selected from one or more of water, water with added surfactants, a fluorinated alkane, a fluorinated alcohol, a fluorinated amine, methanol, ethanol, acetone, dimethyl sulfoxide, ethylene glycol, and a perfluorinated compound.

[0180] Aspect 39 provides the method of any one of Aspects 1-38, wherein the liquid-assist medium is substantially free of acid.

[0181] Aspect 40 provides the method of any one of Aspects 1-39, wherein the liquid-assist medium is substantially free of base.

[0182] Aspect 41 provides the method of any one of Aspects 1-40, wherein themotion path of the beam is parallel to an axis of the beam.

[0183] Aspect 42 provides the method of any one of Aspects 1-40, wherein themotion path of the beam is not parallel to an axis of the beam.

[0184] Aspect 43 provides the method of any one of Aspects 1-42, wherein the focalspot has a circular profile.

[0185] Aspect 44 provides the method of any one of Aspects 1-42, wherein the focalspot has a non-circular profile.

[0186] Aspect 45 provides the method of any one of Aspects 1-44, wherein themotion path of the beam comprises an angle with respect to an axis of the beam of from equal to or greater than 0 degree to equal to or less than 90 degrees.

[0187] Aspect 46 provides the method of any one of Aspects 1-45, wherein themethod comprises maintaining an angle between the axis of the beam and the first and / or second surface of 80 degrees to 90 degrees during the moving the focal spot over the motion path.Attorney Docket No.: SP24-243

[0188] Aspect 47 provides the method of any one of Aspects 1-46, wherein themethod comprises maintaining the beam substantially perpendicular to the first and / or second surface of the substrate during the moving the focal spot over the motion path.

[0189] Aspect 48 provides the method of any one of Aspects 1-47, further comprisingperforming the directing, moving, and removing two or more times to form two or more of the vias.

[0190] Aspect 49 provides the method of Aspect 48, wherein the method comprisesforming the two or more vias in series.

[0191] Aspect 50 provides the method of any one of Aspects 48-49, wherein themethod comprises forming the two or more vias at least partially simultaneously.

[0192] Aspect 51 provides the method of any one of Aspects 48-50, wherein the twoor more vias form an array of the vias in the substrate.

[0193] Aspect 52 provides the method of any one of Aspects 48-51, wherein at leasttwo of the two or more vias have a different side-profile and / or cross-sectional profile.

[0194] Aspect 53 provides the method of any one of Aspects 48-52, wherein at leasttwo of the two or more vias have a different number of openings on the first surface and / or a different number of openings on the second surface.

[0195] Aspect 54 provides the method of any one of Aspects 48-53, wherein adistance between at least a portion of the two or more vias within the substrate is less or equal to 20 microns.

[0196] Aspect 55 provides a method of processing a substrate, the methodcomprising: directing a pulsed laser beam through a window-substrate, wherein a mount assembly comprises the window-substrate and one or more spacers located at a surface of the window- substrate, wherein a substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein the liquid-assist medium is present within the gap and at a second surface of the substrate, to form a focal spot within the liquid assist medium; moving the focal spot over a motion path through the second surface of the substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally comprising a core therein; maintaining an angle between an axis of the beam and the first and / or second surface of 80 degrees to 90 degrees throughout the moving of the focal spot over the motion path,Attorney Docket No.: SP24-243 wherein the motion path of the beam comprises an angle with respect to the axis of the beam of from equal to or greater than 0 degree to equal to or less than 90 degrees; and optionally removing the optional core from the via.

[0197] Aspect 56 provides a method of processing a substrate, the methodcomprising: directing a pulsed laser beam through a window-substrate, wherein a mount assembly comprises the window-substrate and one or more spacers located at a surface of the window- substrate, wherein a substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein a liquid-assist medium is present within the gap and at a second surface of the substrate, to form a focal spot within the liquid assist medium; moving the focal spot over a motion path through the second surface of the substrate and through a body of the substrate, to create a via in the substrate optionally comprising a core therein; and optionally removing the optional core from the via, wherein the via comprises at least one passage terminating in a blind hole, wherein the via is free of openings on surfaces of the substrate other than the second surface, and wherein the via comprises more than one opening on the second surface of the substrate and / or more than one of the passages terminating in a blind hole.

