Method and system for machining precise micro-holes in a thick ceramic substrate

Abstract

This technology provides a method for machining precise micro-holes in thick substrates using a combination of a liquid jet and a mechanical rotary tool. [Solution] A liquid jet guided laser can be used to quickly drill core holes in a ceramic substrate. By applying a sensor to detect the cutting point in the liquid jet guided laser drilling step, a rapid and closed-loop controlled machining process is possible. Heating the substrate can speed up the liquid jet guided laser drilling process. Mechanical tools such as drills, reamers, and mills can be applied to finish the core holes to the desired bore diameter. The cutting surface of the mechanical tool may preferably be made of diamond material. An inspection camera and lighting system can be applied to inspect each machine-finished bore as part of the drilling process.

Description

[Background technology]

[0001] Precision components such as gas distribution plates and homogenization plates for semiconductor processing equipment typically require machining hundreds or thousands of tiny precision holes into a thick ceramic substrate. To avoid contamination of silicon or silicon carbide product wafers, these gas distribution plates and homogenization plates are typically made from silicon or silicon carbide of equivalent or higher purity. In addition to the increased number of holes, these holes require a high level of surface finish. The inner wall of each hole must be mirror-smooth to prevent the adhesion of unwanted particles that could contaminate the actual product wafer. To ensure stable and reproducible gas distribution, both the inlet and outlet of each hole must have sharp, undamaged edges around the circumference.

[0002] Today, holes in gas distribution plates and homogenized plates are created in various ways. Holes can be drilled sequentially using a drill bit. Alternatively, holes can be drilled sequentially using an electrical discharge machining process, which erodes the material inside the hole with a wire. Another method involves using an ultrasonic plate, which applies ultrasonic vibrations to the pin pattern of the hole being machined and a pin pattern in the opposite direction, removing the material inside the hole. In addition, all holes or groups of holes can be machined simultaneously using an electrical discharge machining process with an electrode plate having the pin pattern of the hole being eroded and a pin pattern in the opposite direction.

[0003] While ultrasonic treatment or electrical discharge machining are relatively quick methods for simultaneously creating holes, typically, post-processing such as reaming is required for each hole to achieve the desired mirror finish. Sequential drilling with a milling tool typically achieves the desired mirror finish without post-processing. However, drilling with mechanical drilling tools carries a higher risk of material chipping at the hole entrance and especially at the exit. Furthermore, when processing ceramic materials such as silicon and silicon carbide (but not limited to these), drilling tool wear is severe, limiting tool life.

[0004] A typical gas distribution and / or homogenization plate is 10–15 mm thick and may have 1000–2000 holes with a diameter of 0.2–0.8 mm. Drilling each hole can take 3–4 minutes. For example, if the drill bit breaks at 1480 of 1500 holes, the entire substrate may have to be discarded, resulting in hours of wasted machining work. Therefore, there is a substantial need for improved and more efficient methods for machining a large number of small holes in thick ceramic substrates. Those skilled in the art will appreciate and understand that the present invention is not limited to holes in gas distribution and homogenization plates, but recognizes its applicability to a wider range of technical ceramic materials and applications requiring precision holes. [Overview of the project]

[0005] In some embodiments, the present invention discloses a method and system for machining precision micro-holes in a thick substrate. The substrate may be a ceramic material with hundreds or thousands of holes machined into it. The holes can be formed by applying a hybrid process to which a core-hole drilling process and a hole-finishing process are applied. A liquid jet guided laser can be used to rapidly drill core holes in the ceramic substrate. Sensors can be applied to detect the cutting point of the liquid jet guided laser drilling step, enabling a rapid and closed-loop controlled machining process. Heating the substrate can speed up the liquid jet guided laser drilling process. Mechanical tools such as drills, reamers, or mills can be applied to finish the core holes to the desired diameter. The cutting surface of the mechanical tool can preferably be made of diamond material. An inspection camera and illumination system can be applied to inspect each machine-finished hole as part of the drilling process. [Brief explanation of the drawing]

[0006] [Figure 1A] Figure 1A shows a substrate having continuous holes or bores according to several embodiments. [Figure 1B] Figure 1B shows a substrate having continuous holes or bores according to several embodiments.

[0007] [Figure 2A] Figure 2A shows configurations for hybrid processing of holes in a substrate according to several embodiments. [Figure 2B] Figure 2B shows configurations for hybrid processing of holes in a substrate according to several embodiments.

[0008] [Figure 3A] Figure 3A shows flowcharts for forming holes in a substrate according to several embodiments. [Figure 3B] Figure 3B shows flowcharts for forming holes in a substrate according to several embodiments. [Figure 3C]Figure 3C shows a flowchart for forming holes in a substrate according to some embodiments.

[0009] [Figure 4] Figure 4 shows the configuration of a liquid jet guided laser head according to some embodiments.

[0010] [Figure 5A] Figure 5A shows a method for drilling holes in a substrate with a liquid jet guided laser beam according to some embodiments. [Figure 5B] Figure 5B shows a method for drilling holes in a substrate with a liquid jet guided laser beam according to some embodiments.

[0011] [Figure 6A] Figure 6A shows the sidewall roughness of a hole according to some embodiments. <000H100> [Figure 6B] Figure 6B shows the sidewall roughness of a hole according to some embodiments.

[0012] [Figure 7] Figure 7 shows a flowchart for forming an initial hole in a substrate according to some embodiments.

[0013] [Figure 8A] Figure 8A shows a flowchart for forming an initial hole in a substrate according to some embodiments. [Figure 8B] Figure 8B shows a flowchart for forming an initial hole in a substrate according to some embodiments. [Figure 8C] Figure 8C shows a flowchart for forming an initial hole in a substrate according to some embodiments. [Figure 8D] Figure 8D shows a flowchart for forming an initial hole in a substrate according to some embodiments.

[0014] [Figure 9A]Figure 9A shows the configuration of holes formed by a liquid jet according to several embodiments. [Figure 9B] Figure 9B shows the configuration of holes formed by a liquid jet according to several embodiments.

[0015] [Figure 10A] Figure 10A shows flowcharts for forming initial holes in a substrate according to several embodiments. [Figure 10B] Figure 10B shows flowcharts for forming initial holes in a substrate according to several embodiments. [Figure 10C] Figure 10C shows flowcharts for forming initial holes in a substrate according to several embodiments.

[0016] [Figure 11A] Figure 11A shows configurations for heating a substrate to accelerate a liquid jet-guided laser hole formation process, according to several embodiments. [Figure 11B] Figure 11B shows configurations for heating a substrate to accelerate a liquid jet-guided laser hole formation process, according to several embodiments. [Figure 11C] Figure 11C shows configurations for heating a substrate to accelerate a liquid jet-guided laser hole formation process, according to several embodiments. [Figure 11D] Figure 11D shows configurations for heating a substrate to accelerate a liquid jet-guided laser hole formation process, according to several embodiments.

[0017] [Figure 12A] Figure 12A shows flowcharts for adjusting the substrate temperature during a liquid jet process according to several embodiments. [Figure 12B] Figure 12B shows flowcharts for adjusting the substrate temperature during a liquid jet process according to several embodiments. [Figure 12C]Figure 12C shows flowcharts for adjusting the substrate temperature during a liquid jet process according to several embodiments. [Figure 12D] Figure 12D shows flowcharts for adjusting the substrate temperature during a liquid jet process according to several embodiments.

[0018] [Figure 13A] Figure 13A shows sensor configurations for a liquid jet guide laser process to detect the termination point of a liquid jet process, according to several embodiments. [Figure 13B] Figure 13B shows sensor configurations for a liquid jet guide laser process for detecting the termination point of a liquid jet process, according to several embodiments. [Figure 13C] Figure 13C shows sensor configurations for a liquid jet guide laser process for detecting the termination point of a liquid jet process, according to several embodiments.

[0019] [Figure 14A] Figure 14A shows flowcharts for detecting the termination point of a liquid jet process according to several embodiments. [Figure 14B] Figure 14B shows flowcharts for detecting the termination point of a liquid jet process according to several embodiments.

[0020] [Figure 15A] Figure 15A shows a process for forming an initial hole using liquid jet and electrical discharge machining according to several embodiments. [Figure 15B] Figure 15B shows a process for forming an initial hole using liquid jet and electrical discharge machining according to several embodiments. [Figure 15C] Figure 15C shows a process for forming an initial hole using liquid jet and electrical discharge machining according to several embodiments. [Figure 15D]Figure 15D shows a process for forming an initial hole using liquid jet and electrical discharge machining according to several embodiments.

[0021] [Figure 16A] Figure 16A shows a process for forming an initial hole using electrical discharge machining according to several embodiments. [Figure 16B] Figure 16B shows a process for forming an initial hole using electrical discharge machining according to several embodiments.

[0022] [Figure 17A] Figure 17A shows flowcharts for forming holes in an EDM process according to several embodiments. [Figure 17B] Figure 17B shows flowcharts for forming holes in an EDM process according to several embodiments. [Figure 17C] Figure 17C shows flowcharts for forming holes in an EDM process according to several embodiments.

[0023] [Figure 18A] Figure 18A shows configurations for forming multiple holes in a substrate using a liquid jet, according to several embodiments. [Figure 18B] Figure 18B shows configurations for forming multiple holes in a substrate using a liquid jet, according to several embodiments.

[0024] [Figure 19] Figure 19 shows a closed-loop process for drilling holes with a liquid jet guided laser according to several embodiments.

[0025] [Figure 20A] Figure 20A shows a process for forming holes according to several embodiments. [Figure 20B] Figure 20B shows a process for forming holes according to several embodiments.

[0026] [Figure 21A] Figure 21A shows the configuration of a mechanical rotary tool according to several embodiments. [Figure 21B] Figure 21B shows the configuration of a mechanical rotary tool according to several embodiments. [Figure 21C] Figure 21C shows the configuration of a mechanical rotary tool according to several embodiments.

[0027] [Figure 22A] Figure 22A shows flowcharts for finishing holes in a substrate according to several embodiments. [Figure 22B] Figure 22B shows flowcharts for finishing holes in a substrate according to several embodiments. [Figure 22C] Figure 22C shows flowcharts for finishing holes in a substrate according to several embodiments.

[0028] [Figure 23A] Figure 23A shows a process for finishing an initial through-hole according to several embodiments. [Figure 23B] Figure 23B shows a process for finishing an initial through-hole according to several embodiments.

[0029] [Figure 24A] Figure 24A shows a process for finishing an initial one-sided blind hole according to several embodiments. [Figure 24B] Figure 24B shows a process for finishing an initial one-sided blind hole according to several embodiments. [Figure 24C] Figure 24C shows a process for finishing an initial one-sided blind hole according to several embodiments.

[0030] [Figure 25A] Figure 25A shows a process for finishing an initial one-sided blind hole according to several embodiments. [Figure 25B]Figure 25B shows a process for finishing an initial one-sided blind hole according to several embodiments.

[0031] [Figure 26A] Figure 26A shows a process for finishing a hole using two mechanical rotary tools, according to several embodiments. [Figure 26B] Figure 26B shows a process for finishing a hole using two mechanical rotary tools, according to several embodiments. [Figure 27A] Figure 27A shows flowcharts for preparing initial holes in a substrate according to several embodiments. [Figure 27B] Figure 27B shows flowcharts for preparing initial holes in a substrate according to several embodiments. [Figure 27C] Figure 27C shows flowcharts for preparing initial holes in a substrate according to several embodiments.

[0032] [Figure 28A] Figure 28A shows configurations for cooling a rotary tool according to several embodiments. [Figure 28B] Figure 28B shows configurations for cooling a rotary tool according to several embodiments. [Figure 28C] Figure 28C shows configurations for cooling a rotary tool according to several embodiments. [Figure 28D] Figure 28D shows configurations for cooling a rotary tool according to several embodiments.

[0033] [Figure 29A] Figure 29A shows flowcharts for cooling mechanical rotary tools according to several embodiments. [Figure 29B] Figure 29B shows flowcharts for cooling mechanical rotary tools according to several embodiments. [Figure 29C] Figure 29C shows flowcharts for cooling mechanical rotary tools according to several embodiments.

[0034] [Figure 30A] Figure 30A shows the configuration of the alignment module according to several embodiments. [Figure 30B] Figure 30B shows the configuration of the alignment module according to several embodiments.

[0035] [Figure 31A] 31A shows another configuration of the alignment module according to several embodiments. [Figure 31B] 31B shows another configuration of the alignment module according to several embodiments.

[0036] [Figure 32A] Figure 32A shows flowcharts for aligning mechanical rotary tools according to several embodiments. [Figure 32B] Figure 32B shows flowcharts for aligning mechanical rotary tools according to several embodiments.

[0037] [Figure 33A] Figure 33A shows the configuration of the inspection module according to several embodiments. [Figure 33B] Figure 33B shows the configuration of the inspection module according to several embodiments.

[0038] [Figure 34A] Figure 34A shows flowcharts for inspecting the final holes in a substrate according to several embodiments. [Figure 34B] Figure 34B shows flowcharts for inspecting the final holes in a substrate according to several embodiments.

[0039] [Figure 35] Figure 35 shows flowcharts for completely forming holes in a substrate according to several embodiments.

