Through glass via (TGV) forming apparatus, and inspection method therefor

Abstract

Disclosed is a through glass via (TGV) forming apparatus comprising: a first light source for generating a first laser beam; a second light source for generating a second laser beam having a repetition rate lower than that of the first laser beam; a polarization converter for converting the polarization state of the second laser beam into radial polarization; a plurality of axicon lenses for converting, into a Bessel beam, the second laser beam having the converted polarization state; and a control module for controlling the first light source and the second light source, wherein the control module controls the emission time points of the first laser beam and the second laser beam such that plasma is generated by emitting the first laser beam at the glass substrate, and then a through-hole is formed by emitting the Bessel beam.

Description

TGV (THROUGH GLASS VIA) forming device and inspection method thereof

[0001] The present disclosure relates to a Through Glass Via (TGV) forming apparatus and a method for inspecting the same, and more specifically, to an apparatus and method capable of forming a TGV and inspecting its quality in real time.

[0002] In advanced electronics industries such as semiconductor packaging, displays, and MEMS (Micro-Electro-Mechanical Systems), the technology of forming micro through-holes in glass substrates is utilized with great importance. In particular, Through Glass Via (TGV) technology has established itself as a core technology essential for various applications, such as 3D stacked semiconductors and high-density circuit connections, by forming holes that penetrate a glass substrate and filling them with conductive materials to enable electrical connections.

[0003] Conventional methods for forming TGVs have mainly involved mechanical drilling, chemical etching, and laser processing. However, mechanical drilling has limitations in micro-processing of 10 μm or less and carries a high risk of substrate damage during processing, while chemical etching has the disadvantages of a complex process and causing environmental problems. Due to these limitations, laser processing has recently become widely used, but conventional laser processing using a Gaussian beam inevitably results in a taper phenomenon due to the characteristics of the beam energy distribution, making it difficult to form vertical through-holes.

[0004] The taper phenomenon is a phenomenon in which energy decreases as a laser beam propagates in the depth direction, forming a hole that is wider at the top and narrower at the bottom; this acts as a serious constraint in advanced electronic components requiring high-density wiring. In addition, due to the limited depth of focus of the Gaussian beam, it is difficult to penetrate thick glass substrates in a single process, often requiring multi-stage processing, which leads to increased processing time and costs.

[0005] Furthermore, existing TGV forming devices adopt a method of verifying quality through a separate inspection process after processing, which has the limitation that defects can only be detected after a significant amount of time and resources have already been consumed. Due to the lack of capabilities to monitor the TGV forming status in real time and immediately detect defects, there is significant room for improvement in terms of production efficiency and yield.

[0006] The purpose of the embodiment disclosed in this disclosure is to provide a TGV forming device that processes a hole using two laser beams, one for bursting and one for processing, and inspects the processing state.

[0007] The problems that this disclosure aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description below.

[0008] An apparatus according to the present disclosure for solving the above-mentioned technical problem comprises: a first light source for generating a first laser beam; a second light source for generating a second laser beam having a repetition rate lower than that of the first laser beam; a polarization converter for converting the polarization state of the second laser beam into a radial one; a plurality of axicon lenses for converting the second laser beam with the converted polarization state into a Bessel beam; and a control module for controlling the first light source and the second light source, wherein the control module controls the timing of the emission of the first laser beam and the second laser beam such that the first laser beam is irradiated onto a glass substrate to generate plasma, and then the Bessel beam is irradiated to form a through hole.

[0009] Meanwhile, the apparatus further includes an AC power source that applies voltage to an IDT (interdigital transducer) element formed on the glass substrate, and the control module can monitor changes in voltage measured by the IDT element to inspect the condition of a through hole formed on the glass substrate.

[0010] In addition, the control module may determine that the through hole is formed normally when the voltage measured by the IDT element decreases below a threshold voltage.

[0011] In addition, the control module can control the focal position formed by the Bessel beam by adjusting the distance between the plurality of axicon lenses.