[0198] Aspect 57 provides a method of processing a substrate, the methodcomprising: directing a pulsed laser beam through a window-substrate, wherein a mount assembly comprises the window-substrate and one or more spacers located at a surface of the window- substrate, wherein a substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein a liquid-assist medium is present within the gap and at a second surface of the substrate, to form a focal spot within the liquid assist medium; moving the focal spot over a motion path through the second surface of the substrate, through a body of the substrate, and through the second surface of the substrate, to create a via in the substrate optionally comprising a core therein; and optionally removing the optional core from the via, wherein the via comprises more than one opening on the second surface of the substrate, and wherein the via is free of openings on surfaces of the substrate other than the second surface.Attorney Docket No.: SP24-243

[0199] Aspect 58 provides a system for processing a substrate, the systemcomprising: a laser system comprising a laser operable to produce a pulsed laser beam; and a mount assembly comprising a window-substrate and one or more spacers located at a surface of the window-substrate, wherein the one or more spacers are configured to attach to a substrate such that a gap is present between a first surface of the substrate and the surface of the window-substrate, wherein the system is configured such that a liquid-assist medium is disposable within the gap and at a second surface of the substrate; and an optical assembly operable to focus the pulsed laser beam through the window- substrate to a focal spot within the liquid medium and move the focal spot along a motion path through the second surface of a substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally comprising a core therein; wherein after optional removal of the optional core from the via, the via comprises more than one opening on the second surface of the substrate and / or on the first surface of the substrate.

[0200] Aspect 59 provides a system for processing a substrate, the systemcomprising: a laser system comprising a laser operable to produce a pulsed laser beam; a mount assembly comprising a window-substrate and one or more spacers located at a surface of the window-substrate, wherein the one or more spacers are configured to attach to a substrate such that a gap is present between a first surface of the substrate and the surface of the window-substrate, wherein the system is configured such that a liquid-assist medium is disposable within the gap and at a second surface of the substrate; and an optical assembly operable to focus the pulsed laser beam through the window- substrate to a focal spot within the liquid medium and move the focal spot along a motion path through the second surface of a substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate optionally comprising a core therein, wherein the system is configured to maintain an angle between an axis of the beam and the first and / or second surface of 80 degrees to 90 degrees throughout the moving of the focal spot over the motion path, wherein the motion path of the beam comprises an angle with respect to the axis of the beam of from greater than 0 degrees to equal to or less than 90 degrees.

[0201] Aspect 60 provides a substrate comprising:Attorney Docket No.: SP24-243 at least one via comprising at least one opening on a second surface of the substrate and at least one opening on a first surface of the substrate, wherein the via comprises more than one of the openings on the second surface of the substrate and / or more than one of the openings on the first surface of the substrate.

[0202] Aspect 61 provides the substrate of Aspect 60, wherein the via comprises adifferent number of openings on the second surface of the substrate than the first surface of the substrate.

[0203] Aspect 62 provides the substrate of any one of Aspects 60-61, wherein the viacomprises two openings on one end of the via and one opening on an opposite end of the via.

[0204] Aspect 63 provides the substrate of any one of Aspects 60-62, wherein the viacomprises two openings on one end of the via and two openings on an opposite end of the via.

[0205] Aspect 64 provides the substrate of any one of Aspects 60-63, wherein the viacomprises three openings on one end of the via and one opening on an opposite end of the via.

[0206] Aspect 65 provides the substrate of any one of Aspects 60-64, wherein a side-profile of the via has a Y-shape, a V-shape, or an X-shape.

[0207] Aspect 66 provides the substrate of any one of Aspects 60-65, wherein the viais a bifurcated via.

[0208] Aspect 67 provides the substrate of any one of Aspects 60-66, wherein a cross-sectional profile of the via is circular, elliptical, round, square, rectangular, polygonal, or a combination thereof.

[0209] Aspect 68 provides the substrate of any one of Aspects 60-67, wherein a cross-sectional profile of the via is cylindrical.

[0210] Aspect 69 provides the substrate of any one of Aspects 60-68, wherein a cross-sectional profile of the via deviates from a predefined cross-sectional profile by an amount that is less than or equal to 5 microns.

[0211] Aspect 70 provides the substrate of any one of Aspects 60-69, wherein the viahas a maximum cross-sectional size of 15 microns to 500 microns.

[0212] Aspect 71 provides the substrate of any one of Aspects 60-70, wherein the viahas a ratio of a maximum cross-sectional size of the via to a length of the via of 1:25 or less.

[0213] Aspect 72 provides the substrate of any one of Aspects 60-71, wherein the viahas a ratio of a maximum cross-sectional size of the via to a thickness of the substrate in a location of the via of 1:10 or less.Attorney Docket No.: SP24-243

[0214] Aspect 73 provides the substrate of any one of 60-72, wherein the via issubstantially free of striations running approximately perpendicular to a longitudinal direction of the via.

[0215] Aspect 74 provides the substrate of any one of 60-72, wherein the viacomprises striations running approximately perpendicular to a longitudinal direction of the via.

[0216] Aspect 75 provides a substrate comprising:at least one via comprising at least one opening on a second surface of the substrate, wherein the via comprises at least one passage terminating in a blind hole, wherein the via is free of openings on surfaces of the substrate other than the second surface, and wherein the via comprises more than one opening on the second surface of the substrate and / or more than one of the passages terminating in a blind hole.