[0040] [Figure 36] Figure 36 shows the configuration of an integrated system of a liquid jet and a mechanical rotary tool according to several embodiments. [Modes for carrying out the invention]

[0041] In some embodiments, the present invention discloses methods and systems for forming holes, such as through holes or blind holes, in a substrate. The formed holes may have smooth inner surfaces with sharp edges at the entrance and exit of the holes. Perforated substrates that meet the requirements for inner surfaces and edges can be used in gas distribution plates and homogenization plates.

[0042] Figures 1A-1B show substrates having continuous holes or bores according to several embodiments. Gas distribution plates and uniformity plates for semiconductor processing equipment are clear examples of substrates that typically require a number of small precision holes or bores 101 machined within a thick substrate 100. In addition to the number of holes or bores 101, these holes or bores also require a high degree of surface finish 105, along with sharp, undamaged edges 104 at the entrance and exit of the holes or bores. The thickness of the substrate, e.g., the depth 103 of the through holes or bores (e.g., holes or bores that completely penetrate the substrate), can be less than 20 mm (e.g., between 10 mm and 15 mm). The size of the holes or bores, e.g., the diameter 102 of the holes or bores, can be small, e.g., less than 2 mm (e.g., between 0.1 and 1 mm), to ensure uniform gas distribution. Such substrates 100, for example, silicon or silicon carbide product wafers, typically have a circular shape and contain hundreds or thousands of precision holes or bores 101 for use as gas distribution plates and homogenization plates. While circular bores are typical, elongated holes or slots with rounded edges are also applicable depending on the application. The following description describes circular holes, such as holes formed by running a liquid jet along a circular contour. However, the present invention is not limited to circular holes and also includes elongated holes or slots with rounded edges.

[0043] To avoid contamination of silicon or silicon carbide substrates, the substrates are typically made of substrate material of equivalent or higher purity, such as being made of silicon or silicon carbide themselves. Other materials, such as aluminum nitride, silicon nitride, titanium nitride, and boron carbide, as well as ceramic matrix composites (CMCs) and metal matrix composites (MMCs), can also be used. Furthermore, the substrates can be bored or perforated metal substrates or other workpieces.

[0044] 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 being considered ceramic materials. CMCs can improve the crack resistance of ceramic materials by embedding particles or long-lasting fibers, thereby improving the fracture toughness of the composite material system while maintaining the high strength and Young's modulus of the ceramic matrix. Carbon (C), special silicon carbide (SiC), alumina (Al2O3), and mullite (Al2O3-SiO2) fibers are the most commonly used in CMCs. The matrix material of a CMC can be the same, for example, made from C, SiC, alumina, and mullite. For example, common CMCs include C / C, C / SiC, SiC / SiC, and Al2O3 / Al2O3, which can have higher elongation at break, improved fracture toughness, higher thermal shock resistance, and higher dynamic load capacity.

[0045] Metal matrix composites (MMCs) are composite materials that combine at least a metallic component with other materials such as different metals, ceramics, or organic compounds. MMCs can be fabricated by dispersing reinforcing materials in a metal matrix. For example, using carbon fibers in an aluminum matrix results in low density and high strength.

[0046] In some embodiments, the present invention discloses a hybrid process for forming holes in a substrate that can satisfy the requirements of surface smoothness and edge sharpness without damaging the gas distribution plate, for example. The hybrid process may include initial hole formation, for example, by a liquid jet guided laser beam generated in a liquid jet guided laser head of a liquid jet guided laser system, or by an electrical discharge machining process. The hybrid process may include a smoothing or finishing process of the holes, for example, by a mechanical rotary tool such as a drill bit, reamer bit, honing bit, or milling bit. Using a mechanical rotary tool on existing holes can improve throughput, significantly reduce potential damage to the edges of the finished holes, and reduce wear on the mechanical rotary tool.

[0047] Figures 2A to 2B show configurations for hybrid processing of holes in a substrate according to several embodiments. Figures 2A(a) to 2A(b) show configurations in which the initial hole formation and hole finishing processes are performed using different equipment, such as forming the initial holes in a liquid jet guided laser system and finishing the holes in a mechanical rotary system. Figures 2B(a) to 2B(b) show configurations in which the initial hole formation and hole finishing processes are performed using the same equipment, such as a liquid jet guided laser assembly composed of a mechanical rotary assembly.

[0048] In some embodiments, initial hole formation can be performed in a liquid jet guided laser system, which may include a liquid jet guided laser head coupled to an operating mechanism such as two-dimensional xy motion or three-dimensional xyz motion. The liquid jet guided laser head may be configured to generate a liquid jet guided laser beam, which may be a liquid jet (e.g., a column of liquid) having a laser beam that is internally reflected within the liquid jet. The liquid jet can confine the laser beam, for example, by guiding the laser beam so that it remains within the liquid jet. Using the liquid jet guided laser beam, material can be removed from a substrate, for example, by a laser ablation process.

[0049] Figure 2A(a) shows a liquid jet guided laser head 210 configured to generate a liquid jet guided laser beam 216 (for example, a liquid jet 216A having a laser beam 216B that has been internally reflected within the liquid jet 216A). The laser beam 216B is configured for material removal by processes such as laser ablation. The liquid jet 216A is configured to guide the laser beam 216B to prevent the laser beam from deviating.

[0050] A liquid source 214 can be provided in the nozzle 215 of the liquid jet guide laser head 210. The nozzle may include an opening from which the liquid jet 216A can exit. A 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 undergo internal reflection within the liquid jet 216A to form, for example, an internally reflected laser beam 216B.

[0051] 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 the liquid from the liquid source 214 from coming into contact with and contaminating the laser components.

[0052] A liquid jet 216, for example, a liquid jet guided laser beam, is guided onto, for example, a substrate 200, and a through hole 201 having an initial diameter 206. * The liquid jet guide laser head 210 can be moved along a closed-loop contour, such as a circular contour controlled by an xy motion mechanism, or an elongated contour which is an area with an inherently rounded edge. The liquid jet 216 can remove material from the circular contour and cut a cylinder having an initial diameter 206 similar to the diameter of the circular contour. After the liquid jet 216 has penetrated the substrate, the cut cylinder can be removed from the substrate, leaving a hole with an initial diameter 206 similar to the diameter of the circular contour.

[0053] The liquid jet guided laser head 210 can be moved along a helical path or a rastering path such as multiple parallel lines confined within a closed-loop contour. The liquid jet 216 can remove material within the closed-loop contour by the helical or rastering lines to form a hole having an initial diameter 206 similar to the diameter of the closed-loop contour.

[0054] Figure 2A(b) shows the initial hole 201 * The diagram shows a mechanical rotary tool head 220 configured to perform hole finishing, such as enlarging the final hole 201 to have a final diameter of 202, and to smooth the inner surface of the final hole.

[0055] The mechanical rotary tool head 220 may include a mechanical rotary tool 221 having a tool diameter 222 similar to the final diameter 202 of the final hole 201. During operation, the mechanical rotary tool 221 moves through the initial hole 201 * It can rotate while moving downward inward 224. The mechanical rotary tool 221 may have a rounded or elliptical tip 223 which can be configured to minimize damage to the edge of the final hole 201.

[0056] Figures 2B(a) and 2B(b) show the assembly of the liquid jet guided laser head 210 and the mechanical hollow rotary tool head 220. *Figure 226 of the assembly is shown, and this system can be configured to form an initial hole along with its finish. The liquid jet guide laser head 210 can be similar to those described above and can be configured to generate a liquid jet guide laser beam 216, for example, a liquid jet having a laser beam internally reflected within the liquid jet. The liquid jet guide laser beam 216 can be configured to open a hole having an initial diameter 206 in the substrate, for example, by traveling a plurality of paths along a circular contour to cut out a cylindrical material, or by rastering a plurality of paths inside a closed loop contour to form a hole inside the closed loop contour.

[0057] For example, the liquid jet guide laser head 210 can include a liquid source 214 configured to form a liquid jet 216 after passing through a nozzle 215. The laser source 211 can be focused by a lens to form a focused laser beam 213 on the liquid jet 216. The window 212 can be disposed between the focusing lens and the liquid source 214.

[0058] Mechanical hollow rotary tool head 220 * can include a mechanical hollow rotary tool 221 * which may have a conduit 277 passing through the rotary tool 221 * The mechanical hollow rotary tool head 220 * can be arranged, for example, such that a liquid jet from the liquid jet guide laser head enters the conduit 277 to cool the mechanical hollow rotary tool 221 *

[0059] During operation, the substrate 200 is disposed under the combination system 226. The liquid source 214 is turned on to form a liquid jet 216. The laser power supply is turned on to generate a laser beam for internal reflection within the liquid jet 216. The liquid jet 216 is configured to pass through the mechanical rotary tool head 220 * and, for example, the mechanical rotary tool head 220 *The liquid jet 216 passes through the conduit 277 without interfering with it. The liquid jet 216 can form a hole in the substrate having an initial diameter of 206 (Figure 2B(a)).

[0060] After forming the initial hole, the laser source can be turned off, leaving the liquid jet 216 without the internally reflected laser beam. The combination system 226 is used to finish the initial hole, for example, by enlarging the initial hole to the final diameter 202 and to smooth the surface of the final hole, using a mechanical rotary tool 221. * While rotating, move downwards 224 * It is possible (Figure 2B(b)).

[0061] Figures 3A-3C show flowcharts for forming holes in a substrate according to several embodiments. Figure 3A shows holes being formed using different or the same equipment. In operation 300, a liquid jet guided laser beam is used to form holes in the substrate. In operation 310, a mechanical rotary tool is used to smooth the holes.

[0062] Figure 3B shows how multiple holes are formed in a substrate using different equipment. In operation 330, a liquid jet guided laser beam controlled by a first operating mechanism on a first platform is used to form multiple holes in the substrate. In operation 340, a mechanical rotary tool controlled by a second operating mechanism on a second platform is used to smooth the multiple holes.

[0063] In Figure 3C, a single instrument is used to form a hole in the substrate. Operation 360 forms a hole in the substrate, which may include turning on the liquid supply to the liquid jet guided laser head to form a liquid column and turning on the laser source to generate a laser beam configured to reflect internally within the liquid column. Operation 370 smooths the hole, which may include rotating a mechanical rotary tool while turning on the liquid supply to the liquid jet guided laser head to form a liquid column through a conduit passing through the mechanical rotary tool.

[0064] In some embodiments, the present invention discloses the use of a liquid jet guided laser system to form initial holes in a substrate. Liquid jet guided laser technology, such as that disclosed in US Patent Nos. 8,859,988 and US Patent No. 10,022,820, which are incorporated by reference in whole, is known to be able to machine a wide range of materials, including metals as well as ceramic materials such as silicon, silicon carbide, aluminum nitride, silicon nitride, titanium nitride, boron carbide, ceramic matrix composites (CMCs), and metal matrix composites (MMCs).

[0065] Figure 4 shows the configuration of a liquid jet guided laser head according to several embodiments. The liquid jet guided laser head 410 may include a housing that holds a window 412. Below the window 412 is a liquid jet nozzle 415. A liquid source, such as a water source 414, can be pressed into the space between the window 412 and the nozzle 415 to form a laminar flow liquid jet 416A. To process a material, a laser beam 413 from a laser power source is focused and guided through the window 412 to the laminar flow liquid jet 416 through the orifice of the liquid jet nozzle 415. The focused laser beam 413 can be confined within the liquid column 416A, and the energy of the laser beam 416B can be guided toward the workpiece substrate 400 by total internal reflection within the liquid column 416A. The liquid jet guided laser 416 can be applied to precisely machine fine holes or bores 401 in the substrate 400.

[0066] Small, deep hole or bore 401 *To mitigate potential back-jet interference from water during drilling, an air jet module, such as the air jet module disclosed in US Patent No. 10,307,864, can be used. Below the liquid jet nozzle 415, the liquid jet guide laser passes through an internal conduit in the air jet module 427. A high-volume flow from the compressed gas source 417 is provided through an external and mechanically spaced conduit outside the air jet module 427, but the conduit runs parallel to the liquid jet guide laser 416 and toward the surface of the substrate 400. The compressed gas flow 418 acts as a coaxial, spaced shield to avoid interference induced by back-jet from the liquid jet guide laser 416. The liquid jet guide laser process can be carried out using other liquids instead of water.

[0067] The liquid jet guided laser head 410 can be connected to an operating mechanism for moving the liquid jet guided laser head, for example, in a plane perpendicular to the liquid jet 416, or in three-dimensional movement parallel and perpendicular to the liquid jet 416.

[0068] In some embodiments, a liquid jet guided laser head can be used to form initial holes in a substrate. Since a typical liquid jet can have a diameter of 0.02 to 0.08 mm, a hole enlargement process can be used, such as running the liquid jet along a circular contour with a diameter equal to the desired hole dimensions. Alternatively, the liquid jet can run along a rastering pattern to form holes with dimensions equal to the rastering area.