[0012] In addition, the plurality of axicon lenses can generate the Bessel beam having a plurality of focal positions and provide the Bessel beam to a plurality of depth-direction focal positions of the glass substrate.

[0013] Additionally, it may further include a polarization beam splitter into which the first laser beam and the second laser beam, having mutually orthogonal polarization states, are incident, and which emits the first laser beam and the second laser beam along the same path to provide them to the polarization converter.

[0014] Meanwhile, the method according to the present disclosure is a method for inspecting the processing state of a through hole by a TGV (Through Glass Via) forming device, comprising: a step of applying voltage to a first IDT (interdigital transducer) element formed on a glass substrate; a step of measuring voltage at a second IDT element formed between the first IDT element and the through hole; and a step of inspecting the processing state of the through hole according to whether the measured voltage decreases.

[0015] Meanwhile, the method may further include the step of generating plasma by irradiating a first laser beam onto the glass substrate; and the step of forming the through hole by irradiating a second laser beam having a lower repetition rate than the first laser beam onto the glass substrate.

[0016] Additionally, the step of forming the through hole may include: generating a second laser beam having a repetition rate lower than that of the first laser beam; converting the polarization state of the second laser beam to a radial state; converting the second laser beam with the converted polarization state into a Bessel beam; and irradiating the glass substrate with the Bessel beam to form the through hole.

[0017] Additionally, the step of inspecting the processing state of the through hole may include a step of determining the processing state of the through hole as normal when the measured voltage decreases to below a threshold voltage.

[0018] According to the aforementioned means for solving the problem of the present disclosure, by forming plasma before processing, the effect of improving processing precision is achieved through increasing the energy efficiency of the processing laser. In addition, unlike a general Gaussian beam, a Bessel beam having a radial polarization state maintains a long focal point, which can minimize the occurrence of taper during hole processing.

[0019] In addition, by presenting a method that generates a Surface Acoustic Wave (SAW) to inspect quality immediately upon TGV formation, it has the advantageous effect of detecting defects early and optimizing the process in real time.

[0020] The effects of the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description below.

[0021] FIG. 1 is a drawing showing a TGV forming device according to one embodiment of the present disclosure.

[0022] Figure 2 is a diagram illustrating the change in the polarization state of a laser beam by the polarization converter shown in Figure 1.

[0023] FIG. 3 is a diagram illustrating a Bessel beam forming method using a plurality of axicon lenses shown in FIG. 1.

[0024] FIG. 4 is a diagram illustrating a method for forming a TGV by the device shown in FIG. 1.

[0025] FIG. 5 is a drawing showing a TGV forming device according to another embodiment of the present disclosure.

[0026] Figures 6 and 7 are drawings showing an example of an IDT element formed on a glass substrate.

[0027] Figures 8 and 9 are diagrams illustrating the change in voltage measured in an IDT element according to the processing state of the through hole.

[0028] FIG. 10 is a flowchart of a TGV processing state inspection method according to one embodiment of the present disclosure.

[0029] Throughout this disclosure, the same reference numerals denote the same components. This disclosure does not describe all elements of the embodiments, and general content in the art to which this disclosure pertains or content that overlaps between embodiments is omitted. The terms 'part, module, component, block' as used in the specification may be implemented in software or hardware, and depending on the embodiments, a plurality of 'parts, modules, components, blocks' may be implemented as a single component, or a single 'part, module, component, block' may include a plurality of components.

[0030] Throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are directly connected but also cases where they are indirectly connected, and indirect connections include connections made via a wireless communication network.

[0031] Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0032] Throughout the specification, when it is stated that a component is located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components.

[0033] The terms first, second, etc. are used to distinguish one component from another, and the components are not limited by the aforementioned terms.

[0034] Singular expressions include plural expressions unless there is an obvious exception in the context.

[0035] In each step, identification codes are used for convenience of explanation and do not describe the order of the steps; the steps may be performed differently from the specified order unless a specific order is clearly indicated in the context.

[0036] The operating principles and embodiments of the present disclosure will be described below with reference to the attached drawings.

