A method of forming an aperture through a substrate using a liquid-jet guided laser beam

Abstract

Precision micro-holes can be machined in thick substrates using a combination of a liquid jet and a mechanical rotary tool. A liquid jet-guided laser can be used to rapidly drill core holes in the ceramic substrate. A sensor can be applied to detect the cut point of the liquid jet-guided laser drilling step, allowing for a fast and closed-loop controlled machining process. The substrate can be heated to accelerate the liquid jet-guided laser drilling process. A mechanical tool (e.g., a drill, a reamer, or a milling cutter) can be used to finish these core holes to a desired bore diameter. The primary surface cut by the mechanical tool can preferably be composed of a diamond material. As part of the drilling process, an inspection camera and illumination system can be used to inspect each machined bore.

Description

Technical Field

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 060 016, filed January 8, 2020, entitled “Methods and systems for machining precision micro bores into thick ceramic substrates,” which is incorporated herein by reference. Prior Technology

[0002] For example, precision components of gas distribution and homogenization plates used in semiconductor processing equipment typically require hundreds or even thousands of precision holes machined into thick ceramic substrates. To avoid contaminating silicon or silicon carbide product wafers, these gas distribution and homogenization plates are usually made of materials of equal or higher purity (e.g., silicon or silicon carbide). In addition to the large number of holes, these holes further require a high level of surface finishing. The inner walls of each hole must be mirror-smooth to prevent the adhesion of unwanted particles that could potentially contaminate the actual product wafers. To ensure stable and repeatable gas distribution, the inlet and outlet of each hole must have sharp edges without any circumferential damage.

[0003] Currently, holes in gas distribution plates and homogenization plates are manufactured in various ways. They can be drilled sequentially using a drill bit. Alternatively, holes can be manufactured sequentially using an electrical discharge machining (EDM) process, in which the material inside the hole is eroded by a metal wire. Another method is to simultaneously machine all holes or groups of holes using an ultrasonic plate, which removes the material inside the hole by means of ultrasonic vibrations applied to a pin pattern opposite to the pin pattern of the hole to be machined. Alternatively, all holes or groups of holes can be simultaneously machined using an EDM process using an electrode plate having a pin pattern opposite to the pin pattern of the hole to be eroded.

[0004] While methods that simultaneously create holes via ultrasonic processing or electrical discharge machining can be relatively fast, each hole typically requires a post-processing step (e.g., reaming) to achieve the desired mirror-like surface finish. Without any post-processing, the desired mirror-like surface finish can usually be achieved by sequentially drilling holes with milling tools. However, drilling with mechanical drilling tools may introduce an increased risk of material breakage at the inlet and, specifically, on the outlet side of the hole. Furthermore, when processing ceramic materials (e.g., but not limited to silicon and silicon carbide), there is substantial wear on the drilling tools and a limited tool life.

[0005] A typical gas distribution and / or homogenization plate can be 10 to 15 mm thick and has 1,000 to 2,000 holes with a diameter of 0.2 to 0.8 mm. Each hole can be drilled in 3 to 4 minutes. If the drill bit breaks at, for example, the 1,480th hole out of 1,500, the entire substrate may potentially be scrapped, and many hours of machining work will be lost. Therefore, there is a substantial need for an improved and more efficient method for machining many small holes in thick ceramic substrates. Those skilled in the art will understand that the present invention is not limited to holes in gas distribution and homogenization plates, but is applicable to a wider range of technical ceramic materials and applications requiring precision holes. Summary of the Invention

[0006] In some embodiments, the present invention discloses a method and system for machining precision microholes in a thick substrate. The substrate may be a ceramic material to which hundreds or even thousands of holes are machined. The holes can be created by applying a hybrid process in which a core-hole drilling process and a hole-finishing process are employed. A liquid-jet guided laser can be used to rapidly drill core holes into the ceramic substrate. Sensors can be used to detect the cut points of the liquid-jet guided laser drilling steps to allow for a rapid and closed-loop controlled machining process. The substrate can be heated to accelerate the liquid-jet guided laser drilling process. Mechanical tools (e.g., drills, reamers, or milling cutters) can be used to finish the core holes to the desired hole diameter. The primary surfaces cut by the mechanical tools can preferably be composed of a diamond material. As part of the drilling process, an inspection camera and illumination system can be used to inspect each machined hole. Simple Explanation of the Diagram

[0007] Figures 1A and 1B show a substrate having a series of holes or bores according to some embodiments.

[0008] Figures 2A and 2B illustrate configurations for mixing processes of holes in a substrate according to some embodiments.

[0009] Figures 3A to 3C show flowcharts for forming holes in a substrate according to some embodiments.

[0010] Figure 4 illustrates the configuration of a liquid jet-guided laser head according to some embodiments.

[0011] Figures 5A and 5B illustrate methods for creating holes in a substrate using a laser beam guided by a liquid jet, according to some embodiments.

[0012] Figures 6A and 6B show the sidewall roughness of holes according to some embodiments.

[0013] Figure 7 shows a flowchart of forming an initial hole in a substrate according to some embodiments.

[0014] Figures 8A to 8D show flowcharts for forming initial holes in a substrate according to some embodiments.

[0015] Figures 9A and 9B illustrate configurations of orifices formed by liquid jets according to some embodiments.

[0016] Figures 10A to 10C show flowcharts for forming initial holes in a substrate according to some embodiments.

[0017] Figures 11A to 11D illustrate configurations for heating a substrate to accelerate the laser aperture forming process for guiding liquid jets, according to some embodiments.

[0018] Figures 12A to 12D show flowcharts for adjusting substrate temperature during liquid jet processing according to some embodiments.

[0019] Figures 13A to 13C illustrate sensor configurations for detecting the endpoint of a liquid jet process in a laser process for guiding liquid jets, according to some embodiments.

[0020] Figures 14A and 14B show flowcharts for detecting the endpoint of a liquid jet process according to some embodiments.

[0021] Figures 15A to 15D illustrate the process of forming an initial hole using liquid jet and EDM according to some embodiments.

[0022] Figures 16A and 16B illustrate the process of forming an initial hole using an electrical discharge machine according to some embodiments.

[0023] Figures 17A to 17C show flowcharts of forming holes using an EDM process according to some embodiments.

[0024] Figures 18A and 18B illustrate configurations of forming multiple holes in a substrate using liquid jets according to some embodiments.

[0025] Figure 19 illustrates a closed-loop process for laser drilling holes guided by a liquid jet according to some embodiments.

[0026] Figures 20A and 20B illustrate the process for forming holes according to some embodiments.

[0027] Figures 21A to 21C illustrate the configuration of mechanical rotary tools according to some embodiments.

[0028] Figures 22A to 22C show flowcharts for finishing holes in a substrate according to some embodiments.

[0029] Figures 23A and 23B illustrate the process for finishing initial through holes according to some embodiments.

[0030] Figures 24A to 24C illustrate the process for finishing an initial single-sided blind hole according to some embodiments.

[0031] Figures 25A and 25B illustrate the process for finishing initial double-sided blind holes according to some embodiments.

[0032] Figures 26A and 26B illustrate a process for finishing a hole using two mechanical rotary tools according to some embodiments.

[0033] Figures 27A to 27C show flowcharts for initial holes in a substrate for finishing, according to some embodiments.

[0034] Figures 28A to 28D illustrate configurations for cooling rotary tools according to some embodiments.

[0035] Figures 29A to 29C show flowcharts for cooling mechanical rotating tools according to some embodiments.

[0036] Figures 30A and 30B illustrate the configuration of the alignment module according to some embodiments.

[0037] Figures 31A and 31B show another configuration of the alignment module according to some embodiments.

[0038] Figures 32A and 32B show flowcharts for aligning mechanical rotating tools according to some embodiments.

[0039] Figures 33A and 33B illustrate the configuration of the inspection module according to some embodiments.

[0040] Figures 34A and 34B show flowcharts for inspecting final holes in a substrate according to some embodiments.

[0041] Figure 35 shows a flowchart of a process for fully forming a hole in a substrate according to some embodiments.

[0042] Figure 36 illustrates the configuration of an integrated system of liquid jet and mechanical rotary tools according to some embodiments. Implementation

[0043] In some embodiments, the present invention discloses a method and system for forming holes, such as through-holes or blind vias, in a substrate. The formed holes may have an internal smooth surface with sharp edges at the hole inlet and outlet. The perforated substrate having these internal surface and edge requirements can be used in gas distribution plates and homogenization plates.

[0044] Figures 1A and 1B illustrate a substrate having a series of holes or bores according to some embodiments. Gas distribution and homogenization plates for semiconductor processing equipment are good examples of substrates that typically require a large number of small, precision holes or bores 101 machined in a thick substrate 100. In addition to the large number of holes or bores 101, these holes or bores further require a high level of surface finishing 105, along with undamaged sharp edges 104 at the entrance and exit of the holes or bores. The substrate thickness, such as the depth 103 of the vias or bores (e.g., holes or bores entirely within the substrate), can be less than 20 mm, for example, between 10 mm and 15 mm. The size of the holes or bores, such as the diameter 102 of the holes or bores, can be small, for example, less than 2 mm, for example, between 0.1 mm and 1 mm, to provide uniform gas distribution. Such a substrate 100, for example, a silicon or silicon carbide product wafer, typically has a circular shape and contains hundreds or even thousands of precision holes or bores 101 for use in gas distribution plates and homogenization plates. Circular bores are typical, but for some applications, elongated holes or grooves with circular edges can also be used. In the following description, circular holes are described, for example, holes formed by guiding a liquid jet along a circular profile. However, the invention is not limited to circular holes and further includes elongated holes or grooves with circular edges.

[0045] To avoid contaminating the silicon or silicon carbide substrate, the substrate is typically made of a substrate material of equal or higher purity, such as silicon or silicon carbide. Other materials may also be used, such as aluminum nitride, silicon nitride, titanium nitride, boron carbide, and ceramic matrix composites (CMC) and metal matrix composites (MMC). Furthermore, the substrate may also be a metal substrate and other workpieces with bores or holes.

[0046] Ceramic matrix composites (CMCs) consist of ceramic fibers embedded in a ceramic matrix. Both the fibers and the matrix can be made of any ceramic material, with carbon and carbon fibers considered ceramic materials. CMCs can improve the crack resistance of ceramic materials by embedding particles or long tows of fibers, thus enhancing the fracture toughness of the composite material system while maintaining the high strength and Young's modulus of the ceramic matrix. Carbon (C), specialty silicon carbide (SiC), alumina (Al2O3), and mullite (Al2O3-SiO2) fibers are most commonly used in CMCs. The matrix material of CMCs can be the same, for example, made of carbon, silicon carbide, alumina, and mullite. For example, common CMCs include carbon / carbon, carbon / silicon carbide, silicon carbide / silicon carbide, and alumina / alumina, which can have higher elongation at break, increased fracture toughness, higher thermal shock resistance, and higher dynamic load capacity.

[0047] Metal matrix composites (MMCs) are composite materials having at least one metallic component and different metals or other materials (e.g., ceramics or organic compounds). MMCs can be manufactured by dispersing reinforcing materials into a metallic matrix. For example, carbon fibers can be used in an aluminum matrix to provide high strength at low density.

[0048] In some embodiments, the present invention discloses a hybrid process for forming holes in a substrate, which, for example, can meet the requirements of surface smoothness and edge sharpness without damaging the gas distribution plate. The hybrid process may include, for example, the formation of an initial hole by a liquid jet-guided laser beam generated in a liquid jet-guided laser head of a liquid jet-guided laser system, or alternatively, by an electrical discharge machining (EDM) process. The hybrid process may include, for example, a hole smoothing or finishing process using a mechanical rotary tool (e.g., a drill bit, reamer bit, honing bit, or milling bit). Using a mechanical rotary tool on a pre-existing hole can significantly reduce potential damage to the edges of the finished hole, increasing productivity while reducing wear and tear on the mechanical rotary tool.

[0049] Figures 2A and 2B illustrate configurations for hybrid processing of holes in a substrate according to some embodiments. Figures 2A(a) and 2A(b) show configurations in which the initial hole formation and finishing hole processes are performed in different devices (e.g., forming the initial hole in a liquid jet guided laser system and finishing the hole in a mechanical rotation system). Figures 2B(a) and 2B(b) show configurations in which the initial hole formation and finishing hole processes are performed in the same device (e.g., in a liquid jet guided laser component configured with a mechanical rotation assembly).

[0050] In some embodiments, initial aperture formation can be performed in a liquid jet-guided laser system, which may include a liquid jet-guided laser head coupled to a motion mechanism (e.g., coupled to two-dimensional xy motion or three-dimensional xyz motion). The liquid jet-guided laser head can be configured to generate a liquid jet-guided laser beam, which may be a liquid jet, such as a liquid column, having a laser beam internally reflected within the liquid jet. The liquid jet can constrain the laser beam, for example, by guiding the laser beam into the liquid jet. The liquid jet-guided laser beam can be used, for example, to remove material from a substrate by a laser ablation process.

[0051] Figure 2A(a) illustrates a liquid jet-guided laser head 210 configured to generate a liquid jet-guided laser beam 216, such as a liquid jet 216A, which has a laser beam 216B internally reflected within the liquid jet 216A. The laser beam 216B is configured for, for example, material removal by a laser ablation process. The liquid jet 216A is configured to guide the laser beam 216B, for example, to prevent laser beam divergence.

[0052] A liquid source 214 can be supplied to a nozzle 215 in a liquid jet-guided laser head 210. The nozzle may include an opening through which the liquid jet 216A exits. The laser source 211 can be focused by a lens to form a focused laser beam 213 on the liquid jet 216A. The focused laser beam 213 can then be internally reflected within the liquid jet 216A, for example, thereby forming an internally reflected laser beam 216B.