[0217] Aspect 76 provides a substrate comprising:at least one via comprising more than one opening on a second surface of the substrate, wherein the via is free of openings on surfaces of the substrate other than the second surface.

[0218] Aspect 77 provides the method, system, or substrate of any one or anycombination of Aspect 1-76 optionally configured such that all elements or options recited are available to use or select from.

Claims

Attorney Docket No.: SP24-243 CLAIMS What is claimed is:

1. A method of processing a substrate, the method comprising:directing a pulsed laser beam through a window-substrate, wherein a mount assembly comprises the window-substrate and one or more spacers located at a surface of the window- substrate, wherein a substrate is attached to the one or more spacers such that a gap is present between a first surface of the substrate and the surface of the window-substrate, and wherein a liquid-assist medium is present within the gap and at a second surface of the substrate, to form a focal spot within the liquid assist medium; and moving the focal spot over a motion path through the second surface of the substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate; wherein the via comprises more than one opening on the second surface of the substrate and / or on the first surface of the substrate.

2. The method of claim 1, wherein via created by the moving of the focal spot over themotion path comprises a core therein, wherein the method further comprises removing the core portion from the via.

3. The method of any one of claims 1-2, wherein a side-profile of the via has a Y-shape,a V-shape, or an X-shape.

4. The method of any one of claims 1-3, wherein a cross-sectional profile of the via iscircular.

5. The method of any one of claims 1-4, wherein a cross-sectional profile of the viadeviates from a predefined cross-sectional profile by an amount that is less than or equal to 5 microns.

6. The method of any one of claims 1-5, wherein the via has a maximum cross-sectionalsize of 15 microns to 500 microns, and wherein the via has a ratio of a maximum cross- sectional size of the via to a length of the via of 1:25 or less.Attorney Docket No.: SP24-2437. The method of any one of claims 1-6, wherein the gap has a thickness of 0.06 mm to1.6 mm.

8. The method of any one of claims 1-7, wherein the substrate has an internaltransmittance of greater than or equal to 70% at a wavelength of the pulsed laser beam.

9. The method of any one of claims 1-8, wherein the substrate comprises glass, glass-ceramic, a crystalline material, a transparent dielectric material, or a polymer material.

10. The method of any one of claims 1-9, wherein the substrate has a thickness of less than or equal to 2 mm.

11. The method of any one of claims 1-10, wherein the liquid-assist medium has a boiling point greater than or equal to 80 °C.

12. The method of any one of claims 1-11, wherein a difference in a refractive index of the liquid-assist medium and a refractive index of the substrate is less than 0.

3.

13. The method of any one of claims 1-12, wherein the liquid-assist medium comprises water, an organic solvent, or a combination thereof.

14. The method of any one of claims 1-13, wherein the liquid-assist medium is substantially free of acid and base.

15. The method of any one of claims 1-14, wherein the motion path of the beam comprises an angle with respect to an axis of the beam of from equal to or greater than 0 degree to equal to or less than 90 degrees, and wherein the method comprises maintaining an angle between the axis of the beam and the second and / or first surface of 80 degrees to 90 degrees during the moving the focal spot over the motion path.

16. The method of any one of claims 1-15, further comprising performing the directing, moving, and removing two or more times to form two or more of the vias.Attorney Docket No.: SP24-243 17. The method of claim 16, wherein at least two of the two or more vias have a different side-profile and / or cross-sectional profile, and / or wherein at least two of the two or more vias have a different number of openings on the second surface and / or a different number of openings on the first surface.

18. The method of any one of claims 16-17, wherein a distance between at least a portion of the two or more vias within the substrate is less or equal to 20 microns.

19. A system for processing a substrate, the system comprising: a laser system comprising a laser operable to produce a pulsed laser beam; and a mount assembly comprising a window-substrate and one or more spacers located at a surface of the window-substrate, wherein the one or more spacers are configured to attach to a substrate such that a gap is present between a first surface of the substrate and the surface of the window-substrate, wherein the system is configured such that a liquid-assist medium is disposable within the gap and at a second surface of the substrate; and an optical assembly operable to focus the pulsed laser beam through the window- substrate to a focal spot within the liquid medium and move the focal spot along a motion path through the second surface of a substrate, through a body of the substrate, and through the first surface of the substrate, to create a via in the substrate; wherein the via comprises more than one opening on the second surface of the substrate and / or on the first surface of the substrate.

20. A substrate comprising: at least one via comprising at least one opening on a second surface of the substrate and at least one opening on a first surface of the substrate, wherein the via comprises more than one of the openings on the second surface of the substrate and / or more than one of the openings on the first surface of the substrate.

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