[0037] In this specification, the term "device according to the present disclosure" includes all various devices capable of performing computational processing and providing results to a user. For example, the device according to the present disclosure may include all of a computer, a server device, and a portable terminal, or may be in the form of any one of these.

[0038] Here, the computer may include, for example, a notebook, desktop, laptop, tablet PC, slate PC, etc. equipped with a web browser.

[0039] The above server device is a server that processes information by communicating with an external device, and may include an application server, a computing server, a database server, a file server, a game server, a mail server, a proxy server, and a web server.

[0040] The above portable terminal may include, for example, all types of handheld-based wireless communication devices such as PCS (Personal Communication System), GSM (Global System for Mobile communications), PDC (Personal Digital Cellular), PHS (Personal Handyphone System), PDA (Personal Digital Assistant), IMT (International Mobile Telecommunication)-2000, CDMA (Code Division Multiple Access)-2000, W-CDMA (W-Code Division Multiple Access), WiBro (Wireless Broadband Internet) terminals, smartphones, etc., as well as wearable devices such as watches, rings, bracelets, anklets, necklaces, glasses, contact lenses, or head-mounted devices (HMDs).

[0041] Functions related to artificial intelligence according to the present disclosure are operated through a processor and memory. The processor may be composed of one or more processors. In this case, the one or more processors may be general-purpose processors such as CPUs, APs, and DSPs (Digital Signal Processors), graphics-dedicated processors such as GPUs and VPUs (Vision Processing Units), or artificial intelligence-dedicated processors such as NPUs. The one or more processors control the processing of input data according to predefined operation rules or artificial intelligence models stored in memory. Alternatively, if the one or more processors are artificial intelligence-dedicated processors, the artificial intelligence-dedicated processors may be designed with a hardware structure specialized for processing a specific artificial intelligence model.

[0042] FIG. 1 is a drawing showing a TGV forming device according to one embodiment of the present disclosure.

[0043] Referring to FIG. 1, a TGV forming device (1) according to one embodiment of the present disclosure includes a first light source (10), a second light source (20), a polarizing beam splitter (30), a polarizing converter (40), a plurality of axicon lenses (50) and a control module (70), and can form a TGV by processing a through hole in a glass substrate (G).

[0044] The first light source (10) can generate a first laser beam.

[0045] In this embodiment, the first laser beam has a repetition rate in the GHz band, and, for example, can be generated with a wavelength of 1 µm and a pulse width of 1 ps or more.

[0046] The second light source (20) has a lower repetition rate than the first laser beam and can generate a second laser beam having a higher pulse energy (uJ) than the first laser beam.

[0047] In this embodiment, the second laser beam has a repetition rate in the MHz band, and, for example, can be generated with a wavelength of 0.5 µm and a pulse width of 0.5 ps or less.

[0048] The polarizing beam splitter (30) can receive the first laser beam and the second laser beam and emit the first laser beam and the second laser beam along the same path.

[0049] In this embodiment, the first laser beam and the second laser beam may have polarization states that are orthogonal to each other. For example, the first laser beam may have a horizontal polarization state, and the second laser beam may have a vertical polarization state.

[0050] The polarization beam splitter (30) transmits the first laser beam and reflects the second laser beam, so that at the output end, the polarization states of the first laser beam and the second laser beam form a cross shape and are emitted along the same path.

[0051] The polarization converter (40) can receive a first laser beam and a second laser beam from the polarization beam splitter (30) and can convert the polarization state of the second laser beam into a radial one.

[0052] As described above, the second laser beam has a linear polarization state in the vertical direction and can be provided to a polarization converter (40), and the polarization converter (40) can convert the polarization state of the second laser beam into a radial polarization state. A detailed explanation regarding this will be provided later with reference to FIG. 2.

[0053] A plurality of axicon lenses (50) can convert a second laser beam with a converted polarization state into a Bessel beam. A detailed explanation regarding this will be provided later with reference to FIG. 3.