[0053] The window 212 can be positioned between the focusing lens and the liquid source 214. The window 212 can be configured to allow the laser beam to pass through while preventing liquid from the liquid source 214 from contacting and contaminating the laser components.

[0054] A liquid jet 216 (e.g., a liquid jet-guided laser beam) can be guided onto a substrate 200, for example, to form a through-hole 201* with an initial diameter 206. The liquid jet-guided laser head 210 can move within a closed-loop profile (e.g., a circular or elongated profile), which is essentially a region with circular edges, controlled, for example, by an xy motion mechanism. The liquid jet 216 can remove material from the circular profile to cut a cylinder with an initial diameter 206 similar to the diameter of the circular profile. After the liquid jet 216 passes through the substrate, the cut cylinder can be removed from the substrate, leaving an hole with an initial diameter 206 similar to the diameter of the circular profile.

[0055] The liquid jet-guided laser head 210 can move in a grating path (e.g., in a spiral path or in multiple parallel lines constrained in a closed-loop profile). The liquid jet 216 can remove material from the closed-loop profile by the spiral or grating lines to form an aperture with an initial diameter 206 similar to the diameter of the closed-loop profile.

[0056] Figure 2A(b) shows a mechanical rotary tool head 220 configured to finish an initial hole, for example, to enlarge the initial hole 201* into a final hole 201 with a final diameter 202, while further smoothing the inner surface of the final hole.

[0057] The mechanical rotating tool head 220 may include a mechanical rotating tool 221, which may have a tool diameter 222, similar to the final diameter 202 of the final hole 201. In operation, the mechanical rotating tool 221 can rotate while simultaneously moving downwards 224 into the initial hole 201*. The mechanical rotating tool 221 may have a round or elliptical tip 223, which may be configured to minimize damage to the edges of the final hole 201.

[0058] Figures 2B(a) and 2B(b) illustrate an assembly system 226 comprising a liquid jet-guided laser head 210 and a mechanically hollow rotary tool head 220*. This assembly system 226 can be configured to form an initial hole, along with finishing the initial hole. The liquid jet-guided laser head 210 can be similar to that described above, and can be configured to generate a liquid jet-guided laser beam 216, for example, a liquid jet having a laser beam internally reflected within the liquid jet. The liquid jet-guided laser beam 216 can be configured to, for example, remove cylindrical material by passing through multiple times along a circular profile or to form a hole inside a closed-loop profile by rasterizing multiple times within the closed-loop profile.

[0059] For example, a liquid jet-guided laser head 210 may include a liquid source 214 configured to form a liquid jet 216 after passing through a nozzle 215. A laser source 211 may be focused by a lens to form a focused laser beam 213 on the liquid jet 216. A viewing window 212 may be positioned between the focusing lens and the liquid source 214.

[0060] The hollow mechanical rotating tool head 220* may include a hollow mechanical rotating tool 221*, which may have a conduit 277 through the rotating tool 221*. The hollow mechanical rotating tool head 220* may be positioned such that a liquid jet from a liquid jet-guided laser head can enter the conduit 277, for example, to cool the hollow mechanical rotating tool 221*.

[0061] In operation, substrate 200 is positioned below assembly system 226. Liquid source 214 is turned on to form liquid jet 216. Laser power is turned on to generate a laser beam for internal reflection in liquid jet 216. Liquid jet 216 is configured to pass through mechanical rotating tool head 220*, for example, through conduit 277 without interfering with mechanical rotating tool head 220*. Liquid jet 216 can form holes in substrate having an initial diameter 206 (FIG. 2B(a)).

[0062] After the initial hole is formed, the laser source can be turned off, leaving a liquid jet 216 of the laser beam without internal reflection. The assembly system 226 can move downward 224* while the mechanical rotary tool 221* is rotating to finish the initial hole, for example, to enlarge the initial hole to the final diameter 202 and to make the surface of the final hole smooth (Fig. 2B(b)).

[0063] Figures 3A to 3C illustrate flowcharts for forming holes in a substrate according to some embodiments. Figure 3A shows the hole formation using different or the same equipment. Operation 300 uses a laser beam guided by a liquid jet to form the hole in the substrate. Operation 310 uses a mechanical rotating tool to smooth the hole.

[0064] Figure 3B shows the formation of multiple holes in a substrate using different devices. Operation 330 uses a laser beam guided by a liquid jet controlled by a first motion mechanism on a first platform to form multiple holes in the substrate. Operation 340 uses a mechanical rotary tool controlled by a second motion mechanism on a second platform to smooth the multiple holes.

[0065] Figure 3C shows the formation of a hole in a substrate using a single device. Operation 360, forming the hole in the substrate, may include: opening a liquid supply to a liquid jet-guided laser head to form a liquid column, and opening a laser source to generate a laser beam configured to be internally reflected in the liquid column. Operation 370, smoothing the hole, may include: rotating a mechanical rotating tool while simultaneously opening a liquid supply to the liquid jet-guided laser head to form a liquid column passing through a conduit via the mechanical rotating tool.

[0066] In some embodiments, the present invention discloses forming initial holes in a substrate using a liquid jet-guided laser system. It is known, for example, that liquid jet-guided laser techniques disclosed in U.S. Patent 8,859,988 and U.S. Patent 10,022,820 are capable of machining a wide variety of materials, such as metals and ceramics, including silicon, silicon carbide, aluminum nitride, titanium nitride, boron carbide, ceramic matrix composites (CMC), and metal matrix composites (MMC), all of which are incorporated herein by reference in their entirety.

[0067] Figure 4 illustrates a configuration of a liquid jet-guided laser head according to some embodiments. The liquid jet-guided laser head 410 may include a housing holding a viewing window 412. Below the window 412, a liquid jet nozzle 415 is present. A liquid source (e.g., a water source 414) may be forced into the space between the viewing window 412 and the nozzle 415 to form a layered liquid jet 416A. For material processing, a laser beam 413 from a laser power source is focused and guided through the window 412 and through the orifice of the liquid jet nozzle 415 into the layered liquid jet 416. The focused laser beam 413 may be confined within the liquid column 416A, which can be used by total internal reflection from the inside of the liquid column 416A to direct the energy of the laser beam 416B toward the workpiece substrate 400. The liquid jet-guided laser 416 can be used to precisely machine micro-holes or bore holes 401 in the substrate 400.

[0068] To mitigate potential water backflow interference when drilling or boring small, deep holes 401*, an air jet module, such as the one disclosed in U.S. Patent 10,307,864, can be used. Below the liquid jet nozzle 415, the liquid-jet-guided laser passes through a conduit within the air jet module 427. A high-capacity stream of compressed gas 417 is provided through external and mechanically spaced conduits of the air jet module 427, this high-capacity stream traveling parallel to the liquid-jet-guided laser 416 and toward the surface of the substrate 400. The compressed gas stream 418 acts as a coaxially spaced shield to prevent interference induced by backflow from the liquid-jet-guided laser 416. Other fluids can be used instead of water to perform the liquid-jet-guided laser process.

[0069] The liquid jet-guided laser head 410 can be coupled to a motion mechanism to move the liquid jet-guided laser head, for example, in a plane normal to the liquid jet 416 or in a three-dimensional movement parallel to and normal to the liquid jet 416.

[0070] In some embodiments, a liquid jet-guided laser head can be used to form initial holes in a substrate. A typical liquid jet can have a diameter between 0.02 mm and 0.08 mm, thus allowing the use of hole enlargement processes, such as traveling the liquid jet within a circular profile where the diameter of the circle is equal to the desired hole size. Alternatively, the liquid jet can travel a grating pattern to form holes with grating region dimensions.

[0071] Figures 5A and 5B illustrate a method for drilling holes in a substrate using a liquid jet-guided laser beam according to some embodiments. The diameter of the liquid jet in the liquid jet-guided laser head is typically smaller than the typical hole diameter in a gas distribution plate and homogenization plate; for example, the liquid jet diameter is between 0.02 mm and 0.08 mm, while the hole diameter is between 0.2 mm and 0.08 mm. In operation, the liquid jet 516, which has an internally reflecting laser beam, typically removes material layer by layer by laser ablation, thereby forming a hole of depth. The liquid jet can be continuously sprayed onto the same location on the substrate or pass through multiple times along the same contour on the substrate.

[0072] To form larger holes or bores 501 in the substrate 500, a liquid jet-guided laser 516 can perform a circular machining motion 530 to form a cut 531 and cut out a cylindrical pin 532, or the liquid jet-guided laser 516 can perform a helical motion 533, or a combination of circular and helical motions, to remove all material within the diameter of a blind hole or drill hole 534. Repeated helical motions 533 can form through holes 501 in the substrate 500.

[0073] A liquid jet-guided laser 516 can form holes or bores 501 in a substrate 500, the holes or bores 501 having clean, sharp edge inlets and outlets. The average roughness (Ra) of the sidewalls of the holes or bores 501 formed by the liquid jet-guided laser 516 can be less than 10 micrometers, or between 0.25 micrometers and 3 micrometers, depending on the substrate material and the energy parameters of the laser beam.

[0074] In some embodiments, the surface roughness of the hole sidewalls may depend on the application of a gas distribution plate or a homogenization plate. For high roughness requirements, a hole formed by a laser head guided by a liquid jet is sufficient. For low roughness requirements, a finishing or smoothing process can be performed using a mechanical rotary tool.

[0075] Figures 6A and 6B illustrate the sidewall roughness of a hole according to some embodiments. A liquid jet 616 can be used to form a hole in a substrate 600. Typical hole diameters can be between 0.2 mm and 2 mm, for example, between 0.2 mm and 1 mm or between 0.4 mm and 0.8 mm. Because the diameter of the liquid jet 616 is much smaller, the liquid jet can use circular patterns or grating patterns to enlarge the hole diameter 606. After the liquid jet process, the sidewall roughness of the hole can be 605*. The liquid jet can cut a substrate with a sidewall roughness value, which depends on the substrate material, the energy parameters of the laser beam, and the processing time of the cutting process. For example, a slower cutting process can provide, for example, smoother sidewalls with a lower roughness value, but at the cost of lower throughput. In some embodiments, the hole-forming process can be performed by a high surface roughness process of liquid jetting, followed by a subsequent smoothing process using a mechanical rotary tool to meet the roughness requirements, thereby achieving high throughput. A mechanical rotary tool can smooth the initial sidewall surface 605*hole to a final sidewall roughness 605, while simultaneously enlarging the initial hole diameter 606 to a final hole diameter 602. For example, a mechanical rotary tool can smooth the sidewall to an average roughness Ra of less than a few micrometers (e.g., less than 1 micrometer, less than 0.5 micrometers, or less than 0.1 micrometers).

[0076] In some embodiments, surface roughness can be characterized by an average roughness Ra, which is the arithmetic mean of the filtered roughness profile determined based on the deviation of the centerline within the evaluation length. In practice, Ra can be determined by averaging a set of individual measurements of surface peaks and valleys.

[0077] Figure 7 illustrates a flowchart of forming an initial hole in a substrate according to some embodiments. A liquid jet with an internally reflecting laser beam can be used to form the hole in the substrate. A nozzle of a liquid jet guiding laser head can be used to form the liquid jet. The nozzle can also be aligned with a laser beam to obtain an internally reflecting laser beam. Operation 700: Turn on the liquid supply to the nozzle in the liquid jet guiding laser head to form a liquid column. Operation 710: Turn on the laser power focused on the liquid column to form a laser beam internally reflected in the liquid column. Operation 720: Guide the liquid column with the internally reflecting laser beam onto the substrate to remove material from the substrate. Operation 730: Hold the liquid column with the internally reflecting laser beam in position on the substrate to form a hole in the substrate. Operation 740: Move the liquid column with the internally reflecting laser beam within a closed-loop profile on the substrate to cut a column of material with a closed-loop profile shape in the substrate. Operation 750 rasterizes a liquid column with an internally reflected laser beam in a closed-loop profile on a substrate to form a hole in the substrate by removing material in the closed-loop profile region.

[0078] Figures 8A to 8D illustrate flowcharts of forming initial holes in a substrate according to some embodiments. The holes can be formed by a liquid jet with an internally reflecting laser beam to form a closed-loop profile or grating pattern. The holes can be slightly smaller than the final desired size, which is configured to be smoothed by subsequent processes using mechanical rotary tools (e.g., drills, reamers, milling tools, or honing tools).

[0079] In Figure 8A, operation 800 uses a liquid jet to guide a laser beam to form a hole in a substrate, wherein the liquid jet guides the laser beam to travel in a closed-loop profile (e.g., a circular or elliptical profile), in a grating region containing a spiral path or multiple parallel paths, or in a combination of a closed-loop profile and a grating region.

[0080] In Figure 8B, operation 820 uses a liquid jet to guide a laser beam to form a hole in a substrate, wherein the diameter of the hole is configured to optimize the subsequent smoothing process of the inner surface of the hole.

[0081] In Figure 8C, operation 840 uses a liquid jet to guide a laser beam to form a hole in a substrate, wherein the diameter of the hole is configured to minimize damage to the edges of the hole in subsequent processes to obtain the final diameter of the hole.

[0082] In Figure 8D, operation 860 uses a liquid jet-guided laser beam to form a hole in a substrate, wherein the size of the hole (e.g., diameter) is between 75% and 99% or 80% and 90% of the final diameter of the hole.

[0083] In some embodiments, the liquid jet can be configured to form through-holes or blind holes, wherein the hole size (e.g., the hole diameter) is configured to optimize for high throughput while meeting hole formation requirements (e.g., sidewall roughness values ​​and no edge damage at the hole inlet and outlet). For example, the hole diameter can be greater than 75%, 80%, 85%, or 90% of the final desired diameter, such as between 75% and 99% of the final desired diameter, or between 80% and 99% of the final desired diameter, or between 90% and 99% of the final desired diameter.