[0069] Figures 5A and 5B illustrate a method for drilling holes in a substrate using a liquid jet guided laser beam according to several embodiments. The diameter of the liquid jet in the liquid jet guided laser head is typically smaller than the typical hole diameter in gas distribution plates and homogenized plates, for example, the diameter of the liquid jet is between 0.02 and 0.08 mm compared to a hole diameter of 0.2 to 2 mm. In operation, the liquid jet 516, which has an internally reflected laser beam inside, typically removes material layer by layer by laser ablation, and thus, to drill holes of depth, the liquid jet can be sprayed continuously in the same location on the substrate or to create multiple passes along the same contour on the substrate.

[0070] To form a larger hole or bore 501 within the substrate 500, the liquid jet guided laser 516 can perform a circular machining operation 530 to form a cut 531 and cut out a cylindrical pin 532, or the liquid jet guided laser 516 can perform a helical operation 533, or a combination of circular and helical machining operations, to remove all the material within the diameter of the blind hole or bore 534. More passes for the helical operation 533 can form a through hole 501 in the substrate 500.

[0071] The liquid jet guided laser 516 can form a hole or bore 501 in the substrate 500 having a clean, sharp-edged entrance and exit. The average sidewall roughness (Ra) of the hole or bore 501 formed by the liquid jet guided laser 516 can be less than 10 micrometers or between 0.25 and 3 micrometers, depending on the substrate material and the energy parameters of the laser beam.

[0072] In some embodiments, the surface roughness of the sidewalls of the holes may depend on the application of a gas distribution plate or a uniform plate. If high roughness is required, holes formed by a liquid jet guided laser head are suitable. If low roughness is required, a finishing or smoothing process performed by a mechanical rotary tool can be used.

[0073] Figures 6A-6B show the roughness of the sidewalls of the holes according to several embodiments. Holes can be formed in the substrate 600 using a liquid jet 616. Typical hole diameters can be between 0.2 and 2 mm, for example, between 0.2 and 1 mm, or between 0.4 and 0.8 mm. Because the diameter of the liquid jet 616 is much smaller, a circular pattern or raster pattern can be used by the liquid jet to enlarge the hole diameter 606. The sidewalls of the holes are roughened 605 after the liquid jet process. * The liquid jet can cut the substrate with a sidewall roughness value depending 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 yield smoother sidewalls, e.g., sidewalls with lower roughness values, but at the cost of lower throughput. In some embodiments, the hole-forming process can achieve high throughput by using a high surface roughness process with a liquid jet and a subsequent smoothing process with a mechanical rotary tool to satisfy the roughness requirements. The mechanical rotary tool enlarges the initial hole diameter 606 to the final hole diameter 602 and the initial sidewall surface 605 * The holes can be smoothed to a final sidewall roughness of 605. For example, a mechanical rotary tool can smooth the sidewalls to an average roughness Ra of less than a few micrometers, such as less than 1 micrometer, less than 0.5 micrometers, or less than 0.1 micrometers.

[0074] In some embodiments, surface roughness can be characterized by a mean roughness Ra, which is the arithmetic mean of filtered roughness profiles determined from the deviation of the centerline within the evaluation length. In practice, Ra can be determined by taking the average of a set of individual measurements of the peaks and valleys of the surface.

[0075] Figure 7 shows flowcharts for forming initial holes in a substrate according to several embodiments. Holes can be formed in the substrate using a liquid jet with an internally reflected laser beam. A liquid jet can be formed using the nozzle of a liquid jet guide laser head. An internally reflected laser beam can also be obtained by aligning the nozzle with the laser beam. In operation 700, the liquid supply to the nozzle of the liquid jet guide laser head is turned on to form a liquid column. In operation 710, the laser power supply focused on the liquid column is turned on to form a laser beam that is internally reflected within the liquid column. In operation 720, the liquid column with the internally reflected laser beam is guided onto the substrate to remove material from the substrate. In operation 730, the liquid column with the internally reflected laser beam is held in place on the substrate to form a hole in the substrate. In operation 740, the liquid column with the internally reflected laser beam is moved along a closed-loop contour on the substrate to cut a column of material within the substrate that has a closed-loop contour shape. In operation 750, a liquid column with an internally reflected laser beam is rasterized along a closed-loop contour on the substrate, and a hole is formed in the substrate by removing the material in the closed-loop contour region.

[0076] Figures 8A to 8D show flowcharts for forming initial holes in a substrate according to several embodiments. The holes can be formed with a liquid jet having an internally reflected laser beam, which can create closed-loop contours or raster patterns. The holes can be made slightly smaller than the final desired dimensions and are configured to be smoothed in subsequent processes using mechanical rotary tools such as drills, reamers, milling tools, or honing tools.

[0077] In Figure 8A, operation 800 uses a liquid jet guided laser beam to form holes in the substrate, and the liquid jet guided laser beam is configured to travel in a closed-loop contour such as a circular or elliptical contour, in a rastering region that includes a helical path or multiple parallel paths, or in a combination of a closed-loop contour and a rastering region.

[0078] In Figure 8B, operation 820 uses a liquid jet guided laser beam to form holes in the substrate, and the diameter of the holes is configured to optimize the subsequent smoothing process of the inner surface of the holes.

[0079] In Figure 8C, operation 840 uses a liquid jet guided laser beam to form a hole in the substrate, and the hole diameter is configured to minimize damage to the hole edges in the subsequent process of obtaining the final hole diameter.

[0080] In Figure 8D, operation 860 uses a liquid jet guided laser beam to form holes in the substrate, with the dimensions of the holes, such as the diameter, being between 75% and 99% or between 80% and 90% of the final diameter of the holes.

[0081] In some embodiments, the liquid jet can be configured to form through-holes or blind holes, and the dimensions of the holes, such as the diameter of the holes, are configured to be optimized for high throughput while satisfying hole formation requirements, such as sidewall roughness values ​​and the absence of edge damage at the hole inlet and outlet. For example, the diameter of a circular hole can be greater than 75%, greater than 80%, greater than 85%, or greater than 90% of the final desired diameter, for example, 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.

[0082] Figures 9A-9B show the configuration of holes formed by a liquid jet according to several embodiments. Initial holes 901 can be formed in the substrate 900 using a liquid jet guided laser 916, for example, a liquid jet with an internally reflected laser beam. The initial holes can be configured to be finished by a subsequent smoothing process, such as a mechanical rotation process. For example, the process of forming initial holes in the substrate is optimized to achieve high throughput so that hundreds or thousands of holes can be efficiently drilled in the substrate.

[0083] Figure 9A illustrates the process of forming an initial hole 901 by a liquid jet 916 removing substrate material from one side of the substrate 900. For example, the liquid jet 916 can repeatedly move in multiple passes along a circular contour having a diameter 906 of the initial hole. This process continues until the initial hole fluidly connects both sides of the substrate. One or more sensors can be positioned from one or both sides of the substrate (e.g., from the substrate side opposite the liquid jet guide laser head) to detect the completion of the through-hole. After confirming the detection signal from the sensors, the liquid jet continues several more passes along the circular contour to ensure that the liquid jet completely penetrates the substrate.

[0084] After forming the initial holes, the liquid jet can move to other locations on the substrate to form subsequent holes.

[0085] Figures 9B(a) to 9B(c) show another process for forming a through-hole 901 in the substrate 900. In liquid jet guided laser processes, the process speed generally decreases as the working depth increases, so it is sometimes desirable to process the workpiece from two opposing sides rather than from one side. Drilling a hole in 12 mm thick material can take, for example, more than 180 seconds or even more than 240 seconds. A preferred method may be to first drill a blind hole to a depth of 6 mm, then rotate the workpiece 180 degrees and drill a hole on the opposite side of the blind hole, and connect them fluidly. This can reduce the overall processing time to less than 90 seconds or less than 60 seconds.

[0086] Figure 9B(a) shows a first step in rapidly machining at least one blind hole 934 within a first surface of the substrate 900 by irradiating with a liquid jet guide laser 916. The liquid jet 916 can repeatedly move in multiple passes of the rasterizing pattern within a circular contour having a diameter 906 of the initial blind hole 934. The depth of the blind hole 934 can be between 30% and 70% of the thickness of the substrate 900, for example, between 40% and 60% of the thickness of the substrate 900. After forming the initial blind hole, the liquid jet can move to another location on the substrate to form the next blind hole. As shown in the figure, the liquid jet has completed the formation of two blind holes on the left and is proceeding with the process of forming a third blind hole. The liquid jet then moves to the right to form the next blind hole.

[0087] Figure 9B(b) shows the second step of rotating the substrate 900 so that the second surface opposite the first surface of the substrate 900 faces the liquid jet guide laser head. The already fabricated blind portion of the blind hole 934 from the first step is aligned, for example, using an alignment module, so that the central axis of the blind hole 934 and the axis of the liquid jet guide laser 916 are the same. Next, the liquid jet guide laser 916 is irradiated, for example, by turning on the laser source to generate an internally reflected laser beam in the liquid jet, to rapidly machine the remaining portion of the blind hole 934 and remove all remaining substrate material. As shown, the liquid jet has completed the formation of the two through holes on the left by fabricating another portion on the opposite side that is fluidly connected to the existing blind holes. The liquid jet is proceeding with the process of forming a third blind hole configured to fluidly connect to the blind hole on the opposite side.

[0088] Figure 9B(c) shows that after the material in the through-hole of the substrate is completely removed by the liquid jet, a through-hole 901 is formed that fluidly connects the first and second surfaces of the substrate 900. One or more sensors can be used to detect when the formation of the through-hole 901 is complete. The liquid jet can then move to the right to form the next hole to connect to the existing blind hole on the opposite side.

[0089] In some embodiments, a liquid jet can be used to form blind holes, for example, holes that do not connect two opposing surfaces of a substrate. A liquid jet can be used to form two opposing blind holes, for example, two opposing holes that are not connected to each other.

[0090] The diameter of the initial hole 901 can be configured to optimize the throughput of the final hole formation. For example, in high-throughput liquid jet processes (e.g., using high laser power), the initial hole can be made as large as possible to minimize the processing time of the mechanical rotary tool. Therefore, by applying a mechanical rotary tool, the core hole 901 can be quickly finished to the desired final hole diameter. Since all the heavy work related to material removal has already been done by the liquid jet guided laser 916, the mechanical tool only needs to remove a small portion of the material. For example, the diameter of the initial through-hole can be set to 0.40 mm for a final hole diameter of 0.45 mm, and the mechanical tool only needs to remove substrate material between 0.40 and 0.45 mm.

[0091] To improve throughput in a low-speed mechanical tooling process, two mechanical tools can be used to simultaneously finish the initial hole 901 to the final hole diameter. For example, the first mechanical tool can be positioned above the first surface of the substrate. The second mechanical tool can be positioned below the second surface of the substrate. The central axes of both mechanical tools are the same. Both mechanical tools can be held at a constant distance from each other along their central axes. The substrate can move while oscillating up and down along the axes of both mechanical tools, or both mechanical tools can move while oscillating up and down simultaneously along the central axis of the core hole.

[0092] Since mechanical tools typically have a constant material removal rate based on rotations per minute and a feed rate perpendicular to the substrate, two mechanical tools can remove more material in a shorter time. Up-and-down oscillating motion may be necessary to remove substrate material from the bore. Alternatively, the first and second mechanical tools can move independently of each other along the central axis of the core hole 1217, as desired, for an efficient removal process, as long as their movements do not collide on the central axis of the hole.

[0093] Figures 10A to 10C show flowcharts for forming initial holes in a substrate according to several embodiments. In Figure 10A, operation 1000 uses a liquid jet guided laser beam to form through holes in the substrate, the liquid jet guided laser beam is configured to travel in multiple passes along a closed-loop contour, and after the through holes are formed, the material within the closed-loop contour is removed.

[0094] In Figure 10B, operation 1020 uses a liquid jet guided laser beam to form a through-hole in the substrate, and the liquid jet guided laser beam is configured to travel through multiple paths in a rasterized configuration inside a closed-loop contour.

[0095] In Figure 10C, operation 1040 uses a liquid jet guided laser beam to form a first blind hole in the substrate, configured to travel in multiple passes along a closed-loop contour or in a rasterized configuration inside the closed-loop contour. Operation 1050 optionally inverts the substrate to form a second blind hole from the opposite side of the substrate and aligns the second blind hole with the first blind hole. The second blind hole can be connected to the first blind hole to form a through hole through the substrate.

[0096] In some embodiments, the substrate can be heated to improve the throughput of the liquid jet process. Since the liquid jet process is a laser ablation process, such as material removal using laser power, a high-temperature substrate can speed up the laser ablation process. Also, in a liquid jet process, the substrate may be rapidly cooled by the flow of liquid. Therefore, when moving the liquid jet to cut material, for example, along a circular contour, the substrate can be significantly cooled before the liquid jet returns.

[0097] Figures 11A to 11D show configurations for heating a substrate to speed up the liquid jet guided laser hole formation process according to several embodiments. A hole 1101 can be made in the substrate 1100 by irradiating it with a liquid jet guided laser 1116. If the substrate is thin, such as less than a few millimeters, the liquid jet guided laser 1116 can cut the hole in a few passes, such as less than 15 passes or less than 10 passes. If the substrate is very thick, such as more than 5 mm, or more than 10 mm, or more than 15 mm, a considerably larger number of passes, such as more than 50 passes or more than 100 passes, are required.