[0054] The Bessel beam has the highest energy density along the optical axis and is distributed in multiple concentric circles around the optical axis; unlike a typical Gaussian beam, it possesses a long depth of focus (DOF) that maintains the focus for an extended period. Meanwhile, in this embodiment, by forming the Bessel beam from a second laser beam having a radial polarization state, the region where energy is focused around the optical axis will be maintained for a longer duration.

[0055] The control module (70) can control the first light source (10), the second light source (20), the polarization beam splitter (30), the polarization converter (40), and the plurality of axicon lenses (50) to perform a process for forming a through hole (TGV) in a glass substrate (G).

[0056] In this embodiment, the first laser beam is used for bursting to form plasma on the glass substrate (G), and the Bessel beam converted from the second laser beam can be used for processing to form a through hole (TGV) on the glass substrate (G). At this time, the first laser beam forms plasma on the glass substrate (G) before processing, thereby enhancing the processing precision through increased energy efficiency of the processing laser. In addition, unlike a general Gaussian beam, the Bessel beam, which has a radial polarization state, maintains a long focal length, which can minimize the occurrence of taper when processing holes in the glass substrate (G). Meanwhile, the angle of taper formation can be arbitrarily set by adjusting the energy focusing intensity by adjusting the repetition rate of the first laser beam.

[0057] The control module (70) can control the timing of the emission of the first laser beam and the second laser beam from the first light source (10) and the second light source (20) so that the first laser beam first reaches the glass substrate (G) to generate plasma, and then the Bessel beam reaches it to process the through hole (TGV).

[0058] For example, the control module (70) can control the irradiation of a first laser beam from a first light source (10) and then control the irradiation of a second laser beam from a second light source (20) after a preset delay time. Here, the delay time is the time during which plasma is sufficiently generated on the glass substrate (G) and its surface characteristics are optimized, and can be adjusted according to the thickness or type of the glass substrate (G).

[0059] Additionally, the control module (70) may control the distance between multiple axicon lenses (50) to adjust the focal position of the Bessel beam.

[0060] Meanwhile, a TGV forming device (1) according to one embodiment of the present disclosure may further include a first mirror (35) and a second mirror (55).

[0061] The first mirror (35) can be positioned between the second light source (20) and the polarization beam splitter (30) and can reflect the second laser beam emitted from the second light source (20) so that it is incident on the polarization beam splitter (30).

[0062] For example, the first mirror (35) may be mounted on a precision mount and configured to allow for angle adjustment, and the angle may be adjusted so that the second laser beam is incident on the center of the polarization beam splitter (30).

[0063] The second mirror (55) can reflect the first laser beam and the Bessel beam so that they are incident perpendicularly on the glass substrate (G).

[0064] For example, the second mirror (55) can be mounted on a precision mount and configured to allow for angle adjustment, and can reflect the first laser beam and the Bessel beam so that they are incident in the depth direction of the glass substrate (G).

[0065] Figure 2 is a diagram illustrating the change in the polarization state of a laser beam by the polarization converter shown in Figure 1.

[0066] Referring to FIG. 2, the polarization converter (40) can convert a linear polarization state as in FIG. 2 (a) into a radial polarization state as in FIG. 2 (b).

[0067] For example, the polarization converter (40) may be provided as a liquid crystal-based spatial light modulator and may be placed at the output terminal of the polarization beam splitter (30) to receive the first laser beam and the second laser beam. The polarization converter (40) may not convert the polarization state of the first laser beam, but may radially convert only the polarization state of the second laser beam. For example, the polarization converter (40) may be designed to operate only for a specific wavelength by utilizing the wavelength difference between the first laser beam and the second laser beam.

[0068] The polarization converter (40) can convert the polarization state of a linear second laser beam into a radial polarization state and provide it to a plurality of axicon lenses (50). According to the present disclosure, by generating a Bessel beam from a second laser beam having such a radial polarization state, a longer section in which energy is focused around the optical axis of the Bessel beam can be formed.

[0069] FIG. 3 is a diagram illustrating a Bessel beam forming method using a plurality of axicon lenses shown in FIG. 1.