[0084] Figures 9A and 9B illustrate the construction of holes formed by liquid jets according to some embodiments. An initial hole 901 can be formed in a substrate 900 using a liquid jet-guided laser 916 (e.g., a liquid jet with an internally reflecting laser beam). The initial hole can be configured for finishing by subsequent smoothing processes (e.g., mechanical rotation processes). For example, the process of forming the initial hole in the substrate is optimized to achieve high throughput, thereby enabling the efficient formation of hundreds or thousands of holes in the substrate.

[0085] Figure 9A illustrates a process in which a liquid jet 916 removes substrate material from one side of a substrate 900 to form an initial via 901. For example, the liquid jet 916 can repeatedly move along a circular profile having a diameter 906 of the initial via in a multi-pass manner. This process continues until the initial via fluidly connects both sides of the substrate. One or more sensors can be positioned on one or both sides of the substrate (e.g., the substrate side opposite the liquid jet guiding laser head) to detect the completion of the via. After observing a sensor detection signal, the liquid jet can continue to pass through the circular profile several more times to ensure that the liquid jet completely penetrates the substrate.

[0086] After the initial hole is formed, the liquid jet can move to other locations on the substrate to form subsequent holes.

[0087] Figures 9B(a) to 9B(c) illustrate another process for forming a through-hole 901 in substrate 900. Because the processing speed typically decreases with increasing depth of cut in liquid jet guided laser processes, it is desirable to process the workpiece from two opposite sides rather than from one side. For example, drilling a hole in 12 mm of material can take more than 180 or 240 seconds. A preferred approach is to first drill a blind hole to a depth of 6 mm, then rotate the workpiece 180° and drill and fluidly connect it to the blind hole on the other side. In this way, the total processing time can be less than 90 seconds or less than 60 seconds.

[0088] Figure 9B(a) illustrates the first step, in which a liquid jet-guided laser 916 rapidly processes at least one blind via 934 in a first surface of substrate 900. The liquid jet 916 can repeatedly pass through and move in a raster pattern within a circular outline with a diameter 906 of the initial blind via 934. The depth of the blind via 934 can be greater than 30% and less than 70% of the thickness of substrate 900, for example, between 40% and 60% of the thickness of substrate 900. After forming the initial blind via, the liquid jet can move to other locations on the substrate to form subsequent blind vias. As shown, the liquid jet has completed the formation of two blind vias on the left side and is forming a third blind via. Then, the liquid jet can move to the right to form subsequent blind vias.

[0089] Figure 9B(b) illustrates the second step, in which the substrate is flipped so that the second surface, opposite the first surface of the substrate 900, faces the liquid jet-guided laser head. For example, using an alignment module, the blind portion of the blind via 934 formed in the first step is aligned such that the central axis of the blind via 934 is aligned with the axis of the liquid jet-guided laser 916. The liquid jet-guided laser 916 is then applied, for example, by turning on the laser source to generate an internally reflected laser beam within the liquid jet, to rapidly process the remaining portion of the blind via 934 and remove all remaining substrate material. As shown, the liquid jet completes the formation of the two vias on the upper left by forming fluid connections to the other portions of the existing blind vias on opposite sides. The liquid jet is forming a third blind via, which is configured to be fluidly connected to the blind vias on opposite sides.

[0090] Figure 9B(c) shows a via 901 formed after the liquid jet has completely removed material from the via in the substrate, fluidly connecting the first and second surfaces of the substrate 900. One or more sensors can be used to detect whether the formation of the via 901 is complete. The liquid jet can then be moved to the right to form a subsequent hole, connecting to an existing blind via on the opposite side.

[0091] In some embodiments, liquid jets can be used to form blind vias, such as holes that do not connect two opposing surfaces of a substrate. Liquid jets can also be used to form two opposing blind vias, such as two opposing holes that are not connected to each other.

[0092] The diameter of the initial hole 901 can be configured to optimize the final hole production rate. For example, for high-volume liquid jet processes using high laser power, the initial hole can be as large as possible to minimize the machining time of the rotary tool. Therefore, the rotary tool can be used to quickly finish the core hole 901 to the desired final hole diameter. Since the liquid jet guided laser 916 has already done all the heavy lifting in terms of material removal, the tool only needs to remove a small portion of the material. For example, for a final hole diameter of 0.45 mm, the initial through-hole diameter can be 0.40 mm, so the tool only needs to remove 0.40 mm to 0.45 mm of substrate material.

[0093] To increase production volume using a slow machining process, two machine tools can be used to simultaneously finish the initial hole 901 to the final hole diameter. For example, the first machine tool can be positioned above a first surface of the substrate. The second machine tool can be positioned below a second surface of the substrate. The central axes of the two machine tools are the same. Both machine tools can maintain a constant distance between them along their central axes. The substrate can be moved up and down along the axes of the two machine tools, or alternatively, both machine tools can be moved up and down along the central axis of the core hole.

[0094] Since mechanical tools typically have a certain material removal rate based on their rotational speed per minute and feed rate perpendicular to the substrate, two mechanical tools can remove more material in a shorter time. Up-and-down oscillation can be required to remove substrate material from the boring hole. Optionally, provided that the movement of the first and second mechanical tools does not collide with the central axis of the boring hole, they can also move independently along the central axis of the core hole 1217 as needed to achieve an efficient removal process.

[0095] Figures 10A to 10C illustrate flowcharts of forming initial holes in a substrate according to some embodiments. In Figure 10A, operation 1000 uses a liquid jet-guided laser beam to form a via in the substrate, wherein the liquid jet-guided laser beam is configured to travel along a closed-loop profile in a multiple-pass manner, and material in the closed-loop profile is removed after the via is formed.

[0096] In Figure 10B, operation 1020 uses a liquid jet to guide a laser beam to form a via in the substrate, wherein the liquid jet guides the laser beam to travel in a grating configuration within a closed-loop profile in a multi-pass manner.

[0097] In Figure 10C, operation 1040 uses a liquid jet to guide a laser beam to form a first blind via in the substrate, wherein the liquid jet-guided laser beam is configured to travel multiple times along a closed-loop profile or within a grating configuration within the closed-loop profile. Operation 1050 optionally flips the substrate to form a second blind via from an opposite surface of the substrate, wherein the second blind via is aligned with the first blind via. The second blind via may connect to the first blind via to form a through-hole through the substrate.

[0098] In some embodiments, the substrate can be heated to increase the throughput of the liquid jet process. Since the liquid jet process is a laser ablation process, such as removing material by laser power, a high-temperature substrate can accelerate the laser ablation process. Additionally, due to the liquid flow, the liquid jet process can rapidly cool the substrate. Therefore, for moving liquid jet cutting, such as material within a circular profile, the substrate can be significantly cooled before the liquid jet returns.

[0099] Figures 11A to 11D illustrate a construction for heating a substrate to accelerate a liquid jet guided laser via forming process, according to some embodiments. A liquid jet guided laser 1116 can be applied to form a hole 1101 in a substrate 1100. When the substrate is thin, for example, less than a few millimeters, the liquid jet guided laser 1116 can cut the hole in a few passes (e.g., less than 15 passes or less than 10 passes). When the substrate is very thick, for example, greater than 5 mm, greater than 10 mm, or greater than 15 mm, significantly more passes are required, for example, greater than 50 passes or greater than 100 passes.

[0100] If the aperture 1101 has a larger shape, such as a large closed-loop profile along which the liquid jet travels to cut a narrow, elongated aperture of several centimeters, then the liquid jet-guided laser 1116 can complete one circumference of the aperture 1101 in just a few seconds. Due to the high velocity of the liquid jet, the strong cooling effect of the process water, and the cooling effect of the coaxial flow of compressed gas, the substrate 1100 can be rapidly cooled after the laser passes through.

[0101] The present invention recognizes that a small amount of liquid jet can be used to guide a laser to cut a small hole circumference 1101 to a certain depth. For a larger hole circumference, for example, a hole circumference 10 times larger at the same depth, two or three times the amount of liquid jet may be required because it takes longer for the liquid jet to guide the laser 1112 to reach the same point on the circumference of the hole 1101 again.

[0102] In some embodiments, an auxiliary heating device can heat the substrate area processed by the liquid jet guided laser 1116 to mitigate the cooling effects on processing time and liquid jet guided laser throughput.

[0103] Figure 11A illustrates a water injection nozzle 1141 for injecting hot water into a workpiece (e.g., substrate 1100). The hot water flow 1141 can be used to accelerate the hole machining process using a liquid jet. During machining using a liquid jet-guided laser 1116, the substrate 1100 can be heated and maintained at a elevated temperature by a heated liquid flow (e.g., water injection nozzle 1141). The water temperature can be greater than 40 degrees Celsius, for example, greater than 50 degrees Celsius. The water temperature can be less than 100 degrees Celsius (e.g., less than 90 degrees Celsius). In some embodiments, other liquids with higher vaporization temperatures can be used to heat the substrate to above 100 degrees Celsius. It may also be required to heat the back side of the substrate instead of the top surface. The water injection nozzle is then mounted below the substrate.

[0104] Figure 11B illustrates an infrared and / or inductive device 1142 that heats and maintains the temperature of substrate 1100 in the processing area to accelerate the via forming process. The substrate temperature can reach 50 degrees Celsius or higher (e.g., 60 degrees Celsius or higher). The substrate temperature can also reach 150 degrees Celsius or lower (e.g., 110 degrees Celsius or lower). It is also possible to heat the back side of the substrate instead of the top surface. The infrared and / or inductive device is then mounted under the substrate.

[0105] Figure 11C illustrates a configuration for heating and maintaining the substrate temperature during liquid jet guided laser processing. The substrate 1100 can be completely 1143 or partially 1144 immersed in an immersion fluid. For example, this immersion fluid can be water or ethanol. The temperature of the immersion fluid can be greater than 40 degrees Celsius (e.g., greater than 50 degrees Celsius). The temperature of the immersion fluid can be lower than the evaporation temperature of the immersion fluid (e.g., water below 100 degrees Celsius or below 110 degrees Celsius).

[0106] Figure 11D illustrates a configuration for heating and maintaining the substrate temperature during liquid jet guided laser processing. The substrate 1100 may receive a gas heating stream, such as an air conditioning device 1145 (e.g., a hot air gun directed at the area of ​​the substrate 1100 being processed). The air conditioning device 1145 can heat the substrate 1100 to a temperature of 40 degrees Celsius or higher (e.g., 50 degrees Celsius or higher). The substrate temperature may be less than 110 degrees Celsius.

[0107] The substrate can be heated to other temperatures (e.g., above 110 degrees Celsius, or below 200 degrees Celsius) to improve the liquid jet cutting process. In some embodiments, the top surface of the substrate, or in addition to the top surface of the substrate, can be further heated to the back surface of the substrate. Then, a gas heating flow is provided from below the substrate, or in addition to the top surface of the substrate.

[0108] In some embodiments, for example, for substrate materials that are easily damaged by heat and are very fragile, a substrate cooling process can be applied to the substrate. For example, the liquid heating nozzle 1141 and the immersion fluid and gas flow nozzle 1145 can be configured to provide cooled or cold liquid or gas. For example, the cooling temperature can be less than 60 degrees Celsius, such as less than 40 degrees Celsius, and can be greater than -10 degrees Celsius.

[0109] Figures 12A to 12D show flowcharts for adjusting substrate temperature during liquid jetting according to some embodiments. In Figure 12A, operation 1200 heats the substrate during operation of the liquid jet-guided laser beam to form holes in the substrate.

[0110] In Figure 12B, operation 1220 maintains the temperature of the substrate between 40 degrees Celsius and 100 degrees Celsius during operation of the liquid jet-guided laser beam.

[0111] In Figure 12C, operation 1240 controls the temperature of the substrate during the operation of the liquid jet-guided laser beam to optimize the processing time for forming holes in the substrate.

[0112] In Figure 12D, operation 1260 places the substrate on a platform below the liquid jet guided laser head. Operation 1270 heats the substrate by using at least one of a liquid flow, a gas flow, an infrared or inductive heating flow, or by fully or partially immersing it in the liquid pool. Operation 1280 operates the liquid jet guided laser head to form one or more holes in the substrate.

[0113] In some embodiments, sensors may be added to detect the progress of the liquid jetting process, particularly to determine the end point of the liquid jetting process. The sensors may be positioned on the opposite side of the liquid jetting head, for example, with a substrate disposed between the liquid jetting head and the sensors.

[0114] When a liquid jet is placed on the top surface of a substrate, a light or optical sensor can be used to detect the presence of the liquid jet on the bottom surface of the substrate. When the light sensor detects the presence of the liquid jet or the laser beam, the signal from the light sensor can indicate that the liquid jet has penetrated the substrate. After the detection signal, the liquid jet can be passed through several more times to ensure the integrity of the cut through the substrate.

[0115] When a liquid jet is placed on the top surface of a substrate, an acoustic or sound sensor can be used to detect the presence of the liquid jet on the bottom surface of the substrate. The sensor can be positioned near the substrate, such as on the side or top of the substrate. As the liquid jet exits the substrate, for example, when the liquid jet has penetrated the substrate, the acoustic or sound sensor can detect a different sound or tone than when the liquid jet is still cutting through the substrate. The tone of the liquid jet can differ when it begins (e.g., without cutting the substrate), when it cuts the substrate, and when it has finished cutting. Therefore, the progress of the liquid jet can be monitored by tracking the tone of the sound emitted by the liquid jet interacting with the substrate.

[0116] Other sensors or combinations of sensors can be used, such as a combination of light and sound sensors.