[0098] If the hole 1101 has a larger shape, such as a large closed-loop contour along which the liquid jet travels to cut an elongated hole several centimeters in size, it may take several seconds for the liquid jet guide laser 1116 to complete a single pass around the hole 1101. The high speed of the liquid jet, the strong cooling effect of the process water, and the cooling effect of the coaxial flow of compressed gas allow the substrate 1100 to be cooled rapidly after the laser has passed through.

[0099] The present invention recognizes that the circumference 1101 of a small hole of a certain depth can be cut with a small amount of liquid jet guided laser pass. However, even at the same depth, if the circumference of the hole is 10 times larger, it may take two to three times the amount of liquid jet pass because it takes longer for the liquid jet guided laser 1112 to reach the same spot on the circumference of the hole 1101 again.

[0100] In some embodiments, the substrate region being machined by the liquid jet guided laser 1116 may therefore be heated by an auxiliary heating device to mitigate the cool-down effect on the machining time and the amount of liquid jet guided laser passes.

[0101] Figure 11A shows an immersion nozzle 1141 for immersing a workpiece (e.g., a substrate 1100) with hot water. The hot water flow 1141 can accelerate the hole machining process using a liquid jet. During the machining process with the liquid jet guided laser 1116, the substrate 1100 can be heated and kept warm by a liquid heating flow such as the immersion nozzle 1141. The water may have a temperature above 40°C, such as above 50°C. The water may have a temperature below 100°C, such as below 90°C. In some embodiments, the substrate can be heated to a temperature above 100°C using other liquids with higher vaporization temperatures. In some cases, it may be desirable to heat the back surface of the substrate rather than the top surface. In that case, the immersion nozzle is mounted below the substrate.

[0102] Figure 11B shows an infrared and / or induction device 1142 that heats and maintains the temperature of the substrate 1100 in the machining area to facilitate the hole machining process. The substrate may reach temperatures above 50°C, such as above 60°C. The substrate may reach temperatures below 150°C, such as below 110°C. In some cases, it may be desirable to heat the back surface of the substrate rather than the top surface. In that case, the infrared and / or induction device is mounted below the substrate.

[0103] Figure 11C shows a configuration for heating and maintaining the temperature of a substrate during a liquid jet guided laser process. The substrate 1100 can be fully 1143 or partially 1144 immersed in an immersion liquid. Examples of such immersion liquids include water and ethanol. The immersion liquid may have a temperature above 40°C, such as above 50°C. The immersion liquid may have a temperature lower than its evaporation temperature, for example, below 100°C or below 110°C in the case of water.

[0104] Figure 11D shows a configuration for heating and maintaining the temperature of a substrate during a liquid jet guided laser process. The substrate 1100 can receive a gas heating flow, such as an air tempering device 1145, such as a hot air gun directed towards the machined area of ​​the substrate 1100. The air tempering device 1145 can heat the substrate 1100 to a temperature above 40°C, such as above 50°C. The substrate temperature can be below 110°C.

[0105] Other temperatures can be achieved by the substrate to improve the liquid jet cutting process, for example, above 110°C, below 200°C. In some embodiments, the back surface of the substrate can be heated instead of, or in addition to, the top surface of the substrate. In this case, the gas heating flow is supplied from the bottom of the substrate instead of, or in addition to, the top surface of the substrate.

[0106] In some embodiments, for example, in the case of some very delicate substrate materials that are susceptible to heat-induced damage, a substrate cooling process can be applied to the substrate. For example, the liquid heating nozzle 1141, immersion liquid, and gas flow nozzle 1145 can be configured to provide a cold or low-temperature liquid or gas. For example, the cooling temperature can be below 60°C, such as below 40°C, and above -10°C.

[0107] Figures 12A to 12D show flowcharts for adjusting the substrate temperature during a liquid jet process according to several embodiments. In Figure 12A, operation 1200 heats the substrate during operation of the liquid jet guide laser beam to form holes in the substrate.

[0108] In Figure 12B, operation 1220 maintains the substrate temperature between 40 and 100°C during the operation of the liquid jet guide laser beam.

[0109] In Figure 12C, operation 1240 controls the substrate temperature during operation of the liquid jet guide laser beam to optimize the processing time for forming holes in the substrate.

[0110] In Figure 12D, operation 1260 places the substrate on a platform beneath the liquid jet guided laser head. Operation 1270 heats the substrate using at least one of a liquid stream, a gas stream, infrared or induction heating stream, or complete or partial immersion in a liquid bath. Operation 1280 operates the liquid jet guided laser head to form one or more holes in the substrate.

[0111] In some embodiments, sensors can be added to detect the progress of the liquid jet, and in particular to determine the termination point of the liquid jet process. The sensors may be located on the opposite side of the liquid jet head, for example, with a substrate placed between the liquid jet and the sensor.

[0112] Using light or an optical sensor, the presence of a liquid jet on the bottom side of the substrate can be detected when the liquid jet is positioned on the top side of the substrate. If the optical sensor detects the presence of a liquid jet or laser beam, the signal from the optical sensor may indicate that the liquid jet has penetrated the substrate. After the detection signal, several more passes of the liquid jet are made to ensure that the substrate is completely cut open.

[0113] Using an acoustic or sound sensor, when a liquid jet is positioned on the top surface of the substrate, the presence of a liquid jet on the bottom surface of the substrate can be detected. The sensor can be placed near the substrate, such as on the side or top surface. For example, when the liquid jet emerges from the substrate, such as when it penetrates the substrate, the acoustic or sensor can detect a different sound or tone than when the liquid jet is still cutting the substrate. The tone of the liquid jet may differ at the start of the liquid jet (e.g., before it cuts the substrate), when the liquid jet is cutting the substrate, and when the liquid jet has finished cutting. In this way, the progress of the liquid jet can be monitored by monitoring the tone of sound emitted as the liquid jet interacts with the substrate.

[0114] Other sensors, or combinations of sensors such as a combination of a light sensor and a sound sensor, can be used.

[0115] Figures 13A-13C show sensor configurations for a liquid jet guided laser process to detect the termination point of the liquid jet process according to several embodiments. When forming holes 1301 in the substrate 1300 with a liquid jet guided laser 1316, a constant material removal rate is applied based not only on the substrate material but also on process parameters such as the liquid jet nozzle diameter, liquid jet pressure, laser output, laser pulse length, laser frequency, feed rate, and compressed shielding gas pressure. A liquid jet guided laser system is 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.

[0116] However, factors affect the achievable cutting speed and the time required to fluidly cut a hole from the top to the bottom of the substrate. For example, heterogeneity in the substrate material can cause some areas to cut faster or slower. Also, inside the liquid jet guide laser head, there are certain parts that can wear out over time, such as the laser window that the laser beam must pass through before coupling with the liquid jet nozzle. Therefore, this laser window is replaced after a certain operating time. Sensors that detect the cutting point can be applied to speed up the entire hole drilling or projection cutting process and to detect wear on consumable parts.

[0117] A cutting optical sensor 1352 can be placed near the substrate 1300. Alternatively, or in addition, a cutting acoustic sensor 1351 can be placed near the substrate 1300. In some embodiments, both the cutting optical sensor 1352 and the cutting acoustic sensor 1351 are placed adjacent to or below the substrate 1300 in which at least one hole 1301 is machined by the liquid jet guided laser 1316. When the drilling process is initiated and the laser beam from the liquid jet guided laser 1316 is turned on, a strong plasma-induced cutting sound may be generated. Such plasma-induced sounds typically have a frequency in the same tone as the frequency of the laser beam. Such plasma-induced sounds may decrease or even disappear as the penetration depth of the liquid jet guided laser 1312 into the substrate 1300 increases. During cutting, a sharp increase in the emitted sound level may occur as the liquid jet guided laser 1316 rapidly exits the bottom of the hole 1301. In the portion of the hole 1301 that has not yet been cut, the emitted sound may disappear again. For example, during the initial cutting with the liquid jet guide laser 1316, only one-quarter of the circumference of the bore 1301 is cut open, and three-quarters of the circumference of the bore 1301 remains untouched within the same laser path. For this cut-open portion, the emitted sound can be detected by the cutting acoustic sensor 1351. For the uncut portion of the circumference of the bore 1301, the cutting acoustic sensor 1351 can detect a much lower amount of emitted sound, or no sound at all.

[0118] When the drilling process begins and the laser beam from the liquid jet guide laser 1316 is turned on, most of the laser energy is directed by the liquid jet guide laser 1316 towards the substrate 1300 through total internal reflection within the liquid jet, into the cutting area of ​​the hole 1301. The cutting light sensor 1352 can be positioned opposite the substrate 1300. That is, the substrate 1300 is positioned between the liquid jet guide laser head and the cutting light sensor 1352. When the drilling process begins, the cutting light sensor 1352 can detect if the intensity of the emitted laser light is low or if there is no emitted laser light at all. During cutting, a rapid increase in the level of emitted laser light from the liquid jet guide laser 1316 exiting the bottom of the hole 1301 may occur. In the parts of the hole 1301 that have not yet been cut, the emitted laser light may disappear again. For example, during the initial cutting with the liquid jet guide laser 1316, only one-quarter of the circumference of the hole 1301 is cut, and three-quarters of the circumference of the hole 1301 remains untouched within the same laser path. For this cut portion, the emitted laser light can be detected by the cutting light sensor 1352. For the uncut portion of the circumference of the hole 1301, the cutting light sensor 1352 can detect a very low amount of laser light, or no laser light at all.

[0119] In some embodiments, light from a light source not generated by the laser itself is coupled to the liquid jet guided laser 1316 inside the liquid jet guided laser head. Such a secondary light source can be an LED emitting a specific wavelength. The cutting light sensor 1352 can be fitted with at least one optical filter that can block the laser wavelength and allow the LED wavelength to pass through, or vice versa. During cutting, the light intensity of the LED may increase rapidly, guided by the liquid jet guided laser 1316 emanating from the bottom of the hole 1301. In parts of the hole 1301 that have not yet been cut, the light intensity of the LED may disappear again. For example, during the initial cutting by the liquid jet guided laser 1316, only one-quarter of the circumference of the hole 1301 may be cut, while three-quarters of the circumference remains untouched within the same laser path. For such cut portions, the light intensity of the LED can be detected by the cutting light sensor 1352. For the uncut portion of the circumference of hole 1301, the cut-out light sensor 1352 can detect a very low amount of LED light, or no light at all.

[0120] Figure 13C shows the amplitude behavior of the cutting optical sensor, the cutting acoustic sensor, and the emitted laser light. By applying either the cutting optical sensor 1352 or the cutting acoustic sensor 1351, the moment when the liquid jet guide laser 1316 cuts through the substrate 1300 can be precisely determined. In addition to the moment of cutting, the hole that has been completely cut in the circumferential direction can also be detected. In such cases, the emitted laser light intensity 1352 detected by the cutting optical sensor 1352 is measured along the entire machining path of the liquid jet guide laser 1316 around the circumference of the hole 1301. * The emission sound intensity 1351 detected by the cutting acoustic sensor 1351 is always high, or in the entire machining pass of the liquid jet guide laser 1316 around the circumference of hole 1301. *The voltage is always high. In some embodiments, the cutting point of the hole 1301 opened by the liquid jet guide laser 1316 is detected by a combination of a cutting optical sensor 1352 and a cutting acoustic sensor 1351. Laser on / off pattern 1311 * In relation to this, the emitted laser light intensity is 1352 * and emitted sound intensity 1351 * It can be monitored.

[0121] Before machining the hole 1301 in the substrate 1300, the laser emission of the liquid jet guide laser head is turned off. Generally, the laser emission and the water source forming the liquid column can be controlled independently. For example, water can be flowed when the laser emission is off. When the process of drilling the hole 1301 begins, the laser emission is turned on and guided onto the substrate 1300 through the liquid jet. At the moment the laser is turned on 1353, the uncut substrate 1300 forms a light barrier, so the laser light is not picked up by the cutting light sensor 1352, and therefore the detected emitted laser light intensity 1352 * The signal intensity may be lower than the signal threshold. At the moment the laser is turned on 1353, the cutting acoustic sensor 1351 can detect the sound emitted by the cutting plasma, so the detected emitted sound intensity 1355 may be higher than the signal threshold. However, as the liquid jet guide laser 1316 penetrates deeper into the substrate 1300, the emitted sound intensity 1353 may rapidly decrease and fall below the signal threshold.

[0122] At the moment of laser cutting 1354, both the emitted laser light intensity 1356 and the emitted sound intensity 1357 increase rapidly and may exceed the signal threshold. The liquid jet guided laser can remain on and perform machining over the entire circumference of the hole 1301 until the emitted laser light intensity 1356 and the emitted sound intensity 1357 remain above the signal threshold. The laser is then switched off at the moment of laser off 1354. *Then, both the emitted laser light intensity 1356 and the emitted sound intensity 1357 may decrease sharply again and fall below the signal threshold. Emitted laser light intensity 1352 * and emitted sound intensity 1351 * By monitoring both, a secure method can be provided to detect complete cutting of holes 1301 in a wide variety of substrates and substrate 1300 materials, as well as in different hole shapes such as circular holes, square holes, elliptical holes, elongated holes, conical holes, narrow high aspect ratios, and other free shapes.