[0117] Figures 13A to 13C illustrate sensor configurations for detecting the endpoint of a liquid jet guided laser process according to some embodiments. When a hole 1301 is formed in a substrate 1300 using a liquid jet guided laser 1316, a certain material removal rate is applied based on the substrate material and process parameters (e.g., liquid jet nozzle diameter, liquid jet pressure, laser power, laser pulse length, laser frequency, feed rate, and compressed protective gas pressure). Liquid jet guided laser systems are typically capable of drilling hundreds or thousands of holes at the same cutting speed. Therefore, the speed at which the liquid jet cuts through the substrate can be determined from experimental data.

[0118] However, several factors can affect the achievable cutting speed and the time required to fluidly cut through the substrate from its top to its bottom surface. For example, inhomogeneities in the substrate material can cause some areas to cut faster or slower. Furthermore, within the liquid jet-guided laser head, certain components wear down over time, such as the laser window through which the laser must pass before coupling into the liquid jet nozzle. After a certain number of working hours, this laser window is replaced. To expedite the entire drilling or protrusion cutting process and to detect wear on consumable components, sensors that detect the cut point can be applied.

[0119] The cutting optical sensor 1352 may be placed near the substrate 1300. Optionally or additionally, the cutting acoustic sensor 1351 may be placed near the substrate 1300. In some embodiments, both the cutting optical sensor 1352 and the cutting acoustic sensor 1351 are placed beside or below the substrate 1300, wherein at least one hole 1301 is processed by the liquid jet guided laser 1316. When the drilling process begins and the laser beam of the liquid jet guided laser 1316 is turned on, a strong plasma-induced cutting sound can be generated. The pitch frequency of this plasma-induced sound is generally the same as the frequency of the laser beam. As the depth of penetration of the liquid jet guided laser 1312 into the substrate 1300 increases, this plasma-induced sound may decrease or even disappear. During cutting, the sound level emitted by the liquid jet guided laser 1316 rapidly exiting the lower part of the hole 1301 may suddenly increase. In the portions of the hole 1301 that have not yet been cut through, the emitted sound will disappear again. For example, when the liquid jet-guided laser 1316 initially cuts through, only one-quarter of the circumference of the hole 1301 is cut through when the same laser passes through, while three-quarters of the circumference of the hole 1301 remains uncut. For these cut portions, the emitted sound can be detected by the cut acoustic sensor 1351. For the portions of the circumference of the hole 1301 that have not yet been cut through, the cut acoustic sensor 1351 can detect a lower sound or no sound at all.

[0120] When the drilling process begins and the laser beam of the liquid jet-guided laser 1316 is switched on, most of the laser energy is transmitted from the liquid jet-guided laser 1316 through the total internal reflection guide substrate 1300 inside the liquid jet and into the cutting area of ​​the hole 1301. The cutting optical sensor 1352 can be positioned relative to the substrate 1300; in other words, the substrate 1300 is located between the liquid jet-guided laser head and the cutting optical sensor 1352. When the drilling process begins, the cutting optical sensor 1352 can detect low-intensity emitted laser light or no emitted laser light at all. During cutting, the laser level emitted by the liquid jet-guided laser 1316 exiting the lower part of the hole 1301 may suddenly increase. In the portion of the hole 1301 that has not yet been cut through, the emitted laser light will disappear again. For example, during the initial cutting of the liquid jet-guided laser 1316, only one-quarter of the circumference of the aperture 1301 is cut through when the same laser passes through, while three-quarters of the circumference of the aperture 1301 remains uncut. For this cut portion, the emitted laser can be detected by the cutting optical sensor 1352. For the portion of the circumference of the aperture 1301 that has not yet been cut through, the cutting optical sensor 1352 can detect even lower-level lasers or no lasers emitted at all.

[0121] In some embodiments, within the liquid jet-guided laser head, light from a source other than that generated by the laser itself is coupled into the liquid jet-guided laser 1316. This secondary light source can be an LED emitting a specific wavelength. The cutting optical sensor 1352 can be equipped with at least one optical filter that blocks the laser wavelength while allowing the LED wavelength to pass through, and vice versa. During cutting, the LED illumination suddenly increases under the guidance of the liquid jet-guided laser 1316 at the lower part of the exit hole 1301. The LED illumination disappears again in the portion of the hole 1301 that has not yet been cut through. For example, during the initial cutting of the liquid jet-guided laser 1316, only one-quarter of the circumference of the hole 1301 is cut through when the same laser passes through, while three-quarters of the circumference of the hole 1301 remains uncut. The LED illumination can be detected by the cutting optical sensor 1352 for this cut portion. For the portion of the circumference of hole 1301 that has not yet been cut through, the cutting optical sensor 1352 can detect even lower LED light or no LED light at all.

[0122] Figure 13C illustrates the amplitude behavior of the cutting optical sensor, the cutting acoustic sensor, and the emitted laser. The moment the liquid jet-guided laser 1316 cuts through the substrate 1300 can be accurately determined using either the cutting optical sensor 1352 or the cutting acoustic sensor 1351. In addition to determining the moment of cutting, the completely cut hole on the circumference can be further detected. In this case, the emitted laser intensity 1352* detected by the cutting optical sensor 1352 remains at a high intensity throughout the entire processing of the liquid jet-guided laser 1316 on the circumference of the hole 1301, or the emitted sound intensity 1351* detected by the cutting acoustic sensor 1351 remains at a high intensity throughout the entire processing of the liquid jet-guided laser 1316 on the circumference of the hole 1301. In some embodiments, the cutting point of the aperture 1301 formed by the liquid jet-guided laser 1316 is detected by a combination of the cutting optical sensor 1352 and the cutting acoustic sensor 1351. The emitted laser intensity 1352* and the emitted sound intensity 1351* can be monitored in the laser on / off mode 1311*.

[0123] Before the hole 1301 is fabricated in the substrate 1300, the laser emission of the liquid jet guiding laser head is turned off. Typically, the laser emission and the water source forming the liquid column can be controlled independently. For example, water can be circulated when the laser emission is off. When the hole 1301 fabrication process begins, the laser emission is turned on and guided through the liquid jet onto the substrate 1300. At the instant the laser is turned on 1353, the detected emitted laser intensity 1352* may be below the signal threshold because the uncut substrate 1300 forms an optical barrier, and no laser can be received by the cutting optical sensor 1352. At the instant the laser is turned on 1353, the detected emitted sound intensity 1355 may be above the signal threshold because the cutting acoustic sensor 1351 can detect the sound emitted by the cutting plasma. However, once the liquid jet-guided laser 1316 penetrates deeper into the substrate 1300, the emitted sound intensity 1353 can quickly decrease below the signal threshold.

[0124] At the instant of laser cutting 1354, both the emitted laser intensity 1356 and the emitted sound intensity 1357 can rapidly increase and exceed the signal threshold. Throughout the entire circumference of the hole 1301, the liquid-jet guided laser can remain open and process until the emitted laser intensity 1356 and the emitted sound intensity 1357 remain above the signal threshold. Then, the laser can be switched off, and at the instant of laser shutdown 1354*, both the emitted laser intensity 1356 and the emitted sound intensity 1357 can suddenly drop below the signal threshold again. Monitoring the emitted laser intensity 1352* and the emitted sound intensity 1351* provides a safe method to detect complete cutting of the hole 1301 in various substrates and substrate 1300 materials, as well as different hole geometries (e.g., circular holes, square holes, elliptical holes, elongated holes, tapered holes, narrow high aspect ratio lines, and other freeform shapes).

[0125] Figures 14A and 14B illustrate flowcharts for detecting the endpoint of a liquid jet process according to some embodiments. In Figure 14A, operation 1400 activates laser emission to generate a laser beam that is internally reflected in the liquid column to form an aperture through the substrate. Operation 1410 receives a signal from at least one of an optical sensor and an acoustic sensor indicating that the aperture has completely passed through the substrate. Operation 1420 deactivates laser emission.

[0126] In Figure 14B, operation 1440 senses the passage of a liquid column having an internally reflected laser beam generated above the substrate, wherein the sensing includes receiving signals from a photosensitive sensor and an acoustic sensor. Operation 1450 allows the liquid column having the internally reflected laser beam to travel for a predetermined amount of time. Operation 1460 shuts off laser emission.

[0127] In some embodiments, an initial via can be formed in a substrate using an electrical discharge machining (EDM) process. For example, an EDM process can be used to enlarge an initial via formed by a liquid jet. Alternatively, an EDM process can be used to form an initial via without a liquid jet.

[0128] Figures 15A to 15D illustrate a process for forming an initial hole using liquid jet and electrical discharge machining according to some embodiments. Figure 15A shows the formation of an initial hole 1501 in a substrate 1500 using a liquid jet 1516. The diameter of the initial hole 1501 can be configured to accommodate an EDM electrode, such as a wire 1507 connecting two terminals of an EDM power supply 1535.

[0129] Figure 15B illustrates hole enlargement using a wire EDM process. For example, after enlarging the hole to a size slightly smaller than the final diameter, a mechanical rotary tool can be used to finish the enlarged hole, such as smoothing the surface of the enlarged hole. Compared to the EDM process, mechanical rotary tools can provide a lower surface roughness value.

[0130] EDM processes can be wire-based EDM processes, in which fine wires are used to etch material within the diameter of the hole 1501. In this case, the EDM electrode diameter 1508 is much smaller than the core hole diameter 1501, and a circular machining motion can be performed to cut a cylindrical pin. Alternatively, the EDM process can perform a helical motion or a combination of circular and helical machining motions to remove all material within the diameter of the hole 1501.

[0131] For example, the wire can pass through a hole formed by a liquid jet and connected to a terminal of the EDM power supply. The substrate 1500 can be connected to a second terminal of the EDM power supply. When the EDM power supply is turned on, the substrate material can be removed, for example, by a discharge process from the wire EDM to the substrate. The wire can move within a closed loop profile (e.g., a circular profile) to enlarge the initial hole to the desired size.

[0132] Figure 15C illustrates a hole-enlarging process using a submerged electrode-based EDM process, in which a hole-shaped electrode is used to etch material within the diameter of hole 1501. For example, after enlarging the hole to a size slightly smaller than the final diameter, a mechanical rotary tool can be used to finish the enlarged hole, for example, by smoothing the surface of the enlarged hole. The EDM electrode can be coupled to an EDM power source at one end. In this case, the EDM electrode 1507* can be only slightly smaller than the initial hole formed by the liquid jet.

[0133] Figure 15D illustrates the construction of a hole formed by an EDM process for expanding the initial hole created by the liquid jet. The diameter 1508 of the EDM hole can be slightly smaller than the final diameter 1502. The EDM hole can be finished using machine tools to achieve the desired final hole with a final diameter 1502, where the final diameter 1502 has the desired quality and surface roughness values.

[0134] Figures 16A and 16B illustrate a process for forming an initial hole using electrical discharge machining (EDM) according to some embodiments. In Figure 16A, the EDM process can be a dip electrode-based EDM process, in which an electrode 1607 is applied to a substrate to etch material in the substrate. The electrode is connected to a terminal of an EDM power supply 1635. The substrate is connected to another terminal of the EDM power supply.

[0135] Figure 16B shows the construction of an initial hole formed by an EDM process. The diameter 1608 of the EDM hole can be slightly smaller than the final diameter 1602. The EDM hole can be finished using machine tools to achieve the desired final hole with a final diameter of 1602, where the final diameter 1602 has the desired quality and surface roughness values.

[0136] Figures 17A to 17C illustrate flowcharts of forming holes using EDM processes according to some embodiments. In Figure 17A, operation 1700 uses a liquid jet-guided laser beam to form a hole through the substrate. Operation 1710 uses wire electrical discharge machining to enlarge the hole. Operation 1720 uses a mechanical rotary tool to smooth the enlarged hole.

[0137] In Figure 17B, operation 1740 uses electrical discharge machining to form a hole in the substrate. Operation 1750 uses a mechanical rotary tool to smooth the hole.

[0138] In Figure 17C, operation 1770 uses a liquid jet-guided laser beam or electrical discharge machining to form a hole in the substrate. Operation 1780 uses a mechanical rotary tool to smooth the hole.

[0139] In some embodiments, the liquid jet can be moved from one location to another on a substrate to form a plurality of initial holes, and then the substrate is transferred to a mechanical rotary tool head to finish these holes. The movement of the liquid jet can be performed by a motion mechanism (e.g., an xy or xyz motion stage) to guide the laser head to move, thereby generating the liquid jet.

[0140] Figures 18A and 18B illustrate structures for forming multiple holes in a substrate using a liquid jet according to some embodiments. Figures 18A(a) and 18A(b) illustrate a structure for forming a through-hole in a substrate from one side using a liquid jet. Figures 18B(a) and 18B(b) illustrate a structure in which a blind hole is formed in a substrate from one side using a liquid jet, the substrate is then flipped, and the blind hole is processed into a through-hole from the opposite side of the substrate.

[0141] In Figure 18A(a), a liquid jet 1816 (e.g., a liquid jet having an internally reflected laser beam generated by a laser head constrained within the boundaries of the liquid jet and guided by the liquid jet) can be used to form a via 1801 in the substrate 1800. The liquid jet can pass through multiple times along a closed-loop profile (e.g., along a circular profile) to cut a cylinder with a diameter the same as the desired hole diameter. Alternatively, the liquid jet can be rasterized within the circular profile, for example, by creating a spiral path or multiple parallel lines, to remove material from the hole instead of creating a cylinder. In Figure 18A(b), the liquid jet moves to another location on the substrate to form a subsequent via.

[0142] The vias in the substrate can be initial holes, for example, vias that are subsequently finished by a mechanical rotary tool, for example, to make the hole walls smooth.

[0143] In some embodiments, the initial aperture can be formed by a combination of liquid jetting and EDM processes. For example, liquid jetting can form one or more initial apertures having a diameter suitable for an EDM electrode. For example, using a submerged electrode-based EDM process, the initial aperture formed by liquid jetting can be slightly larger than the submerged electrode size. If a wire electrode-based EDM process is used, the initial aperture can be even larger, for example, large enough to allow a wire to pass through. Alternatively, the aperture can be formed by an EDM process without an initial aperture. For example, a submerged electrode can be placed near the substrate, and the EDM power can be turned on to remove material from the electrode to form the aperture.

[0144] In any case, the size of the initial hole formed by the liquid jet, the combination of the liquid jet and the EDM electrode, or the EDM electrode can be suitable for subsequent finishing processes using mechanical rotary tools.

[0145] In some embodiments, a liquid jet can form all vias in a substrate. The substrate can then be moved to an EDM system, which can be configured to further process the vias formed by the liquid jet. After finishing, the substrate can be moved to a mechanical rotary system, where a mechanical rotary tool can be used to complete the processing of the initial holes.

[0146] In Figure 18B(a), a liquid jet 1816 can be used to form a blind via 1834 in a substrate 1800. The liquid jet can form a blind via at one location on the substrate. The liquid jet then moves to another location to form another blind via. This process continues until all blind vias are formed in the substrate.

[0147] In Figure 18B(b), the substrate is flipped, for example, so that the opening side of the blind via is now located on the opposite side of the liquid jet. For example, the liquid jet can be aligned with the blind via by an alignment module. After alignment, the liquid jet can form another blind via on the opposite side of the aligned blind via. The liquid jet can be further processed to connect the two blind vias to form a through-hole, thereby connecting the two sides of the substrate.

[0148] After forming a through-hole, by connecting a blind via to an existing opposite blind via, the liquid jet can move to another location on the substrate to form a subsequent through-hole.

[0149] The vias in the substrate can be initial holes, for example, vias that are subsequently finished by a mechanical rotary tool, for example, to make the walls of the holes smooth.

[0150] Figure 19 illustrates a closed-loop process for drilling holes using a liquid jet-guided laser according to some embodiments. A laser machining process for drilling or boring core holes can be enabled. The laser machine tool can move the liquid jet-guided laser head to a first position among multiple machining positions. The laser process can be initiated. Once at least one sensor detects a cut-through signal, the laser process can perform additional safety passes a predetermined number of times. After the predetermined number of safety passes, the laser process can stop, and the laser machine tool moves the liquid jet-guided laser head to the next machining position among multiple machining positions. The cycle continues, and the cycle is completed once the last of the multiple machining positions is reached.

[0151] Operation 1900: The substrate is placed on the platform. The nozzle of the liquid jet guiding laser head can be used to form a liquid jet. The nozzle can also be aligned with the laser beam to obtain an internally reflected laser beam within the liquid jet. Operation 1910: The liquid supply is turned on to form a liquid column. Operation 1920: The liquid jet guiding laser head is moved to a first position on the substrate. Operation 1930: Laser emission is turned on to generate an internally reflected laser beam in the liquid column for forming a first hole through the substrate. Operation 1940: Optional additional laser pass-through is performed to ensure that the substrate is cut through after a cut-through signal from the sensor is observed. Operation 1950: Laser emission is turned off. Operation 1960: Subsequent cut-through holes are formed at subsequent positions.

[0152] In some embodiments, the present invention discloses a subsequent process for finishing an initial hole formed by a liquid jet-guided laser system, for example, smoothing the sidewalls of the initial hole and achieving the desired final diameter of the hole, while ensuring that the inlet and outlet edges are undamaged. The finishing process can be performed by a mechanical rotary tool (e.g., a drill bit, side-milling bit, end-milling bit, reamer, or honing tool) that can smooth the sidewalls of the initial hole. Using a rotary tool with a diameter equal to the final hole diameter, the rotary tool can further adjust the initial hole to have the final diameter while smoothing the sidewalls. Furthermore, using a rotary tool with a rounded tip (e.g., an elliptical tip) can further avoid sudden starting contact between the rotary tool and the surface at the hole inlet, thus allowing the edge of the hole inlet to be adjusted to be sharp without wear, such as edge chipping or unevenness. In some embodiments, the substrate can be flipped, and the rotary tool can form a sharp edge (e.g., an undamaged edge) at the other end of the through-hole (e.g., the hole outlet).

[0153] Mechanical rotary processes can include cutting, honing, or grinding processes. A cutting process may include one or more sharp edges on a cutting tool for cutting material from a substrate. For example, a drill bit may have a tapered cutting edge at its tip for axial material removal. A drill bit may have sharp cutting edges at its grooved portion for removing material from the sidewalls of a drilled hole. A honing process may include one or more roughened surfaces on a honing tool for removing material from a substrate by the honing process.

[0154] Mechanical rotary processes can include drilling, boring, reaming, milling, or honing. Drilling is a cutting process that uses a drill bit to cut a circular hole in a substrate. A mechanical rotary tool (e.g., a drill bit) can be used to cut material during drilling. Drilling can be performed with or without an initial hole. With an initial hole, the drill bit can rotate while subsequently scraping material from the sidewalls of the initial hole. Without an initial hole, the drill bit can drill into the substrate to form a circular hole. A mechanical rotary head can be used to hold and rotate the rotary tool.

[0155] Boring is also a cutting process that uses a single-point cutting tool, a boring head, or a boring bar to enlarge existing holes in a substrate. The boring process is similar to drilling with an existing hole, used to enlarge and smooth the existing hole in the substrate. The boring process differs from drilling without an initial hole, used to create an initial hole in the substrate.

[0156] Reaming is also a cutting process that uses rotary cutting or honing tools (e.g., reamers or reaming drills) to form smooth inner walls in existing holes in a substrate. Like drills and boring bars, reamers remove sidewall material from the initial hole. However, compared to drills, reamers remove significantly less material, for example, at a slower rate. Reamers are typically used to form smooth walls in initial holes.

[0157] Honing is a grinding process that uses a honing stone or honing tool to create a precision surface on a metal workpiece by grinding a honing stone or wheel. Honing tools may include a diamond abrasive boring bar. The tool can be extended to compensate for wear of the diamond sleeve.

[0158] In some embodiments, the rotary tool can be selected based on the purpose of the work. For example, a drill bit can be used to quickly enlarge an initial hole with a rough sidewall surface. A boring bar is more precise and can produce a smoother sidewall surface. Of the three types of rotary cutting or honing tools, reamers and honing tools are more precise and can also produce the smoothest surface.

[0159] Figures 20A and 20B illustrate a process for forming holes according to some embodiments. Figures 20A(a) to 20A(c) show a process using a mechanical rotary tool without initial holes. For example, without initial holes, precision holes 2001 in a ceramic substrate 2000 for a gas distribution plate or homogenization plate can be formed by sequentially drilling each hole 2001 using a mechanical rotary tool 2020 (e.g., a drill bit). A typical substrate 2000 of a gas distribution plate or homogenization plate is made of monocrystalline silicon and can have 1,000 to 2,000 high aspect ratio precision holes 2001 to create fluid connection between the front and rear sides of the substrate. The diameter of the precision holes 2001 is 0.2 mm to 0.8 mm, and the hole depth is up to 10 mm to 15 mm. To achieve the desired hole diameter, rotary tools with the same diameter are typically used. The requirements for the holes in the gas distribution plate or uniformity plate may include making the inner wall of each hole smooth, like a mirror, to avoid the adhesion of unwanted particles that may potentially contaminate the actual product wafer, through which the gas 2001 is guided to the actual product wafer.

[0160] Drilling tools 2020 typically achieve the desired mirror-like surface finish on the inner walls of holes. To ensure a stable and repeatable gas distribution, the hole inlet and outlet must further have sharp edges without any circumferential damage. Since the substrate 2000 can be a fragile substrate (e.g., monocrystalline silicon), mechanical drilling tools can increase the risk of material breakage 2061 at the hole inlet and 2062 at the hole outlet.

[0161] Furthermore, when processing ceramic substrates 2000, such as materials like silicon or silicon carbide, there is substantial wear on the drilling tools, resulting in shortened tool life. In terms of production volume, each hole 2001 may take 3 to 4 minutes to drill. For example, if the drill bit breaks at the 1480th hole in a substrate requiring 1500 holes, the entire substrate 2000 may potentially be scrapped, and many hours of machining work will be lost.

[0162] Figures 20B(a) to 20B(c) illustrate the process using a mechanical rotary tool 2020* with an initial hole. An initial hole 2001 can be formed in a substrate 2000. The diameter of the initial hole can be slightly smaller than the diameter of the final hole; for example, the initial diameter can be between 75% and 99% of the final diameter. Alternatively, the difference between the final diameter and the initial diameter can be several times the surface roughness of the initial hole (e.g., 2 to 10 times, 2 to 6 times, or 2 to 4 times). Therefore, the rotary tool can smooth the sidewall surfaces from the initial hole to the final hole without significantly removing sidewall material.

[0163] The rotary tool 2020* may have a tool tip 2023, for example, a tip that allows the rotary tool to contact the top edge from the sidewall surface, for example, at an angle not perpendicular to the top surface of the substrate (this can reduce potential material breakage at the top edge). Therefore, with minimal material removal from the tool tip, especially at the top edge, the top edge of the hole can be free of irregularities, such as breakage or damage 2061*. The rotary tool can continue, thus allowing passage through the hole from the top direction.

[0164] In some embodiments, the substrate 2066 can be flipped. For example, before completing the through-hole, the rotary tool 2020* is removed from the substrate, and the substrate is flipped so that the bottom surface of the substrate faces the rotary tool. The rotary tool can then rotate and move downward to finish the hole from a new side (e.g., from the bottom side to the top side). With the tool tip present, the bottom edge can be free of chipped edges or damage 2062*.

[0165] Figures 21A to 21C illustrate configurations of mechanical rotary tools according to some embodiments. Mechanical rotary tools can be used to finish holes formed by liquid jet processing, a combination of liquid jet processing and EDM processes, or by EDM processes. To remove residual material between the core hole and the final hole diameter, the mechanical tool can rotate at a speed greater than 20,000 RPM. In some embodiments, the mechanical tool can rotate at speeds between 40,000 and 120,000 RPM (revolutions per minute).

[0166] Based on the substrate material, the mechanical rotary tool 2120 used to finish the core hole to the final hole diameter can have different shapes to achieve optimal material removal, desired hole inner wall surface finishing, and tool life. The mechanical rotary tool can be a drill bit, reamer, milling tool, or honing tool.

[0167] Figures 21A(a) to 21A(c) illustrate different tool tips for rotary tools, which may have tip parameters optimized for mandrel finishing processes. The tool tip 2163 or 2163* of the machine tool 2120 may be a flat tip, or it may have a tip optimized to allow the tool to softly self-center along the central axis of the mandrel. The tool tip may have a conical shape, a hemispherical shape, or another suitable convex shape.

[0168] Figures 21B(a) to 21B(c) illustrate different configurations for a rotary tool body, for example, having a primary cutting surface 2164 and a secondary cutting (or non-cutting) surface 2164*. The primary cutting surface 2164 of the tool can be made of carbide, hard metal, boron carbide, silicon nitride, or cubic boron nitride. In some embodiments, the primary cutting surface of the tool can be made of a diamond material (e.g., a synthetic diamond material). Examples of such synthetic diamond materials are polycrystalline diamond (PCD), single-crystal diamond (or single-crystal diamond SCD), or diamond particles in a binder material.

[0169] In some embodiments, the rotary tool may have a primary cutting surface 2164 made of diamond material, which is connected to a secondary cutting or non-cutting surface 2164* made of different materials (e.g., carbide, hard metal, boron carbide, silicon nitride, or cubic boron nitride).

[0170] In some embodiments, the rotary tool may have a primary cutting surface 2164 made of diamond material, wherein the primary cutting surface extends upward to the tool axis.

[0171] Figures 21C(a) to 21C(c) illustrate different tool shaft configurations for rotary tools. Typically, a rotary tool can have the same diameter across both the primary and secondary cutting surfaces. In some embodiments, the rotary tool can have a second tool diameter to optimize different parameters of the core hole finishing process. For example, a rotary tool can have a primary tool cutting surface with a first tool diameter connected to a secondary tool cutting surface with a second tool diameter (e.g., recess diameter 2165).

[0172] Figures 22A to 22C illustrate flowcharts for finishing holes in a substrate according to some embodiments. In Figure 22A, operation 2200 uses a mechanical rotary tool to smooth the holes in the substrate. In Figure 22B, operation 2220 rotates the mechanical rotary tool as it enters the holes in the substrate, wherein the holes have a diameter optimized for high throughput and minimal edge damage.

[0173] In Figure 22C, operation 2240 rotates a mechanical rotary tool when entering a hole in the substrate. The mechanical rotary tool may have a rounded tip. The mechanical rotary tool may have a portion near the tip configured to smooth the inner surface of the hole. The mechanical rotary tool may have a portion near the base whose diameter is smaller than the diameter of the portion near the tip of the mechanical rotary tool.

[0174] In some embodiments, the gas distribution plate or homogenization plate can be formed by a combination of liquid jet processing and mechanical rotation processing. For example, a core hole can be initially formed using a liquid jet-guided laser, and then the core hole can be finished to a final hole using a mechanical rotation tool. Liquid jet-guided lasers can be used to quickly drill deep and high-quality micro-holes without any tool wear. To form a core hole in a substrate, a liquid jet-guided laser can perform circular machining motions and cut out cylindrical pins, or a liquid jet-guided laser can make helical or a combination of circular and helical machining motions to remove all material inside the diameter of the core hole.