[0123] Figures 14A-14B show flowcharts for detecting the termination point of a liquid jet process according to several embodiments. In Figure 14A, operation 1400 turns on the laser emission to generate a laser beam that reflects internally within the liquid column to form a hole through the substrate. In operation 1410, a signal is received from at least one of the optical sensor or acoustic sensor indicating that the hole has completely penetrated the substrate. In operation 1420, the laser emission is turned off.

[0124] In Figure 14B, operation 1440 detects the penetration of a liquid column with an internally reflected laser beam generated above the substrate, and the detection includes receiving signals from an optical sensor and an acoustic sensor. Operation 1450 allows the liquid column with the internally reflected laser beam to travel for a predetermined time. Operation 1460 turns off the laser emission.

[0125] In some embodiments, an electrical discharge machining (EDM) process can be used to form initial holes in the substrate. For example, the EDM process can be used to enlarge initial holes formed by a liquid jet. Alternatively, the EDM process can be used to form initial holes without using a liquid jet.

[0126] Figures 15A to 15D illustrate processes for forming initial holes using liquid jets and electrical discharge machining according to several 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 receive an EDM electrode, such as a wire 1507 connecting the two terminals of an EDM power supply 1535.

[0127] Figure 15B shows a hole enlargement process 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 surface of the enlarged hole, such as by smoothing it. The mechanical rotary tool can provide a much lower roughness value compared to the EDM process.

[0128] The EDM process can be a wire-based EDM process that uses a thin wire to erode the material inside the diameter of the hole 1501. In such a case, the diameter 1508 of the EDM electrode is much smaller than the diameter 1501 of the core hole, and all the material inside the diameter of the hole 1501 can be removed by performing a circular machining operation to cut out a cylindrical pin, or by performing a helical operation by the EDM process, or by combining circular and helical machining operations.

[0129] For example, a roller wire can pass through a hole formed by a liquid jet and can be 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 by a discharge process, for example, from the wire EDM to the substrate. The wire can be moved along a closed-loop contour, such as a circular contour, to enlarge the initial hole to the desired size.

[0130] Figure 15C shows a hole enlargement process using a sink electrode-based EDM process, which uses a hole-shaped electrode to erode the material inside the diameter of hole 1501. After enlarging the hole to a size slightly smaller than the final diameter, for example, the enlarged hole can be finished, such as by smoothing the surface of the enlarged hole using a mechanical rotary tool. One end of the EDM electrode can be coupled to an EDM power supply. In such cases, the EDM electrode 1507 * This can be made slightly smaller than the initial pore formed by the liquid jet.

[0131] Figure 15D shows the configuration of a hole formed by an EDM process to enlarge an initial hole formed by a liquid jet. The EDM hole may have a diameter of 1508, which is slightly smaller than the final diameter of 1502. The EDM hole can be subjected to mechanical tools to finish the hole to a desired final hole with a final diameter of 1502 having the desired quality and roughness values.

[0132] Figures 16A-16B show processes for forming initial holes using electrical discharge machining according to several embodiments. In Figure 16A, the EDM process may be a sink electrode-based EDM process in which electrode 1607 is applied to the substrate to erode the material in the substrate. The electrode is connected to a terminal of the EDM power supply 1635. The substrate is connected to another terminal of the EDM power supply.

[0133] Figure 16B shows the configuration of the initial hole formed by the EDM process. The EDM hole may have a diameter of 1608, which is slightly smaller than the final diameter of 1602. The EDM hole can be subjected to mechanical tools to finish the hole to a desired final hole with a final diameter of 1602 having the desired quality and roughness values.

[0134] Figures 17A-17C show flowcharts for forming holes using an EDM process in several embodiments. In Figure 17A, operation 1700 forms a hole through the substrate using a liquid jet guided laser beam. Operation 1710 enlarges the hole using wire electrical discharge machining. Operation 1720 smooths the enlarged hole using a mechanical rotary tool.

[0135] In Figure 17B, operation 1740 involves forming a hole in the substrate using electrical discharge machining. Operation 1750 involves smoothing the hole using a mechanical rotary tool.

[0136] In Figure 17C, operation 1770 involves forming a hole in the substrate using a liquid jet guided laser beam or electrical discharge machining. Operation 1780 involves smoothing the hole using a mechanical rotary tool.

[0137] In some embodiments, the liquid jet can move from place to place on the substrate to form a number of initial holes, and then transport the substrate to a mechanical rotary tool head for finishing the holes. The movement of the liquid jet can be achieved by an operating mechanism such as an xy or xyz operating table for moving the liquid jet guide laser head that generates the liquid jet.

[0138] Figures 18A to 18B show configurations for forming multiple holes in a substrate using a liquid jet, according to several embodiments. Figures 18A(a) and 18A(b) show a configuration for forming through holes in a substrate from one side using a liquid jet. Figures 18B(a) and 18B(b) show a configuration for forming blind holes in a substrate from one side using a liquid jet, then inverting the substrate and completing the blind holes into through holes from the opposite side of the substrate.

[0139] In Figure 18A(a), a through-hole 1801 can be formed in the substrate 1800 using a liquid jet 1816, for example, a liquid jet generated from a liquid jet guide laser head having an internally reflected laser beam confined within the boundary of the liquid jet. The liquid jet can travel along multiple paths along a closed-loop contour, such as along a circular contour, to cut a cylinder with a diameter similar to the diameter of the desired hole. Alternatively, instead of creating a cylinder, the liquid jet can be rasterized within the circular contour, such as creating a spiral path or multiple parallel lines, to remove material from the hole. In Figure 18A(b), the liquid jet moves to another location on the substrate to form the next through-hole.

[0140] The through-holes in the substrate may be initial holes, and for example, the through-holes may then be finished by, for example, a subsequent mechanical rotary tool to smooth the walls of the holes.

[0141] In some embodiments, initial holes can be formed by a combination of liquid jet and EDM process. For example, a liquid jet can form one or more initial holes with a diameter suitable for the EDM electrode. For instance, in an EDM process based on a sink electrode, the initial holes formed by the liquid jet can be slightly larger than the size of the sink electrode. When using an EDM process based on a wire electrode, the initial holes can be made large enough for the wire to pass through. Alternatively, holes can be formed by the EDM process without any initial holes. For example, a sink electrode can be placed near the substrate, the EDM power can be turned on, and the material can be removed from the electrode to form holes.

[0142] In any case, the initial holes formed by the liquid jet, a combination of the liquid jet and an EDM electrode, or an EDM electrode may be sized to be suitable for subsequent finishing processes using mechanical rotary tools.

[0143] In some embodiments, all through-holes can be formed in the substrate by a liquid jet. The substrate can then be moved to an EDM system, which may be configured to continue processing the through-holes formed by the liquid jet. After the finishing process, the substrate can be moved to a mechanical rotary system, where a mechanical rotary tool can be used to finish the initial holes.

[0144] In Figure 18B(a), a liquid jet 1816 may be used to form blind holes 1834 in the substrate 1800. The liquid jet can form blind holes at a certain location on the substrate. The liquid jet then moves to another location and forms another blind hole. This process continues until all blind holes have been formed on the substrate.

[0145] In Figure 18B(b), the substrate is inverted, so that, for example, the opening side of the blind hole is opposite the liquid jet. The liquid jet can be aligned with the blind hole, for example, by an alignment module. After alignment, the liquid jet can create another blind hole on the opposite side of the aligned blind hole. The liquid jet can further connect the two blind holes to form a through hole, thereby connecting the two faces of the substrate.

[0146] After forming a through-hole, the liquid jet can move to another location on the substrate and create a blind hole that connects to an existing blind hole on the opposite side, thereby forming the next through-hole.

[0147] The through-holes in the substrate can be left as initial holes, and for example, the through-holes can then be finished by, for example, a subsequent mechanical rotary tool to smooth the walls of the holes.

[0148] Figure 19 shows a closed-loop process for drilling holes with a liquid jet guided laser according to several embodiments. A laser machining process for drilling a bore, or a core hole in a bore, can be initiated. The laser machine tool can move the liquid jet guided laser head to a first machining position among a plurality of machining positions. The laser process can be started. When at least one sensor detects an opening signal, the laser process can travel a defined amount of additional safety passes. After traveling the defined amount of safety passes, the laser process stops, and the laser machine tool can move the liquid jet guided laser head to the next machining position among the plurality of machining positions. This loop continues and can be completed when the last machining position among the plurality of machining positions is finished.

[0149] In operation 1900, the substrate is placed on the platform. A liquid jet can be formed using the nozzle of the liquid jet guide laser head. The nozzle is also aligned with the laser beam, and an internally reflected laser beam can be obtained within the liquid jet. In operation 1910, the liquid supply is turned on to form a liquid column. In operation 1920, the liquid jet guide laser head is moved to a first position on the substrate. In operation 1930, the laser emission is turned on to generate a laser beam internally reflected within the liquid column to form a first hole through the substrate. In operation 1940, after confirming the cutting signal from the sensor, an additional laser path is optionally run to ensure the substrate is cut open. In operation 1950, the laser emission is turned off. In the subsequent operation 1960, the next through hole is formed at the next location.

[0150] In some embodiments, the present invention discloses a subsequent process for finishing an initial hole formed by a liquid jet guided laser system, such as smoothing the sidewalls of the initial hole and obtaining a desired final diameter of the hole, while ensuring that the entrance and exit edges are not damaged. The finishing process can be carried out using a mechanical rotary tool such as a drill bit, side mill bit, end mill bit, reamer, or honing tool that can smooth the sidewalls of the initial hole. By using a rotary tool with a diameter equal to the final hole diameter, the initial hole can be adjusted to the final diameter while simultaneously smoothing the sidewalls. Furthermore, by using a rotary tool with a rounded tip, such as an elliptical tip, it is possible to avoid the abrupt onset of contact between the rotary tool and the surface of the hole entrance, thereby adjusting the edge of the hole entrance to obtain a sharp edge at the entrance of the hole without edge deterioration such as chipping or unevenness. In some embodiments, the substrate can be inverted, and the rotary tool can form a sharp edge, such as an undamaged edge, at the other end of the through hole, such as the hole exit.

[0151] A mechanical rotary process may include a cutting process or a honing or grinding process. A cutting process may include one or more sharp edges on the cutting tool to separate the material from the substrate. For example, the tip of a drill bit may have a conical cutting edge for removing material in the axial direction. A drill bit may have sharp cutting edges on the flute portion of the drill bit to remove material from the side walls of the drilled hole. In a honing process, the honing tool may include one or more rough surfaces for removing material from the substrate by the honing process.

[0152] Mechanical rotary processes can include drilling, boring, reaming, milling, or honing processes. Drilling is a cutting process in which a circular hole can be cut into a substrate using a drill bit. Mechanical rotary tools such as drill bits can be used in drilling processes to cut material. Drilling processes can be performed with or without an initial hole. If an initial hole exists, the material can be removed from the side walls of the initial hole while the drill bit is rotated. If there is no initial hole, the drill bit can bite into the substrate and form a circular hole. A mechanical rotary head can be used to hold and rotate the rotary tool.

[0153] Boring is also a cutting process that uses a single-point cutting tool, boring head, or boring bar to enlarge existing holes in a substrate. The boring process is similar to drilling when there are pre-existing holes, as it is performed to enlarge and smooth pre-existing holes in the substrate. The boring process is different from drilling when there are no pre-existing holes, as it is performed to create pre-existing holes in the substrate.

[0154] Reaming is also a cutting process, where a smooth inner wall can be formed in an existing hole in a substrate using rotary cutting or honing tools such as a reamer or reamer bit. Like drill bits and boring burs, reamers also remove sidewall material from the initial hole. However, reamers remove significantly less material than drill bits (for example, the material removal rate is slower). Reamers are typically used to create a smooth wall within the initial hole.

[0155] Honing is a polishing machining process in which a honing tool or honing tool is used to polish a grinding wheel or grinding wheel, thereby creating a precise surface on a metal workpiece. Honing tools can include diamond-polished boring bars. The tool is extendable to compensate for wear on the diamond sleeve.

[0156] In some embodiments, the rotary tool can be selected according to 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. Reamers and honing tools are the most precise of the three types of rotary cutting or honing tools and can produce the smoothest surface.

[0157] Figures 20A to 20B show processes for forming holes according to several embodiments. Figures 20A(a) to 20A(c) show a process using a mechanical rotary tool when there are no initial holes. For example, precision holes 2001 in a ceramic substrate 2000 for gas distribution plates and homogenization plates can be formed by sequentially drilling each hole 2001 with a mechanical rotary tool 2020 such as a drill bit when there are no initial holes. A typical substrate 2000 for a gas distribution or homogenization plate is made of single-crystal silicon material and may have 1000 to 2000 high-aspect-ratio precision holes 2001 with a hole diameter of 0.2 to 0.8 mm and a hole depth of 10 to 15 mm to form a fluid connection between the front and back sides of the substrate. To achieve the desired hole diameter, a rotary tool of the same diameter is typically used. Requirements for holes in a gas distribution or homogenized plate may include the inner wall of each hole being smooth and mirror-like to avoid the adhesion of unwanted particles that could potentially contaminate the actual product wafer through which the gas passing through these holes 2001 is guided.