[0175] The surface roughness of the hole sidewalls can be achieved to values ​​below Ra 1 μm, or even below Ra 0.3 μm. However, workpieces (e.g., substrates for gas distribution and homogenization plates used in semiconductor processing equipment) may require hole sidewall roughness values ​​below Ra 0.1 μm. Mechanical drilling tools can achieve such roughness values ​​below Ra 0.1 μm; however, the drilling process is slow because the drill needs to slowly enter and exit the substrate material to avoid damaging the hole inlet and outlet in the form of broken substrate material. Such a drilling process can take 3 to 5 minutes to make only one hole. Furthermore, the drilling tool may wear out as quickly as after only a few hundred holes.

[0176] In some embodiments, liquid jet-guided lasers are used to rapidly remove most of the material from the hole, and the liquid jet-guided laser performs all the heavy lifting in material removal quickly without any tool wear. Liquid jet-guided lasers can be used to rapidly form core holes with a diameter slightly smaller than the desired final hole diameter. For example, if the desired final hole diameter in an 11 mm thick silicon substrate is 0.45 mm, a liquid jet-guided laser can be used to rapidly form a 0.40 mm diameter core hole. Depending on the liquid jet-guided laser parameters, such core holes can be formed, for example, in 30 to 60 seconds.

[0177] After the hole is formed, a mechanical tool can be used to remove a small amount of remaining material. A tool with a diameter matching the final hole diameter can extend the core hole diameter to the final hole diameter while removing only a very small amount of material. Therefore, the feed rate of the mechanical tool along the central axis of the core hole can be significantly faster compared to drilling a final hole through the entire bulk substrate material. This finishing step can be completed, for example, in 30 to 60 seconds, reducing the total time for drilling the desired hole diameter with the desired quality and surface finish by 50% or more.

[0178] In some embodiments, depending on the optimal material flow and cycle time in the production facility, the operation of forming core holes by liquid jet guiding laser and finishing the core holes to the final hole diameter by mechanical tools can be applied in the same machine (liquid jet guided laser + mechanical drilling rig) or in two separate machines.

[0179] In some embodiments, the initial aperture may be formed by an EDM process (e.g., a combination of liquid jetting and EDM processes) or by EDM processes alone. For example, a wire-based electrode EDM process may be used in conjunction with a liquid jetting process to form the initial aperture. Alternatively, in the absence of a liquid jetting process, a submerged electrode-based EDM process may be used to form the initial aperture.

[0180] After the initial hole is formed by liquid jetting, EDM, or a combination of liquid jetting and EDM, the initial hole can be finished by a mechanical rotary tool, for example, smoothed to the final size, to obtain a final hole with the desired diameter and desired quality and roughness values.

[0181] In some embodiments, a mechanical rotary tool can be configured to smooth the initial hole from one side, sequentially from two sides, or simultaneously from two sides. Alternatively, the initial through-hole can be formed by a liquid jet from one side or from two sides.

[0182] In some embodiments, the hole finishing process can be optimized based on the initial hole formation, the substrate material, and further, the final hole requirements. To achieve the best hole, sidewall quality and inlet and outlet side quality must be considered for different core hole finishing strategies. For example, a core hole can fluidly connect an upper side of the substrate to a lower side. Mechanical tools can be applied to finish the core hole to the desired final hole diameter. The mechanical tools can have a tool diameter equal to or slightly smaller than the desired final hole diameter.

[0183] In some embodiments, the through-hole may be a blind via covering more than 30% of the substrate depth (e.g., more than 50% but less than 95% of the substrate depth). A machine tool can be applied to finish the through-hole to the desired final hole diameter. The machine tool may enter the substrate from the opening side of the through-hole. The machine tool may create a final protrusion through the lower side of the substrate. The machine tool may have a tool diameter equal to or slightly smaller than the desired final hole diameter.

[0184] In some embodiments, the core via may be a blind via covering more than 30% of the substrate depth (e.g., more than 50% but less than 95% of the substrate depth). A machine tool may enter the substrate from the blind side of the core via and drill through all the material until it reaches the opening portion of the core via. The machine tool may then be applied to finish the core via to the desired final hole diameter. The machine tool may have a tool diameter equal to or slightly smaller than the desired final hole diameter.

[0185] In some embodiments, a core via may consist of two blind vias, each located on opposite sides of the substrate, wherein the central axis of each core via is substantially on the same axis passing through the substrate. Each of the two blind vias may cover more than 30% but less than 45% of the substrate depth. A mechanical tool may enter the substrate from the open side of either core via. The mechanical tool may create a final protrusion through the central portion of the substrate. The mechanical tool may have a tool diameter equal to or slightly smaller than the desired final hole diameter. This method may be preferred for very fragile substrate materials that are sensitive to material breakage when the mechanical tool enters either side of the substrate surface. The critical protrusion is formed on the inner side of the substrate where the risk of material breakage is low.

[0186] Figures 23A and 23B illustrate a process for finishing an initial through-hole according to some embodiments. Figures 23A(a) to 23A(c) show a rotary tool 2320 approaching a through-hole 2301 in a substrate 2300. The through-hole 2301 may be formed by a liquid jet process, and its diameter is slightly smaller than the diameter of the rotary tool 2320. The rotary tool can rotate and enter the initial through-hole 2301 to smooth the sidewalls of the initial through-hole and also to give the initial through-hole a final diameter. The rotary tool can be withdrawn from the substrate, for example, to move to another through-hole.

[0187] Figures 23B(a) to 23B(e) illustrate another process where a rotary tool 2320 finishes or smooths an initial via in a substrate. The rotary tool can smooth a portion of the via from a first side of the substrate. The rotary tool can then be withdrawn from the substrate. The substrate 2366 can then be flipped. The rotary tool can then smooth the remaining portion of the via from a second side of the substrate opposite to the first side. The rotary tool can then be withdrawn from the substrate.

[0188] Figures 24A to 24C illustrate a process for finishing an initial single-sided blind via according to some embodiments. Figures 24A(a) to 24A(b) show a rotary tool 2420 approaching a blind via 2434 from the opening side of the blind via. The blind via 2434 can be formed in the substrate 2400 by a liquid jet process, and its diameter is slightly smaller than the diameter of the rotary tool 2420. The rotary tool can rotate and enter the initial blind via 2434 to smooth the sidewalls of the initial blind via and also to give the initial blind via a final diameter. The rotary tool can be withdrawn from the substrate, for example, to move to another blind via.

[0189] Figure 24B illustrates another process for finishing blind vias, in which a rotary tool 2420 approaches a blind via 2434 from the blind side (e.g., from the opposite side of the opening). The blind via 2434 can be formed in a substrate 2400 by a liquid jet process, and its diameter is slightly smaller than that of the rotary tool 2420. The substrate can then be flipped to expose the blind side of the blind via to the rotary tool. The rotary tool can rotate and cut into the substrate from an aligned position, which is the center of the blind via. The rotary tool can then form a final through-hole, thereby smoothing the sidewalls of the hole and further contributing to giving the initial hole a final diameter. The rotary tool can be withdrawn from the substrate, for example, to move to another blind via.

[0190] Figures 24C(a) to 24C(e) illustrate another process where a rotary tool 2420 finishes or smooths an initial blind via in a substrate. The rotary tool can smooth a portion of the blind via from the opening side. The rotary tool can then be withdrawn from the substrate. The substrate 2466 can then be flipped. The rotary tool can smooth the remaining portion of the blind via from a second side of the substrate opposite to the opening side. The rotary tool can then be withdrawn from the substrate.

[0191] Alternatively, the rotating tool can first smooth a portion of the blind hole from the opposite side of the opening side.

[0192] Figures 25A and 25B illustrate a process for finishing an initial double-sided blind via according to some embodiments. Figures 25A(a) to 25A(c) show a rotary tool 2520 approaching a blind via 2534 from either of its two open sides. The blind via 2534 may be formed in the substrate 2500 by a liquid jet process, and its diameter is slightly smaller than that of the rotary tool 2520. The rotary tool can rotate and enter the initial blind via 2534 to smooth the sidewalls of the initial blind via and also to give the initial blind via a final diameter. The rotary tool can be withdrawn from the substrate, for example, to move to another blind via.

[0193] Figures 25B(a) to 25B(e) illustrate another process where a rotary tool 2520 finishes or smooths an initial blind via in a substrate. The rotary tool can smooth a portion of the blind via from either of its two open sides. The rotary tool can then be withdrawn from the substrate. The substrate 2566 can then be flipped. The rotary tool can then smooth the remaining portion of the blind via from a second side of the substrate opposite to the open side of the through-hole. The rotary tool can then be withdrawn from the substrate.

[0194] In some embodiments, two mechanical tools can be used to simultaneously finish the core hole to the final hole diameter. The first mechanical tool can be positioned above a first surface of the substrate. The second mechanical tool can be positioned below a second surface of the substrate. The central axes of the two mechanical tools are the same. Both mechanical tools can maintain a constant distance from each other along their central axes. The substrate can move along the axes of the two mechanical tools in a tumbling motion, or alternatively, both mechanical tools can move simultaneously along the central axis of the core hole in a tumbling motion. Since the mechanical tools typically have a material removal rate based on their rotational speed per minute and feed rate in a direction perpendicular to the substrate, the two mechanical tools can remove more material in a shorter time. Tumbling motion from the hole may be necessary to remove substrate material. Alternatively, the first and second mechanical tools can also move independently of each other along the central axis of the core hole as needed for an efficient removal process, provided that their movement does not collide on the central axis of the core hole.

[0195] Figures 26A and 26B illustrate a process for finishing a hole using two mechanical rotary tools according to some embodiments. Figures 26A(a) and 26A(d) show two opposite sides of two rotary tools 2620 and 2620* facing a through-hole 2601 in a substrate 2600. The through-hole 2601 can be formed by a liquid jet process, and its diameter is slightly smaller than the diameter of the rotary tools 2620. The rotary tools can rotate and enter the initial through-hole 2601 to smooth the sidewalls of the initial through-hole and also to give the initial through-hole a final diameter. The rotary tools can move independently or simultaneously. For example, the two rotary tools can swing back and forth from the substrate. The distance between the two rotary tools can be constant, for example, the two rotary tools swing while maintaining a constant distance apart. The distance between the two rotary tools can vary, for example, the distance can vary from very close to each other to very far apart. The rotary tools can be withdrawn from the substrate, for example, to move to another through-hole.

[0196] Figures 26B(a) to 26B(d) show two rotating tools 2620 and 2620* facing two opposite sides of the double-sided blind via 2634 in the substrate 2600. The rotating tools can be rotated and enter the initial blind via 2601 to smooth the sidewalls of the initial blind via and also to give the initial blind via a final diameter.

[0197] Figures 27A to 27C illustrate flowcharts for finishing initial holes in a substrate according to some embodiments. In Figure 27A, operation 2700 rotates a mechanical rotating tool as it enters a through-hole in the substrate. The mechanical rotating tool enters the through-hole from a first side to completely smooth the surface of the through-hole. Alternatively, the mechanical rotating tool enters the through-hole from the first side to smooth a portion of the surface of the through-hole, and then enters the through-hole from a second, opposite side to smooth the surface of the remaining portion of the through-hole.

[0198] In Figure 27B, operation 2720 involves rotating the mechanical rotating tool as it enters a blind via in the substrate. The mechanical rotating tool enters the blind via from a first side to completely smooth the surface of the via. Alternatively, the mechanical rotating tool enters the blind via from the first side to smooth a portion of the surface of the via, and then enters the blind via from a second, opposite side to smooth the surface of the remaining portion of the blind via.

[0199] In Figure 27C, operation 2740 involves rotating two mechanical rotating tools as they enter holes in the substrate. The mechanical rotating tools enter the holes independently of each other. Alternatively, the mechanical rotating tools may simultaneously enter blind holes in opposite directions, and then be moved in one direction while maintaining a constant distance between the mechanical rotating tools.

[0200] In some embodiments, the temperature of the mechanical rotating tool can be adjusted (e.g., regulated) to prevent overheating caused by the rotating motion of removing material from the sidewalls of holes in the substrate. Furthermore, the mechanical rotating tool can be subjected to a lubricant, for example, to prevent excessive wear and tear on the rotating tool. Liquid or gas flows or immersion baths can be used to maintain a constant temperature for the rotating tool, for example, to cool the rotating tool to ambient temperature.

[0201] Machine tools can be actively cooled before, during, and after the material removal process. Active cooling can be achieved using a cooling fluid (e.g., water) or a gas (e.g., air or CO2). The cooling medium can be supplied to the machine tool externally as an axial, radial, or angular flow.

[0202] In some embodiments, the machine tool may have an internal cooling channel through which a cooling medium can be guided and sprayed onto the primary and secondary cutting surfaces of the tool via an outlet port facing the tool tip.

[0203] In an alternative configuration, the machine tool has a coaxial center hole that fluidly connects the upper portion of the tool to the tool tip. Due to the long working length, a liquid-jet guided laser can be guided through the center hole in the machine tool. In the first step, the liquid-jet guided laser is applied to remove substrate material and form an initial core hole. For this purpose, the portion of the liquid-jet laser extending beyond the tool tip is applied. In the finishing step, the laser beam is shut off, and the machine tool can begin to rotate at the desired speed to remove remaining material from the core hole. The liquid jet can be kept flowing through the machine tool toward the workpiece as a coolant for both the machine tool and the workpiece substrate.

[0204] Figures 28A to 28D illustrate configurations for cooling a rotary tool according to some embodiments. Figure 28A shows a water injection nozzle 2871 that pours a cooling liquid (e.g., water, coolant, or lubricating fluid) into the workpiece (e.g., substrate 2800). The cooling water flow 2871 can remove heat generated by friction between the rotary tool and the substrate. During a machining process using the rotary tool 2820, the tool 2820 and the substrate 2800 can be cooled by a liquid cooling flow (e.g., water injection nozzle 2871). The water can have an ambient temperature or a lower temperature, for example, less than 20, 15, or 10 degrees Celsius.

[0205] Figure 28B shows a configuration in which a gas cooling process (e.g., an air nozzle 2872 pointing to a rotary tool or a substrate area being machined) can be used.

[0206] Figure 28C illustrates a configuration in which a liquid or gas cooling process can be used in a channel rotary tool. Liquid 2871A can be supplied to a conduit inside the rotary tool, and then it can flow outward to the sidewall surface of the substrate or hole.

[0207] Figure 28D illustrates a configuration using a liquid jet from a liquid jet-guided laser head to cool a rotating tool with a hollow tool head. A liquid jet 2871* from the liquid jet-guided laser head (e.g., a liquid flow from a laser beam without internal reflection) can be used to travel inside the hollow rotating tool for cooling the rotating tool during a smoothing process.

[0208] Figures 29A to 29C illustrate flowcharts for cooling a mechanical rotary tool according to some embodiments. In Figure 29A, operation 2900 smooths holes in a substrate by rotating the mechanical rotary tool. The mechanical rotary tool is subjected to a liquid or gas flow for cooling. Alternatively, a liquid flow is provided for cooling via a conduit in the mechanical rotary tool. Alternatively, the substrate is immersed in a liquid bath for cooling the mechanical rotary tool.

[0209] In Figure 29B, operation 2920 allows a liquid or gas flow to flow to the outer surface or inner conduit of the mechanical rotating tool for cooling the mechanical rotating tool during the smoothing of holes in the substrate.

[0210] In Figure 29C, operation 2940 positions a mechanical rotary tool below a liquid jet-guided laser head, wherein a liquid column from the liquid jet-guided laser head is configured to pass through an inner conduit in the mechanical rotary tool during a process that smooths holes in a substrate.

[0211] In some embodiments, an alignment module (e.g., a camera) can be used to align the mechanical rotating tool with the initial hole formed by the liquid jet. After flipping the substrate, the alignment module can be used to align the mechanical rotating tool to ensure that the top surface process is aligned with the bottom process.

[0212] To precisely finish the mandrel to the final hole diameter, the center axis of the machine tool and the center axis of the mandrel must be perfectly aligned. A alignment camera can be used to locate the center axis of the mandrel. The alignment camera can be mounted on a mounting plate, and the tool spindle is also mounted to the mounting plate. The alignment camera and the tool spindle can have a known offset distance between their respective center axes. The alignment camera can have at least one optical element (e.g., a lens) and at least one spatial detector (e.g., a camera).

[0213] To finish the initial hole formed by the previous liquid jet process, in the first step, a alignment camera measures the position of the central axis of the core hole. In the second step, the alignment camera and the mounting plate on which the tool spindle is mounted can be moved up to a distance equal to the offset distance between the alignment camera and the central axis of the tool spindle and the machine tool. Once the machine tool axis is precisely positioned above the central axis of the core hole, the tool spindle can be lowered to begin finishing the core hole to the final hole diameter. The machine tool can be moved up and down. Alternatively, the machine tool moves along the core hole from the first surface of the substrate in only one direction and through the second opposite surface of the substrate.

[0214] For example, after flipping the substrate, an alignment module can be used to align the rotary tool with the opposite opening of the initial hole. For example, after smoothing the first portion of the initial hole from the first opening side, the substrate can be flipped to expose the bottom surface of the substrate to the rotary tool. The alignment camera can determine the position of the central axis of the second opening of the core hole. The mounting plate on which the alignment camera and tool spindle are mounted can be moved by a distance equal to the offset distance between the alignment camera and the central axis of the tool spindle and the machine tool. Once the machine tool axis is precisely positioned above the central axis of the core hole, the tool spindle can be lowered to begin finishing the core hole to the final hole diameter.

[0215] Figures 30A and 30B illustrate the configuration of an alignment module according to some embodiments. In Figure 30A, a rotating tool 3020 and an alignment module 3074 can be mounted on a mounting plate 3077. The distance 3078 between the alignment module and the rotating tool can be determined and then used to align the rotating tool.

[0216] Figures 30B(a) to 30B(b) illustrate the process for aligning a rotating tool with an initial hole 3001 in a substrate 3000. An alignment module can be used to locate the centerline of the initial hole. Then, a mounting plate containing the alignment module and the rotating tool can be moved a distance equal to the separation distance 3078 between the alignment module and the rotating tool. The rotating tool is then aligned with the initial hole and can be lowered to smooth the initial hole.

[0217] Figures 31A and 31B illustrate another configuration of the alignment module according to some embodiments. In Figure 31A, the rotating tool 3120 and the alignment module 3174* can be mounted on the mounting plate 3177*, wherein the alignment module is mounted in the opposite direction to the rotating tool, for example, the substrate is configured to be positioned between the alignment module and the rotating tool. The alignment module can be aligned with the rotating tool, for example, the alignment module can be aligned with the centerline of the rotating tool.

[0218] Figure 31B illustrates the process for aligning a rotating tool with an initial hole 3101 in the substrate 3100. An alignment module can be used to find the centerline of the initial hole. The rotating tool can then be lowered to smooth the initial hole, as it has been aligned with the centerline of the initial hole.

[0219] Figures 32A and 32B illustrate flowcharts for aligning a mechanical rotary tool according to some embodiments. In Figure 32A, operation 3200 couples an alignment module to the mechanical rotary tool, wherein the alignment module is configured to position a hole in a substrate from either the top or bottom surface. The distance between the alignment module and the mechanical rotary tool is used to align the mechanical rotary tool with the hole. If the alignment module is positioned in the opposite direction to the rotary tool, the distance can be zero.

[0220] In Figure 32B, operation 3220 uses an alignment module coupled to a mechanical rotating tool to determine the position of a hole in the substrate. Operation 3230 optionally moves the mechanical rotating tool by a predetermined distance between the alignment module and the mechanical rotating tool to align it with the position of the hole. This operation is optional if the alignment module is coupled to the rotating tool in the opposite direction, for example, if the alignment module is configured to position the hole from the bottom surface of the substrate. Operation 3240 uses the mechanical rotating tool to smooth the hole. Operation 3250 repeats the above steps to align and smooth other holes in the substrate.

[0221] In some embodiments, an inspection module (e.g., a camera) can be used to inspect the quality of holes finished by a mechanical rotary tool. The inspection module can be used to continue or terminate the smoothing process for subsequent initial holes. For example, if the inspected hole passes a quality test, such as sufficient sidewall surface roughness and no deterioration at the hole inlet and outlet edges, the rotary tool can move to a subsequent initial hole to continue processing. Alternatively, if the inspected hole fails a quality test, such as insufficient sidewall surface roughness or indication of deterioration at the hole inlet or outlet edges, the process can be terminated.

[0222] In some embodiments, the size and quality of precision-machined holes in a substrate can be measured. For example, precision components of gas distribution and homogenization plates for semiconductor processing equipment typically require machining hundreds or even thousands of precision holes in a thick ceramic substrate. To ensure stable and repeatable gas distribution, the inlet and outlet of each hole must have sharp edges without any circumferential damage. The machine used to create such holes may have a core-hole drilling step using a liquid jet-guided laser or an electrical discharge machining process. The core holes can be finished with mechanical tools to the desired final hole diameter and quality. Sometimes, during the core-hole drilling or hole finishing process, the holes may be damaged; for example, the inlet or outlet may have broken sections. This may be caused by impurities in the substrate material or by wear, for example, on the mechanical tools used to finish the core holes to the desired hole diameter. To avoid further processing of substrates with one or more defective holes, each hole can be inspected with mechanical tools after the processing steps.

[0223] In some embodiments, a hole inspection process can also be applied after the core hole is produced by a liquid jet-guided laser or electrical discharge machining process. A tool spindle with mechanical tools can be mounted on a mounting plate inside the machine for processing the substrate. An inspection camera can be mounted to the same mounting plate. The inspection camera can include an illumination module for illuminating the substrate surface. The inspection camera can contain at least one optical element adapted to image an area equal to or larger than the hole diameter onto a sensing device (e.g., a CCD camera). The illumination module can illuminate an area equal to or larger than the hole diameter. Defects around the hole circumference can be detected by variations in shape and brightness compared to the desired hole profile.

[0224] In some embodiments, the top inspection module and the bottom inspection module can be configured to simultaneously measure the size and quality of the finished holes in the substrate on both sides of the substrate. The optical axes of the top and bottom inspection modules can be the same; for example, the top and bottom inspection modules have the same optical axis. The top inspection camera may include a top illumination module for illuminating the upper surface of the substrate and for illuminating through the holes toward the bottom inspection camera. The bottom inspection camera may include a bottom illumination module for illuminating the lower, opposite surface of the substrate and for illuminating through the holes toward the top inspection camera.

[0225] In some embodiments, the top illumination module can illuminate the hole entrance. The top inspection camera can detect defects around the hole circumference by analyzing changes in shape and brightness compared to the desired hole profile. Such analysis can be performed by connecting the top inspection camera to, for example, a computing device. In addition to activating the top illumination module, the bottom illumination module can be further activated, allowing the top inspection camera to detect defects inside the hole itself, such as out-of-roundness, high roughness, or particles on the hole sidewalls. The top and bottom illumination modules can be activated simultaneously or sequentially.

[0226] In some embodiments, the bottom illumination module can illuminate the hole outlet. The bottom inspection camera can detect defects around the hole circumference by analyzing changes in shape and brightness compared to the desired hole profile. Such analysis can be performed by connecting the top inspection camera to, for example, a computing device. In addition to activating the bottom illumination module, the top illumination module can be further activated, allowing the bottom inspection camera to detect defects on the inner side of the hole itself, such as out-of-roundness, high roughness, or particles on the hole sidewalls.

[0227] Figures 33A and 33B illustrate the configuration of an inspection module according to some embodiments. In Figure 33A, a rotating tool 3320 and an inspection module 3375 can be mounted on a mounting plate. The distance between the inspection module and the rotating tool can be determined and then used to align the inspection module after the rotating tool has completed its processing. The inspection module may include a light source 3375A, such as an LED light. The inspection module may include an inspection camera 3375B for capturing images of the processed holes. The inspection module may include a processing module 3375C for analyzing the images captured by the camera 3375B.

[0228] During operation, the rotary tool 3320 can finish the initial hole, for example, by smoothing the sidewalls and giving the initial hole the final desired diameter. The inspection module and the mounting module on which the rotary tool is mounted can be moved equal to the separation distance between the inspection module and the rotary tool. The inspection module can then inspect the quality of the hole just processed by the rotary tool.

[0229] In Figure 33B, the top inspection module 3375 and the bottom inspection module 3375* can be coupled to the rotary tool 3320. The top and bottom inspection modules can be aligned, for example, so that they have the same optical axis for inspecting the top and bottom portions of the hole.

[0230] Figures 34A and 34B illustrate flowcharts for inspecting final holes in a substrate according to some embodiments. In Figure 34A, operation 3400 couples an inspection module to a mechanical rotary tool, wherein the inspection module is configured to inspect the characteristics of holes in the substrate from either the top or bottom surface. The distance between the inspection module and the mechanical rotary tool is used to align the inspection module with the holes after smoothing by the rotary tool.

[0231] In Figure 34B, operation 3420 uses a mechanical rotating tool to smooth the holes in the substrate, wherein the rotating tool is coupled to an inspection module. Operation 3430 moves the mechanical rotating tool by a predetermined distance between the inspection module and the mechanical rotating tool to align the inspection module with the holes. Operation 3440 uses the inspection module to inspect the holes. Operation 3450 repeats the previous steps to smooth and inspect other holes in the substrate.

[0232] In some embodiments, the present invention discloses a method and system for forming holes in a substrate that can be used in gas distribution plates and homogenization plates. The method may include forming an initial hole in the substrate using a liquid jet-guided laser system, an electrical discharge machining (EDM) system, or a combination of a liquid jet-guided laser system and an EDM system. The method may further include finishing the formed initial hole, for example, enlarging the initial hole to a desired final diameter while ensuring that the sidewalls of the final hole are smooth and that the inlet and outlet edges are not damaged. The finishing process can be performed by a mechanical rotary tool (e.g., a drill bit, reamer, milling drill bit, boring bar, or honing drill bit).

[0233] In some embodiments, the hole forming process and the hole finishing process can be performed in different devices (e.g., a first device of a liquid jet-guided laser system for forming an initial hole and a second device of a mechanical rotary tool for finishing the initial hole).

[0234] Figure 35 shows a flowchart of a process for fully forming a hole in a substrate according to some embodiments. Full hole formation may include forming an initial hole in the substrate and finishing the initial hole with a mechanical tool to a desired hole diameter with desired characteristics.

[0235] Operation 3500: Machining at least one hole in a substrate, wherein the substrate is a ceramic substrate, and the ceramic material is one of silicon, silicon carbide, aluminum nitride, silicon nitride, ceramic matrix composite (CMC), metal matrix composite (MMC), boron carbide, or titanium nitride. Operation 3510: Determining the desired hole diameter, wherein the desired hole diameter is less than 2 mm. Operation 3520: Drilling a core hole, wherein a liquid jet-guided laser or electrical discharge machining process is applied to create a core hole diameter equal to or smaller than the desired final hole diameter. Operation 3530: Determining the precise position of the core hole, wherein a camera is used to measure the position of the hole as the offset distance to the spindle. Operation 3540: Providing a machine tool to the spindle, wherein the machine tool is one of a drill bit, a reamer, or a milling tool, and wherein at least the end portion of the tool's cutting surface is made of one of a carbide or synthetic diamond material. Operation 3550 finishes the core hole to the desired hole diameter, wherein mechanical tools are used to remove any remaining material between the core hole diameter and the desired hole diameter. The substrate may also include a metal substrate and other workpieces with holes.