[0158] The drilling tool 2020 can typically achieve the desired mirror-like surface finish on the inner wall of the hole. To ensure stable and reproducible gas distribution, both the entrance and exit of the hole must have sharp edges free from circumferential damage. Since the substrate 2000 may be a brittle substrate such as single-crystal silicon, mechanical drilling tools can increase the risk of material chipping at the entrance 2061 and at the exit 2062.

[0159] Furthermore, when processing ceramic substrates 2000, the drilling tool experiences significant wear, particularly when processing materials such as silicon or silicon carbide, resulting in a shortened tool life. In terms of throughput, drilling each hole 2001 can take 3-4 minutes. If a drill bit breaks at, for example, 1480 holes in a substrate requiring 1500 holes, the entire substrate 2000 may have to be discarded, resulting in the loss of many hours of machining work.

[0160] Figures 20B(a) to 20B(c) show the mechanical rotary tool 2020 when an initial hole is present. * The process using this method is shown. An initial hole 2001 can be formed in the 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 roughness of the initial hole surface, such as 2 to 10 times, 2 to 6 times, or 2 to 4 times. Therefore, the rotary tool can smooth the sidewall surface from the initial hole to the final hole without removing too much sidewall material.

[0161] Rotary Tools 2020 * For example, by having a tool tip 2023, such as a tip that allows the rotary tool to contact the upper edge from the sidewall surface (e.g., contacting the upper edge at an angle not perpendicular to the top surface of the substrate), the potential material chipping at the upper edge can be reduced. In this way, with minimal material removed from the tool tip and sidewall, the upper edge of the hole, particularly at the upper edge, is less prone to chipping and damage 2061. * The shape may no longer be irregular, such as lacking certain features. Since the rotating tool is continuous, it can penetrate the hole from above.

[0162] In some embodiments, for example, a rotary tool 2020 * The material is removed from the substrate before the through hole is completed, and then the substrate can be inverted, for example, by turning it so that the bottom surface of the substrate faces the rotary tool. The rotary tool then rotates and moves downward, and the hole can be finished from the new side, for example, the bottom side which is now the top. The tip of the tool can cause chipping or damage to the bottom edge.* It can be eliminated.

[0163] Figures 21A to 21C show configurations of mechanical rotary tools according to several embodiments. Mechanical rotary tools can be used for finishing holes formed by liquid jet processes, a combination of liquid jet processes and EDM processes, or EDM processes. To remove any remaining material between the core hole and the final hole diameter, the mechanical tool can be rotated at speeds exceeding 20,000 RPM. In some embodiments, the mechanical tool can be rotated at 40,000 to 120,000 RPM (rotations per minute).

[0164] Based on the substrate material, the mechanical rotary tool 2120 for finishing core holes to the final hole diameter may have different shapes for optimal material removal, desired hole wall surface finish, and tool life. The mechanical rotary tool can be a drill bit, reamer, milling tool, or honing tool.

[0165] Figures 21A(a) to 21A(c) show various tool tips for rotary tools that may have tip parameters optimized for core hole finishing processes. The tool tip 2163 or 2163 of the mechanical tool 2120. * The tip may be flat, or it may have a tip optimized to allow for soft self-centering of the tool toward the central axis of the core hole. The tool tip may have a conical, hemispherical, or other suitable convex shape.

[0166] Figures 21B(a) to 21B(c) show the main cutting surface 2164 and the secondary cutting (or non-cutting) surface 2164. *Various configurations of the rotary tool body are shown, including those having the following features. The main 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 main cutting surface of the tool can be made of a diamond material such as a synthetic diamond material. Examples of such synthetic diamond materials include polycrystalline diamond (PCD), monocrystalline diamond (or single-crystal diamond SCD), or diamond particles in a binder material.

[0167] In some embodiments, the rotary tool has a secondary cutting surface or non-cutting surface 2164 made from a different material such as carbide, hard metal, boron carbide, silicon nitride, or cubic boron nitride. * It may have a main cutting surface 2164 made of diamond material, connected to the main cutting surface.

[0168] In some embodiments, the rotary tool may have a main cutting surface 2164 made of diamond material, the main cutting surface of the tool extending over the tool axis.

[0169] Figures 21C(a) to 21C(c) show various tool axis configurations for rotary tools. Typically, a rotary tool may have the same diameter across its primary and secondary cutting surfaces. In some embodiments, a rotary tool may have a second tool diameter to optimize various parameters of the core hole finishing process. For example, a rotary tool may have a primary cutting surface with a first tool diameter connected to a secondary cutting surface with a second tool diameter, such as a concave diameter of 2165.

[0170] Figures 22A-22C show flowcharts for finishing holes in a substrate according to several embodiments. In Figure 22A, operation 2200 smooths the holes in the substrate using a mechanical rotary tool. In Figure 22B, operation 2220 rotates the mechanical rotary tool while it is inserted into the holes in the substrate, so that the holes have a diameter optimized for high throughput and minimal edge damage.

[0171] In Figure 22C, operation 2240 involves rotating a mechanical rotary tool while inserting it into a hole in the substrate. The mechanical rotary tool may have a rounded tip. The mechanical rotary tool may have a tip-like portion configured to smooth the inner surface of the hole. The mechanical rotary tool may have a base-like portion having a smaller diameter than the tip-like portion.

[0172] In some embodiments, gas distribution or uniform plates can be formed by a combination of liquid jet processes and mechanical rotary processes. For example, a core hole can be formed first using a liquid jet guided laser, and then the core hole can be finished to the final hole using a mechanical rotary tool. By irradiating with a liquid jet guided laser, deep, high-quality micro-holes can be drilled quickly without tool wear. To form a core hole in the substrate, the liquid jet guided laser can perform a circular machining operation to cut out a cylindrical pin, or it can perform a helical operation or a combination of circular and helical machining operations to remove all material within the diameter of the core hole.

[0173] The surface roughness of the sidewalls of holes can reach values ​​of less than Ra 1um or even less than Ra 0.3um. However, workpieces such as gas distribution plates and substrates for homogenization plates used in semiconductor processing equipment may require a sidewall roughness value of less than Ra 0.1um. Mechanical drilling tools can achieve a roughness value of less than Ra 0.1um, but the drilling process is slow because the drill must be moved gently in and out of the substrate material to avoid damage to the hole entrance and exit in the form of scraped substrate material. In such a drilling process, it may take 3 to 5 minutes to drill just one hole. Also, the drilling tool may wear out quickly after drilling only a few hundred holes.

[0174] In some embodiments, a liquid jet guided laser is used to rapidly remove most of the material from the hole, thereby performing all the heavy labor related to material removal quickly and without tool wear. The liquid jet guided laser can be used to rapidly form a core hole 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 core hole with a diameter of 0.40 mm. Depending on the parameters of the liquid jet guided laser, such a core hole can be formed in, for example, 30 to 60 seconds.

[0175] After the hole is formed, a mechanical tool can be applied to remove any remaining material. By using a tool with a diameter matching the final hole diameter, the core hole diameter can be enlarged to the final diameter by removing only a small amount of material. This allows the feed rate of the mechanical tool along the central axis of the core hole to be significantly faster compared to drilling the final hole through the entire bulk substrate material. Such a finishing step can be completed in, for example, 30 to 60 seconds, reducing the overall time required to drill the desired hole diameter with the desired quality and roughness by more than 50%.

[0176] In some embodiments, depending on the preferred material flow and cycle time in the production equipment, the operation of forming core holes with an inkjet guide laser and finishing the core holes to the final diameter with a mechanical tool can be performed on the same machine (inkjet guide laser + mechanical drill) or on two separate machines.

[0177] In some embodiments, the initial holes can be formed by an EDM process, such as a combination of a liquid jet and an EDM process, or by an EDM process alone. For example, the initial holes can be formed using a combination of a wire-based electrode EDM process and a liquid jet process. Alternatively, the initial holes can be formed by a sink electrode based on an EDM process without performing a liquid jet process.

[0178] After forming an initial hole by either a liquid jet process, an EDM process, or a combination of both, the initial hole can be finished by smoothing it to the final dimensions using a mechanical rotary tool, thereby obtaining a final hole with the desired diameter, quality, and roughness value.

[0179] In some embodiments, the mechanical rotary tool can be configured to smooth the initial hole from one side, sequentially from two sides, or simultaneously from two sides. The initial through-hole can also be formed from one side or from two sides using a liquid jet.

[0180] In some embodiments, the hole finishing process can be optimized based on the initial hole formation, the substrate material, and the requirements of the final hole. To achieve an optimal hole, for each different core hole finishing strategy, the quality of the sidewalls must be considered, as well as the quality of the inlet and outlet sides. For example, the core hole can fluidly connect the upper and lower sides of the substrate. By applying mechanical tools, the core hole can be finished to the desired final hole diameter. The mechanical tool may have a tool diameter equal to or slightly smaller than the desired final hole diameter.

[0181] In some embodiments, the core hole can be a blind hole covering more than 30% of the substrate depth, for example, more than 50% but less than 95% of the substrate depth. By applying a mechanical tool, the core hole can be finished to the desired final hole diameter. The mechanical tool can enter the substrate from the open side of the core hole. The mechanical tool can create the final projection from the underside of the substrate. The mechanical tool may have a tool diameter equal to or slightly smaller than the desired final hole diameter.

[0182] In some embodiments, the core hole can be a blind hole covering more than 30% of the substrate depth, for example, more than 50% but less than 95% of the substrate depth. A mechanical tool can enter the substrate from the blind side of the core hole and cut through the entire material until it reaches the open portion of the core hole. The core hole can then be finished to the desired final hole diameter by applying the mechanical tool. The mechanical tool may have a tool diameter equal to or slightly smaller than the desired final hole diameter.

[0183] In some embodiments, the core hole consists of two blind holes, each on the opposite side of the substrate, with the central axis of each core hole being essentially coaxial through the substrate. Each blind hole can cover more than 30% but less than 45% of the substrate depth. A mechanical tool can enter the substrate from either open side of the core hole. The mechanical tool can create a final projection 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 suitable for very brittle substrate materials that are susceptible to chipping when the mechanical tool enters either side of the substrate surface. The critical projection is created inside the substrate where the risk of chipping is low.

[0184] Figures 23A to 23B show a process for finishing an initial through-hole according to several 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 can be formed by a liquid jet process and has a diameter 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 open the initial through-hole having a final diameter. The rotary tool can be withdrawn from the substrate, for example, to move to another through-hole.

[0185] Figures 23B(a) to 23B(e) show alternative processes for the rotary tool 2320 to finish or smooth an initial through-hole in the substrate. The rotary tool can smooth a portion of the through-hole from the first side of the substrate. The rotary tool can then be withdrawn from the substrate. The substrate can then be inverted 2366. The rotary tool can smooth the remaining portion of the through-hole from the second side of the substrate, opposite to the first side. The rotary tool can then be withdrawn from the substrate.

[0186] Figures 24A–24C illustrate a process for finishing an initial one-sided blind hole according to several embodiments. Figures 24A(a)–24A(b) show a rotary tool 2420 approaching a blind hole 2434 from the opening side of the blind hole. The blind hole 2434 can be formed in the substrate 2400 by a liquid jet process and has a diameter slightly smaller than the diameter of the rotary tool 2420. The rotary tool can rotate and enter the initial blind hole 2434 to smooth the sidewall of the initial blind hole and also to open the initial blind hole having a final diameter. The rotary tool can be withdrawn from the substrate to move, for example, to another blind hole.

[0187] Figure 24B shows another process for finishing a blind hole, where a rotary tool 2420 approaches the blind hole 2434 from the blind side of the blind hole, for example, from the opposite side of the opening of the blind hole. The blind hole 2434 can be formed in the substrate 2400 by a liquid jet process and has a diameter slightly smaller than the diameter of the rotary tool 2420. The substrate is then inverted so that the blind side of the blind hole is presented to the rotary tool. The rotary tool rotates and can cut into the substrate from the aligned position, which is the center of the blind hole. The rotary tool can then form the final through hole, smooth the side walls of the hole, and also form an initial hole with the final diameter. The rotary tool can be withdrawn from the substrate to move to, for example, another blind hole.

[0188] Figures 24C(a) to 24C(e) show alternative processes for the rotary tool 2420 to finish or smooth the initial blind holes in the substrate. The rotary tool can smooth a portion of the blind holes from the opening side of the blind holes. The rotary tool can then be withdrawn from the substrate. The substrate can then be inverted 2466. The rotary tool can smooth the remaining portion of the blind holes from a second side of the substrate, opposite to the opening side of the blind holes. The rotary tool can then be withdrawn from the substrate.

[0189] Alternatively, a rotary tool can first smooth a portion of the blind hole from the opposite side of the opening.

[0190] Figures 25A–25B illustrate a process for finishing initial double-sided blind holes according to several embodiments. Figures 25A(a)–25A(c) show a rotary tool 2520 approaching a blind hole 2534 from one of its two opening sides. The blind hole 2534 can be formed in the substrate 2500 by a liquid jet process and has a diameter slightly smaller than the diameter of the rotary tool 2520. The rotary tool can rotate and enter the initial blind hole 2534 to smooth the sidewalls of the initial blind hole and also to open the initial blind hole to have a final diameter. The rotary tool can be withdrawn from the substrate, for example, to move to another blind hole.

[0191] Figures 25B(a) to 25B(e) show alternative processes for the rotary tool 2520 to finish or smooth the initial blind holes in the substrate. The rotary tool can smooth a portion of the blind hole from either of the two opening sides of the blind hole. The rotary tool can then be withdrawn from the substrate. The substrate can then be inverted 2566. The rotary tool can smooth the remaining portion of the through hole from a second side of the substrate, opposite to the opening side of the blind hole. The rotary tool can then be withdrawn from the substrate.

[0192] In some embodiments, two mechanical tools can be used to finish a core hole to its final diameter simultaneously. The first mechanical tool can be positioned above the first surface of the substrate. The second mechanical tool can be positioned below the second surface of the substrate. The central axes of both mechanical tools are the same. Both mechanical tools can be held at a constant distance from each other along their central axes. The substrate can move while oscillating up and down along the axes of both mechanical tools, or both mechanical tools can move while oscillating up and down simultaneously along the central axis of the core hole. Since the mechanical tools typically have a constant material removal rate based on the rotations per minute and the feed rate perpendicular to the substrate, more material can be removed by the two mechanical tools in a shorter time. The up and down oscillating motion may be necessary to remove the substrate from the hole. Alternatively, the first and second mechanical tools can move independently along the central axis of the core hole, as desired, for an efficient removal process, as long as their movements do not collide along the central axis of the core hole.

[0193] Figures 26A-26B illustrate the process for finishing a hole using two mechanical rotary tools according to several embodiments. Figures 26A(a)-26A(d) show two rotary tools 2620 and 2620 on two opposing sides of a through hole 2601 in a substrate 2600. * This illustrates the process. The through-hole 2601 can be formed by a liquid jet process and has a diameter slightly smaller than the diameter of the rotary tool 2620. The rotary tool can rotate and enter the initial through-hole 2601 to smooth the side walls of the initial through-hole and to create an initial through-hole having the final diameter. Each rotary tool can move independently or simultaneously. For example, two rotary tools can be vibrated back and forth from the substrate. The distance between the two rotary tools may be constant; for example, the two rotary tools vibrate while separated by a fixed distance. The distance between the two rotary tools can be varied, for example, from a very close distance to a very far distance from each other. The rotary tools can be withdrawn from the substrate to move to another through-hole, for example.

[0194] Figures 26B(a) to 26B(d) show two rotary tools 2620 and 2620 facing two opposing sides of the blind holes 2634 on both sides of the substrate 2600. * This illustrates that each rotary tool can rotate into the initial blind hole 2601 to smooth the side walls of the initial blind hole and also to create an initial blind hole having a final diameter.

[0195] Figures 27A to 27C show flowcharts for finishing initial holes in a substrate according to several embodiments. In Figure 27A, operation 2700 involves rotating a mechanical rotary tool while inserting it into the through-hole in the substrate. The mechanical rotary tool enters the through-hole from a first side to completely smooth the surface of the through-hole. Alternatively, the mechanical rotary tool enters the through-hole from a first side to smooth a portion of the surface of the through-hole, and then enters the through-hole from the opposite second side to smooth the surface of the remaining portion of the through-hole.

[0196] In Figure 27B, operation 2720 involves rotating a mechanical rotary tool while inserting it into the blind hole in the substrate. The mechanical rotary tool enters the blind hole from a first side to completely smooth the surface of the through hole. Alternatively, the mechanical rotary tool enters the blind hole from a first side to smooth a portion of its surface, and then enters the through hole from the opposite second side to smooth the remaining portion of its surface.

[0197] In Figure 27C, operation 2740 involves rotating two mechanical rotary tools while inserting them into holes in the substrate. Each mechanical rotary tool enters the hole independently of the others. Alternatively, each mechanical rotary tool enters simultaneously from opposite directions and is then moved in one direction while maintaining a constant distance between them.

[0198] In some embodiments, the temperature of the mechanical rotary tool can be adjusted to prevent overheating, for example, due to the rotational motion that removes material from the sidewalls of holes in the substrate. Furthermore, the mechanical rotary tool can be exposed to a lubricant, for example, to prevent excessive wear of the rotary tool. The temperature of the rotary tool can be kept constant, for example, by using a flow of liquid or gas or an immersion bath to cool the rotary tool to ambient temperature.

[0199] Mechanical tools can be actively cooled before, during, and after the material removal process. Active cooling can be performed using a coolant such as water, or a gas such as air or CO2. The cooling medium can be supplied to the outside of the mechanical tool as an axial, radial, or angular flow.

[0200] In some embodiments, the mechanical tool may have an internal cooling channel through which a cooling medium is guided and discharged to the main cutting surface and secondary cutting surface of the tool via an outlet port facing the tool tip.

[0201] In the alternative configuration, the mechanical tool has a coaxial central hole that fluidly connects the top of the tool to the tip of the tool. Due to the long working length, a liquid jet guide laser can be guided through the central hole of the mechanical tool. In the first step, the liquid jet guide laser is irradiated to remove the substrate material and form an initial core hole. For this purpose, the portion of the liquid jet laser that extends beyond the tip of the tool is applied. In the finishing step, the laser beam is turned off and the mechanical tool can start rotating at the desired speed to remove any remaining material in the core hole. The liquid jet continues to flow through the mechanical tool toward the workpiece and can act as a coolant on both the mechanical tool and the workpiece substrate.

[0202] Figures 28A to 28D show configurations for cooling a rotary tool according to several embodiments. Figure 28A shows an immersion nozzle 2871 that immerses a workpiece, such as a substrate 2800, with a cold liquid such as water, a coolant, or a lubricant. The cold water flow 2871 can remove the heat generated by friction between the rotary tool and the substrate. During the machining process by the rotary tool 2820, the tool 2820 and the substrate 2800 can be cooled by a liquid cooling flow such as the immersion nozzle 2871. The water may have a temperature below the ambient temperature, for example, below 20°C, below 15°C, or below 10°C.

[0203] Figure 28B shows a configuration in which a gaseous cooling process, such as an air nozzle 2872 directed towards a rotating tool or an area of ​​the substrate being machined, can be used.

[0204] Figure 28C shows a configuration in which a liquid or gaseous cooling process can be used for the channel rotary tool. Liquid 2871A can be supplied to the conduit inside the rotary tool and then flowed outwards toward the substrate or the side wall of the hole.

[0205] Figure 28D shows a configuration using a liquid jet from a liquid jet guided laser head to cool a rotary tool having a hollow tool head. Liquid jet from liquid jet guided laser head 2871 * For example, a liquid flow without internally reflected laser beams can be used to run through the inside of a hollow rotary tool for cooling during the smoothing process.

[0206] Figures 29A-29C show flowcharts for cooling a mechanical rotary tool according to several embodiments. In Figure 29A, operation 2900 smooths the holes in the substrate by rotating the mechanical rotary tool. The mechanical rotary tool is exposed to a liquid or gas flow for cooling. Alternatively, a liquid flow is provided for cooling through a conduit of the mechanical rotary tool. Alternatively, the substrate is submerged in a liquid bath for cooling the mechanical rotary tool.

[0207] In Figure 29B, in operation 2920, a liquid or gas flow is passed through the outer surface or internal conduit of the mechanical rotary tool to cool the mechanical rotary tool while the holes in the substrate are being smoothed.

[0208] In Figure 29C, in operation 2940, a mechanical rotary tool is positioned beneath the liquid jet guided laser head, and the liquid column from the liquid jet guided laser head is configured to pass through an internal conduit in the mechanical rotary tool during the process of smoothing the holes in the substrate.

[0209] In some embodiments, a positioning module, such as a camera, can be used to align a mechanical rotary tool with an initial hole formed by a liquid jet. The positioning module can also be used to align the mechanical rotary tool after the substrate has been inverted, ensuring that the top and bottom processes are properly aligned.

[0210] To precisely finish a core hole to its final diameter, the central axis of the mechanical tool and the central axis of the core hole must be perfectly aligned with each other. An alignment camera can be used to locate the central axis of the core hole. The alignment camera can be mounted on a mounting plate to which the tool spindle is attached. The offset distance between the central axes of the alignment camera and the tool spindle can be known. The alignment camera may have at least one optical element, such as a lens, and at least one spatial detector, such as a camera.

[0211] In the first step, to finish the initial hole formed in the previous liquid jet process, a alignment camera can measure the position of the central axis of the core hole. In the second step, the mounting plate to which the alignment camera and tool spindle are attached is movable by a distance equal to the offset distance between the alignment camera, the tool spindle, and the central axis of the mechanical tool. Once the axis of the mechanical tool is precisely positioned above the central axis of the core hole, the tool spindle can be lowered to begin finishing the core hole to its final diameter. The mechanical tool can perform an up-and-down oscillating motion. Alternatively, the mechanical tool can move in only one direction, from the first surface of the substrate along the core hole, through the second opposite surface of the substrate.

[0212] Using the alignment module, for example, the rotary tool can be aligned to the opening on the opposite side of the initial hole after the substrate has been inverted. For example, after smoothing the first portion from the first opening side of the initial hole, the substrate can be inverted 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 to which the alignment camera and tool spindle are attached can move the offset distance between the alignment camera and the central axis of the tool spindle and mechanical tool. Once the axis of the mechanical tool is precisely positioned above the central axis of the core hole, the tool spindle can be lowered to begin finishing the core hole to its final diameter.

[0213] Figures 30A to 30B show configurations of the alignment module according to several embodiments. In Figure 30A, the rotary tool 3020 and the alignment module 3074 can be mounted on the mounting plate 3077. The distance 3078 between the alignment module and the rotary tool can be determined and used for aligning the rotary tool.

[0214] Figures 30B(a) to 30B(b) show the process of aligning a rotary tool to an initial hole 3001 in the substrate 3000. An alignment module can be used to find the center line of the initial hole. The mounting plate, including the alignment module and the rotary tool, can then be moved a distance equal to the separation distance 3078 between the alignment module and the rotary tool. The rotary tool can then be aligned to the initial hole and then lowered to smooth the initial hole.

[0215] Figures 31A to 31B show different configurations of the alignment module according to several embodiments. In Figure 31A, the rotary tool 3120 and the alignment module 3174 * Mounting plate 3177 * The alignment module can be mounted on the rotary tool, and is mounted in the opposite direction to the rotary tool, for example, the substrate is configured to be positioned between the alignment module and the rotary tool. The alignment module can align with the rotary tool, for example, the alignment module can align with the centerline of the rotary tool.

[0216] Figure 31B shows the process of aligning the rotary tool to the initial hole 3101 in the substrate 3100. The center line of the initial hole can be found using the alignment module. Since the rotary tool is already aligned to the center line of the initial hole, it can then be lowered to smooth the initial hole.

[0217] Figures 32A-32B show flowcharts for aligning a mechanical rotary tool according to several embodiments. In Figure 32A, operation 3200 involves coupling an alignment module to the mechanical rotary tool, which is configured to locate the position of a hole in the substrate from either the top or bottom surface. The distance between the alignment module and the mechanical rotary tool aligns the mechanical rotary tool with respect to the hole. The distance can be zero if the alignment module is positioned opposite the rotary tool.

[0218] In Figure 32B, operation 3220 determines the position of the hole on the substrate using an alignment module coupled to a mechanical rotary tool. Operation 3230 optionally moves the mechanical rotary tool to align with the hole by a predetermined distance between the alignment module and the mechanical rotary tool. This operation is optional if the alignment module is coupled in the opposite direction to the rotary tool, for example, the alignment module is configured to locate the hole from the bottom surface of the substrate. Operation 3240 smooths the hole using the mechanical rotary tool. Operation 3250 repeats the above steps to align and smooth other holes on the substrate.

[0219] In some embodiments, an inspection module, such as 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 of the next initial hole. For example, if the inspected hole passes the quality inspection, such as when the sidewall surface roughness is satisfactory and there is no deterioration damage at the entrance and exit edges of the hole, the rotary tool can move to the next initial hole and continue processing. Alternatively, if the inspected hole fails the quality test, such as when the sidewall surface roughness is unsatisfactory and the entrance or exit edge of the hole shows deterioration damage, the process can be terminated.

[0220] In some embodiments, the dimensions and quality of finished holes in the substrate can be measured. Precision components such as gas distribution plates and uniformity plates for semiconductor processing equipment typically require machining hundreds or thousands of tiny precision holes in a thick ceramic substrate. To ensure stable and repeatable gas distribution, both the entrance and exit of each hole must have sharp, undamaged edges around the circumference. Machines for drilling such holes may have a core-drilling step using an inkjet-guided laser or electrical discharge machining process. The core holes can be finished to the desired final hole diameter and quality with mechanical tools. During the core-drilling or hole-finishing process, holes may be damaged, for example, by being scraped away at the entrance or exit. This can occur due to impurities in the substrate material or, for example, wear of the mechanical tools used to finish the core holes to the desired diameter. To avoid further processing of substrates with one or more defective holes, inspection of each hole can be applied after the mechanical tooling step.