[0236] In some embodiments, the present invention discloses the integration of a liquid jet for forming holes in a substrate with a mechanical rotary cutting tool. The integrated system may include a liquid jet-guided laser head having a liquid source configured to generate a liquid jet and a laser power source configured to form an internally reflected laser beam in the liquid jet generated by the liquid source. The liquid jet-guided laser head may include a coaxial gas flow surrounding the liquid jet to minimize interference with the liquid jet. The integrated system may include a mechanical rotary tool configured to enlarge the initial hole and smooth the surface of the enlarged hole without damaging the inlet and outlet edges of the hole.

[0237] The machine tool has a coaxial central bore that fluidly connects the upper part of the tool to the tip of the tool. Due to the long working length, a liquid jet-guided laser can be guided through the central bore in the machine tool.

[0238] Figure 36 illustrates a configuration of an integrated system of liquid jet and mechanical rotary tool according to some embodiments. The integrated system 3626, such as a combination of a liquid jet-guided laser head 3610 and a mechanically hollow rotary tool head 3620, can be configured to form an initial hole, along with finishing the initial hole. The liquid jet-guided laser head 3610 may include a housing holding a viewing window 3612. Below the window 3612, a liquid jet nozzle 3615 is present. A liquid source (e.g., a water source 3614) can be forced into the space between the viewing window 3612 and the nozzle 3615 to form a layered liquid jet 3616A. To process material, a laser beam from a laser source 3611 is focused and guided through the window 3612 and through the orifice of the liquid jet nozzle 3615 into the layered liquid jet 3616A. The focused laser beam 3613 can be confined within the liquid jet 3616A, and the energy of the laser beam 3616B can be guided toward the workpiece substrate 3600 by total internal reflection from the inside of the liquid jet.

[0239] The liquid-jet guided laser head 3610 may include an air-jet module to provide a coaxial gas flow around the liquid jet. Below the liquid-jet nozzle 3615, the liquid-jet guided laser passes through a conduit within the air-jet module 3627. A high-capacity stream of compressed gas 3617 is provided through the external and mechanically spaced conduits of the air-jet module 3627, this high-capacity stream traveling parallel to the liquid-jet guided laser 3616 and toward the surface of the substrate 3600. The compressed gas stream 3618 acts as a coaxially spaced shield that prevents backflow-induced interference from the liquid-jet guided laser 3616.

[0240] The hollow mechanical rotating tool head 3620 may include a hollow mechanical rotating tool, which may have a conduit through which the rotating tool passes. The hollow mechanical rotating tool head 3620 may be positioned such that a liquid jet from a liquid jet-guided laser head may enter the conduit, for example, to cool the hollow mechanical rotating tool.

[0241] The motion mechanism can be coupled to the integrated system to move, for example, a liquid jet-guided laser head and a mechanical rotating tool in a plane normal to the liquid jet or in three-dimensional movement parallel to and normal to the liquid jet.

[0242] The liquid jet-guided laser beam 3616 can be configured to, for example, remove cylindrical material by a straight cutting process by traveling multiple times along a circular profile, or to create a hole with an initial diameter of 3606 in a substrate by performing multi-pass rasterization inside a closed-loop profile to form a hole inside the closed-loop profile.

[0243] Mechanical rotary tools can be configured to finish initial holes, for example, enlarge the initial hole to a final diameter of 3602 and smooth the sidewalls of the final hole. 100:Substrate 101: Precision Hole / Bore Hole 102: Diameter 103: Depth 104: Sharp edges 105: Surface finishing 200:Substrate 201*: Through hole 202: Final diameter 206: Initial diameter 210: Liquid Jet Guided Laser Head 211: Laser source 212: Window 213: Focused Laser Beam 214: Liquid Source 215: Nozzle 216: Liquid Jet Guided Laser Beam 216A: Liquid Jet 216B: Laser Beam 220: Mechanical Rotary Tool Head 220*: Hollow Rotary Tool Head 221: Mechanical Rotary Tools 221*: Hollow Rotary Tool 222: Tool diameter 223: Round or oval tip 224: Move down 224*: Move down 226: Combined System 277: Catheter 300: Operation 310: Operation 330: Operation 340: Operation 360: Operation 370: Operation 400: Workpiece substrate 401: Micro-hole / Bore Hole 401*: Hole / Bore Hole 410: Liquid Jet Guided Laser Head 412: Window 413: Laser Beam 414: Water Source 415: Liquid jet nozzle 416: Liquid Jet Guided Laser 416A: Laminar liquid jet 416B: Laser Beam 417: Compressed gas source 418: Compression of gas flow 427: Air Jet Module 500:Substrate 501: Hole or bored hole / through hole 516: Laser / Liquid Jet Guiding 530: Circular Machining Motion 531: Incision 532: Cylindrical pin 533: Spiral Motion 534: Blind Hole / Drilling 600:Substrate 602: Final hole diameter 605: Final sidewall roughness 605*: Initial sidewall surface 606: Initial hole diameter 616: Liquid Jet 700: Operation 710: Operation 720: Operation 730: Operation 740: Operation 750: Operation 800: Operation 820: Operation 840: Operation 860: Operation 900:Substrate 901: Initial Hole / Through Hole / Core Hole 906: Diameter 916: Liquid Jet Guided Laser 934: Blind Hole 1000: Operation 1020: Operation 1040: Operation 1050: Operation 1100:Substrate 1101: Kong 1112: Liquid Jet Guided Laser 1116: Liquid Jet Guided Laser 1141: Water Injection Nozzle / Hot Water Flow 1142: Infrared and / or inductive devices 1143: Completely submerged 1144: Partially submerged 1145: Air conditioning unit 1200: Operation 1220: Operation 1240: Operation 1260: Operation 1270: Operation 1280: Operation 1300:Substrate 1301: Kong 1311*: Laser on / off mode 1316: Liquid Jet Guided Laser 1351: Cut through the acoustic detector 1351*: Sound intensity emitted 1352: Cut through the optical detector 1352*: Laser intensity emitted 1353: Instant 1354: Laser Cutting Moment 1354*: Laser shut-off moment 1355: Sound intensity 1356: Laser intensity at launch 1357: Sound intensity emitted 1400: Operation 1410: Operation 1420: Operation 1440: Operation 1450: Operation 1460: Operation 1500:Substrate 1501: Initial hole / core hole diameter 1502: Final diameter 1507: Conductor 1507*: EDM electrode 1508: EDM electrode diameter 1516: Liquid Jet 1535: EDM Power Supply 1600:Substrate 1602: Final diameter 1607: Electrode 1608: Diameter 1635: EDM Power Supply 1700: Operation 1710: Operation 1720: Operation 1740: Operation 1750: Operation 1770: Operation 1780: Operation 1800:Substrate 1801: Through hole 1816: Liquid Jet 1834: Blind Hole 1900: Operation 1910: Operation 1920: Operation 1930: Operation 1940: Operation 1950: Operation 1960: Operation 2000: Ceramic substrate 2001: Precision Hole 2020: Mechanical Rotary Tools 2020*: Mechanical Rotary Tools 2023: Tool Tips 2061: Material Fragmentation 2061*: Damaged 2062: Material Fragmentation 2062*: No broken edges or damage 2066: Flip substrate 2120: Machine Tools 2163: Tool tip 2163*: Tool tip 2164: Main cutting surface 2164*: Secondary cut (or non-cut) surface 2165: concave diameter 2200: Operation 2220: Operation 2240: Operation 2300:Substrate 2301: Through hole 2320: Rotate Tool 2366: Flip board 2400:Substrate 2420: Rotate Tool 2434: Blind Hole 2466: Flip substrate 2500:Substrate 2520: Rotate Tool 2534: Blind Hole 2566: Flip substrate 2600:Substrate 2601: Through hole 2620: Rotate Tool 2620*: Rotate Tool 2634: Blind Hole 2700: Operation 2720: Operation 2740: Operation 2800:Substrate 2820: Rotate Tool 2871: Water Injection Nozzle / Cooling Water Flow 2871A: Liquid 2871*: Liquid Jet 2872: Air Nozzle 2900: Operation 2920: Operation 2940: Operation 3000:Substrate 3001: Initial Hole 3020: Rotate Tool 3074: Alignment Module 3077: Mounting plate 3078: Separation distance 3100:Substrate 3120: Rotate Tool 3174*: Alignment Module 3177*: Mounting plate 3200: Operation 3220: Operation 3230: Operation 3240: Operation 3250: Operation 3300:Substrate 3320: Rotate Tool 3375: Check Module 3375A: Light Source 3375B: Check the camera 3375C: Processing Module 3375*: Bottom Inspection Module 3400: Operation 3420: Operation 3430: Operation 3440: Operation 3450: Operation 3500: Operation 3510: Operation 3520: Operation 3530: Operation 3540: Operation 3550: Operation 3600: Workpiece substrate 3602: Final diameter 3606: Initial diameter 3610: Liquid Jet Guided Laser Head 3611: Laser source 3612: Window 3613: Focused Laser Beam 3614: Water Source 3615: Liquid Jet Nozzle 3616: Liquid Jet Guided Laser 3617: Compressed gas source 3618: Gas Flow 3620: Hollow Rotary Tool Head 3626: Integrated System 3627: Air Jet Module

Claims

1. A method for forming a hole through a substrate using a liquid jet-guided laser beam, the method comprising: guiding a liquid jet toward the substrate; guiding a laser beam into the liquid jet and toward the substrate; and moving the liquid jet and the laser beam on the substrate along the closed shape of the hole.

2. The method of forming a hole through a substrate using a liquid jet-guided laser beam as described in claim 1, further comprising moving the liquid jet and the laser beam multiple times along the closed shape on the substrate.

3. The method of forming a hole through a substrate using a liquid jet-guided laser beam as described in claim 1, further comprising smoothing the hole after forming the hole using the liquid jet and the laser beam.

4. The method of forming a hole through a substrate using a liquid jet-guided laser beam, as described in claim 1, wherein the hole extends completely through the substrate.

5. The method of forming a hole through a substrate using a liquid jet-guided laser beam as described in claim 1, further comprising causing gas to flow coaxially around the liquid column and the laser beam.

6. The method of forming a hole through a substrate using a liquid jet-guided laser beam, as described in claim 1, wherein the hole is an elongated groove.

7. The method of forming a hole through a substrate using a liquid jet-guided laser beam, as described in claim 1, wherein: The method of guiding the liquid column includes guiding the liquid column toward a first side of the substrate; the method of guiding the laser beam includes guiding the laser beam into the liquid column and toward the first side of the substrate; the method of moving includes moving the liquid column and the laser beam along the closed shape of the aperture on the first side of the substrate; and the method of further includes: guiding a second liquid column toward a second side of the substrate, the second side being opposite to the first side; guiding a second laser beam into the second liquid column and toward the second side of the substrate; and moving the second liquid column and the second laser beam along the closed shape of the aperture on the second side of the substrate.

8. The method of forming a hole through a substrate using a liquid jet-guided laser beam, as claimed in claim 1, wherein the hole is between 75% and 99% of the final size of the hole.

9. The method of forming a hole through a substrate using a liquid jet-guided laser beam as claimed in claim 1, wherein the substrate comprises at least one of silicon, silicon carbide, aluminum nitride, silicon nitride, titanium nitride, boron carbide, ceramic matrix composite (CMC), or metal matrix composite (MMC).

10. The method of forming a hole through a substrate using a liquid jet-guided laser beam as described in claim 1, further comprising heating the substrate during the movement of the liquid jet and the laser beam on the substrate.

11. The method of forming a hole through a substrate using a liquid jet-guided laser beam as described in claim 10, wherein heating the substrate comprises heating the substrate by using a nozzle to allow liquid to flow over the substrate.

12. The method of forming a hole through a substrate using a liquid jet-guided laser beam, as claimed in claim 10, wherein heating the substrate comprises heating the substrate using an infrared light source.

13. The method of forming a hole through a substrate using a liquid jet-guided laser beam, as described in claim 10, wherein heating the substrate comprises heating the substrate using an inductive heat source.

14. The method of forming a hole through a substrate using a liquid jet-guided laser beam, as claimed in claim 10, wherein heating the substrate comprises heating the substrate by immersing the substrate in a fluid.

15. The method of forming a hole through a substrate using a liquid jet-guided laser beam, as claimed in claim 14, wherein the immersion comprises completely immersing the substrate in the fluid.

16. The method of forming a hole through a substrate using a liquid jet-guided laser beam, as claimed in claim 10, wherein heating the substrate comprises heating the substrate using a heating gas.

17. The method of forming a hole through a substrate using a liquid jet-guided laser beam as described in claim 1, further comprising heating the substrate before moving the liquid jet and the laser beam on the substrate.

18. The method of forming a hole through a substrate using a liquid jet-guided laser beam as claimed in claim 1, further comprising: detecting a cut through the hole through the substrate; and, based on the detection of the cut through the hole, selectively stopping: guiding the liquid jet toward the substrate; and guiding the laser beam into the liquid jet.

19. The method of forming a hole through a substrate using a liquid jet-guided laser beam as described in claim 18, wherein detecting the perforation includes detecting the perforation using at least one of an optical sensor and an acoustic sensor.

20. The method of forming a hole through a substrate using a liquid jet-guided laser beam as claimed in claim 19, wherein detecting the penetration includes detecting the penetration when at least one of the optical sensor and the acoustic sensor measures an increase in at least one of light and sound.

21. The method of forming a hole through a substrate using a liquid jet-guided laser beam as described in claim 18, further comprising: outputting light onto the substrate using a light source having a first wavelength different from a second wavelength of the laser beam, wherein detecting the cut includes detecting the cut based on the detection of light of the first wavelength by an optical sensor.

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