[0221] In some embodiments, the hole inspection process can also be applied after the core hole has been created by a liquid jet guided laser or electrical discharge machining process. A tool spindle with a mechanical tool can be mounted on a mounting plate inside the machine that processes the substrate. An inspection camera can be mounted on the same mounting plate. The inspection camera may include an illumination module for illuminating the substrate surface. The inspection camera may include at least one optical element suitable for projecting an area equal to or wider than the hole diameter onto a sensing device such as a CCD camera. The illumination module can illuminate an area equal to or wider than the hole diameter. Defects around the circumference of the hole can be detected by differences in shape and brightness compared to the desired hole contour.

[0222] In some embodiments, the upper and lower inspection modules can be configured to simultaneously measure the dimensions and quality of the finished holes on both sides of the substrate. The optical axes of the upper and lower inspection modules may be the same; for example, the upper and lower inspection modules each have one identical optical axis. The upper inspection camera may include an upper illumination module that illuminates the top surface of the substrate and illuminates the holes towards the lower inspection camera. The lower inspection camera may include a lower illumination module that illuminates the opposite, underside of the substrate and illuminates the holes towards the upper inspection camera.

[0223] In some embodiments, the upper illumination module can illuminate the entrance to the hole. The upper inspection camera can detect defects in the circumference of the hole by analyzing the differences in shape and brightness compared to a desired hole contour. Such analysis can be performed by connecting the upper inspection camera to, for example, a computing device. In addition to turning on the upper illumination module, turning on the lower illumination module allows the upper inspection camera to detect defects inside the hole itself, such as non-circularity, high roughness, or particles in the side walls of the hole. The upper and lower illumination modules can be turned on simultaneously or sequentially.

[0224] In some embodiments, the bottom illumination module can illuminate the hole exit. The bottom inspection camera can detect defects around the hole by analyzing the differences in shape and brightness compared to a desired hole contour. Such analysis can be performed by connecting the top inspection camera to, for example, a computing device. In addition to turning on the bottom illumination module, turning on the top illumination module allows the bottom inspection camera to detect defects inside the hole itself, such as non-circularity, high roughness, or particles on the side walls of the hole.

[0225] Figures 33A - 33B show the configuration of an inspection module according to some embodiments. In Figure 33A, a rotary tool 3320 and an inspection module 3375 can be attached to a mounting plate. The distance between the inspection module and the rotary tool is determined and can be used for aligning the inspection module after the rotary tool has completed processing. The inspection module can include a light source 3375A, such as an LED light. The inspection module can include an inspection camera 3375B for imaging the machined hole. The inspection module can include a processing module 3375C for analyzing the image captured by the camera 3375B.

[0226] During operation, the rotary tool 3320 can finish the initial hole by, for example, smoothing the sidewalls and opening an initial hole with the final desired diameter. The mounting module to which the inspection module and the rotary tool are attached can move a distance equal to the separation between the inspection module and the rotary tool. The inspection module can then inspect the quality of the hole just machined by the rotary tool.

[0227] In Figure 33B, an upper inspection module 3375 and a lower inspection module 3375 * can be coupled to the rotary tool 3320. The upper and bottom inspection modules can be aligned, for example, to have the same optical axis for inspecting the upper and bottom of the hole.

[0228] Figures 34A - 34B show a flowchart for inspecting the final holes of a substrate according to some embodiments. In Figure 34A, in operation 3400, an inspection module is coupled to a mechanical rotary tool, and the inspection module is configured to inspect the characteristics of the holes in the substrate from the top or bottom surface. The distance between the inspection module and the mechanical rotary tool is used to align the inspection module with respect to the hole after it has been smoothed by the rotary tool.

[0229] In FIG. 34B, in operation 3420, a mechanical rotary tool is used to smooth the holes in the substrate while the rotary tool is coupled to the inspection module. In operation 3430, the mechanical rotary tool is moved to align the inspection module with the hole based on a predetermined distance between the inspection module and the mechanical rotary tool. In operation 3440, the inspection module is used to inspect the hole. In operation 3450, the previous steps are repeated to smooth and inspect other holes in the substrate.

[0230] In some embodiments, the present invention discloses a method and system for forming holes in a substrate that can be used for a gas distribution plate and a uniform plate. The method can include forming initial holes in the substrate using a liquid jet guided laser system, or an electrical discharge machining system, or a combination of a liquid jet guided laser system and an electrical discharge machining system. The method can further include finishing the formed initial holes, such as enlarging the initial holes to a desired final diameter while ensuring that the sidewalls of the final holes are smooth and the edges of the inlet and outlet are not damaged. The finishing process can be performed by a mechanical rotary tool such as a drill bit, a reamer, a milling bit, a boring bar, or a honing bit.

[0231] In some embodiments, the hole formation process and the hole finishing process can be performed by different devices, such as a first device of a liquid jet guided laser system for forming initial holes and a second device of a mechanical rotary tool for finishing the initial holes.

[0232] FIG. 35 shows a flowchart for completely forming holes in a substrate according to some embodiments. The complete hole formation can include forming initial holes in the substrate and finishing the initial holes with a mechanical tool to a desired hole diameter having desired characteristics.

[0233] In operation 3500, at least one hole is machined into the substrate, in which case 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. In operation 3510, the desired hole diameter is determined, in which case the desired hole diameter is less than 2 mm. In operation 3520, the core hole is drilled, in which case a liquid jet guided laser or electrical discharge machining process is applied to make the core hole diameter equal to or smaller than the desired final hole diameter. In operation 3530, the precise position of the core hole is determined, in which case a camera is applied to measure the position of the hole as an offset distance relative to the spindle. In operation 3540, a mechanical tool is provided to the spindle, in which case the mechanical tool is one of a drill bit, reamer, or milling tool, and at least the end of the cutting surface of the tool is made of one of carbide or synthetic diamond material. In operation 3550, the core hole is finished to the desired diameter, in which case a mechanical tool is applied to remove any remaining material between the core hole diameter and the desired diameter. The substrate may include metal substrates and other workpieces having holes.

[0234] In some embodiments, the present invention discloses the integration of a liquid jet and a mechanical rotary cutting tool for forming holes in a substrate. 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 within 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 edges of the hole entrance and exit.

[0235] The mechanical tool has a coaxial central hole that fluidly connects the tool's upper part and its tip. Due to its long working length, a liquid jet guide laser can be guided through the central hole of the mechanical tool.

[0236] Figure 36 shows the configuration of an integrated system of a liquid jet and a mechanical rotary tool according to several embodiments. The integrated system 3626, for example, a combination of a liquid jet guided laser head 3610 and a mechanical 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 that holds a window 3612. Below the window 3612 is a liquid jet nozzle 3615. A liquid source, such as a water source 3614, can be pressed into the space between the window 3612 and the nozzle 3615 to form a laminar flow liquid jet 3616A. To process the material, a laser beam from a laser power source 3611 is focused and guided from the window 3612 through the orifice of the liquid jet nozzle 3615 into the laminar flow 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 within the liquid jet.

[0237] 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 an internal conduit in the air jet module 3627. A high-capacity flow from the compressed gas source 3617 is provided through an external and mechanically spaced conduit outside the air jet module 3627, but the conduit runs parallel to the liquid jet guided laser 3616 and toward the surface of the substrate 3600. The compressed gas flow 3618 acts as a coaxial, spaced shield to avoid interference induced by the reverse jet of the liquid jet guided laser 3616.

[0238] The mechanical hollow rotary tool head 3620 may include a mechanical hollow rotary tool, which may have conduits through which the rotary tool passes. The mechanical hollow rotary tool head 3620 can be configured, for example, so that a liquid jet from a liquid jet guide laser head enters the conduit to cool the mechanical hollow rotary tool.

[0239] By integrating the operating mechanism into an integrated system, the liquid jet guide laser head and the mechanical rotary tool can be moved, for example, in a plane perpendicular to the liquid jet, or in three-dimensional movement parallel and perpendicular to the liquid jet.

[0240] The liquid jet guided laser beam 3616 can be configured to create a hole in a substrate having an initial diameter of 3606, for example, by cutting cylindrical material by traveling multiple passes along a circular contour using a linear cutting process, or by rastering multiple passes inside a closed-loop contour to form a hole inside the closed-loop contour.

[0241] The mechanical rotary tool can be configured to perform finishing tasks such as enlarging the initial hole to a final diameter of 3602 mm and smoothing the side walls of the final hole.

Claims

1. It is a method, Using a liquid jet guided laser beam to form holes in a substrate, The method includes smoothing the hole using a mechanical rotary tool to obtain the final dimensions, The liquid jet guided laser beam includes a laser beam that has been internally reflected within the liquid column. The liquid column is formed by flowing the liquid through a nozzle. The internally reflected laser beam is formed by focusing the laser beam within the liquid column. The aforementioned mechanical rotary tool is operated by a mechanical rotary system. The mechanical rotary tool includes a diameter suitable for the final dimensions of the hole, method.

2. The method according to claim 1, A method wherein the holes are configured to provide a fluid connection between the upper and lower surfaces of the substrate.

3. The method according to claim 1, The formation of the hole using the liquid jet guided laser beam includes forming the hole using at least one of circular motion or helical motion, A method wherein the circular motion or the helical motion is configured to form a hole having a diameter between 75 and 99% of the final dimension.

4. The method according to claim 1, A method for forming the hole using the liquid jet guided laser beam, wherein the hole has a diameter 0.05 mm smaller than the final dimension.

5. The method according to claim 1, A method wherein the diameter of the hole formed by the liquid jet guided laser system is configured to minimize the total processing time between the liquid jet guided laser beam and the mechanical rotary tool.

6. The method according to claim 1, A method wherein the mechanical rotary tool is configured to smooth the hole to achieve a surface finish having a mean roughness (Ra) of less than 0.3 micrometers.

7. The method according to claim 1, A method wherein the liquid jet guide laser beam and the mechanical rotary tool are configured to form and smooth the hole having a sharp edge that is undamaged around its circumference.

8. The method according to claim 1, A method wherein the substrate comprises at least one of silicon, silicon carbide, aluminum nitride, silicon nitride, titanium nitride, boron carbide, ceramic matrix composite material (CMC), or metal matrix composite material (MMC).

9. The method according to claim 1, The method further includes forming a coaxial gas flow surrounding the liquid column, A method wherein the coaxial gas flow is configured to minimize interference to the liquid column due to reverse jetting of the liquid column when it collides with the substrate.

10. The method according to claim 1, A method wherein the formation of the hole using the liquid jet guided laser beam and the finishing of the hole using the mechanical rotary tool are performed on the same machine.

11. The method according to claim 1, A method in which the formation of the hole using the liquid jet guided laser beam and the finishing of the hole using the mechanical rotary tool are performed by separate machines.

12. The method according to claim 1, A method wherein the mechanical rotary tool includes a mechanical drill bit, a mechanical reamer, a mechanical boring bar, a mechanical milling tool, or a mechanical honing tool.

13. The method according to claim 1, A method wherein the mechanical rotating tool includes an end made of polycrystalline diamond or single-crystal diamond material.

14. The method according to claim 1, The hole is configured to completely penetrate the substrate, The method further comprises detecting the opening of the hole by at least one of an optical sensor or an acoustic sensor.

15. The method according to claim 1, The method further includes heating the substrate during the formation of the hole using the liquid jet guide laser beam, Heating the substrate includes at least one of the following: flowing a liquid at a temperature higher than the ambient temperature over the surface of the substrate; flowing a gas at a temperature higher than the ambient temperature over the surface of the substrate; applying infrared radiation or inductive energy to the surface of the substrate; or immersing the substrate in a liquid at a temperature higher than the ambient temperature. A method wherein the temperature of a liquid or gas that is higher than the ambient temperature is between 50 and 100 degrees Celsius.

16. The method according to claim 1, The method further includes inspecting the hole after smoothing it with the aforementioned mechanical rotary tool, The method of the aforementioned examination, including the use of a camera.

17. A substrate having a first surface facing the liquid jet guide laser head is arranged, The liquid jet guided laser beam generated from the liquid jet guided laser head is used to form multiple blind holes in the substrate, The substrate is inverted so that the second surface of the substrate faces the liquid jet guide laser head, Aligning each of the aforementioned blind holes with the liquid jet guide laser beam, Through holes penetrating each of the aforementioned blind holes are formed by a liquid jet guide laser beam, Smoothing the through hole using a mechanical rotary tool and A method including, The liquid jet guided laser beam includes a laser beam that has been internally reflected within the liquid column. The liquid column is formed by flowing the liquid through the nozzle. The second surface is on the opposite side of the first surface. method.

18. The method according to claim 17, A method comprising detecting the liquid jet guide laser beam forming the through hole by at least one of an optical sensor or an acoustic sensor.

19. The method according to claim 17, The method further includes inspecting the hole after smoothing it with the aforementioned mechanical rotary tool, The method of the aforementioned examination, including the use of a camera.

20. It is a method, Using a liquid jet guided laser beam to form holes in a substrate, The method includes smoothing the hole using a mechanical rotary tool, The liquid jet guided laser beam includes a laser beam that has been internally reflected within the liquid column. The liquid column is formed by flowing the liquid through the nozzle. The aforementioned mechanical rotary tool includes an end made of synthetic diamond material, method.

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