[0070] Referring to FIG. 3, a plurality of axicon lenses (50) include a first axicon lens (51) and a second axicon lens (52) to obtain a Bessel beam (L2) from a second laser beam (L2). B ) can be generated and irradiated onto a glass substrate (G). Meanwhile, in FIG. 3, the apparatus (1) according to the present disclosure is illustrated as having two axicon lenses (51, 52), but is not limited thereto and can have two or more axicon lenses.

[0071] The first axicon lens (51) and the second axicon lens (52) are cone-shaped lenses having a preset base angle, and the second laser beam (L2) having a radial polarization state is a Bessel beam (L B It can be converted into ).

[0072] For example, the first axicon lens (51) spreads the incident second laser beam (L2) linearly, and the second axicon lens (52) aligns the linearly spread second laser beam (L2) in parallel to form a Bessel beam (L B It can be converted into ).

[0073] Meanwhile, the device (1) according to the present disclosure may further include a focusing lens (55) disposed at the output end of a plurality of axicon lenses (51, 52).

[0074] The focusing lens (55) can be provided as an objective lens, etc., and the Bessel beam (L B) is directed to a preset processing spot on the glass substrate (G).

[0075] Meanwhile, as shown in FIG. 3, a Bessel beam (L B ) forms a focal region where energy is focused around the optical axis, and as it has a radial polarization state, that focal region will be formed longer compared to the case where it has a linear polarization state.

[0076] In addition, as illustrated in FIG. 3, the device (1) according to the present disclosure utilizes at least two axicon lenses to form a Bessel beam (L B By forming ), a longer focal length is formed compared to the case where a single axicon lens is used.

[0077] Meanwhile, the control module (70) controls the distance between the first axicon lens (51) and the second axicon lens (52) to control the Bessel beam (L B The focus range of ) can be adjusted.

[0078] For example, the control module (70) can adjust the distance between the first axicon lens (51) and the second axicon lens (52) in preset units through a precision stage. When the distance between the first axicon lens (51) and the second axicon lens (52) becomes shorter, the focal length of the Bessel beam (LB) will also become shorter, and in the opposite case, the Bessel beam (L B The focal length of ) will also be extended. The control module (70) controls the distance between the first axicon lens (51) and the second axicon lens (52) according to the thickness or material of the glass substrate (G) so that the Bessel beam (L) B The focal range formed by ) and the focal position accordingly can be controlled.

[0079] Meanwhile, in another embodiment, a plurality of axicon lenses (50) have a plurality of Bessel beams (L) having different focal positions. B Generates ) and multiple Bessel beams (L BBy superimposing ) and irradiating the glass substrate (G), processing of multiple depth-direction focal positions of the glass substrate (G) can be performed simultaneously or sequentially.

[0080] Meanwhile, in another embodiment, a plurality of axicon lenses (50) further include a phase control element to form a multi-focal Bessel beam (L) in which a focal section where energy is concentrated is formed at a plurality of points. B Can generate ).

[0081] For example, the phase control element may be provided as an SLM (Spatial Light Modulator), DOE (Diffractive Optical Element), and LCOS (Liquid Crystal on Silicon). In such a case, a plurality of axicon lenses (50) generate a multi-focal Bessel beam (LB) to enable simultaneous processing of multiple depths of the glass substrate (G), and enable adjustment of the shape and irradiation angle through multi-axis beam shaping (optical shaping).

[0082] FIG. 4 is a diagram illustrating a method for forming a TGV by the device shown in FIG. 1.

[0083] Referring to FIG. 4(a), a first laser beam (L1) can be irradiated onto a glass substrate (G) to generate plasma (P). To do this, the first laser beam (L1) will be irradiated onto the glass substrate (G) with a high repetition rate (GHz band) and low pulse energy.

[0084] Referring to FIG. 4(b), after plasma (P) is generated on the glass substrate (G), a Bessel beam (L B ) can be irradiated onto a glass substrate (G) to form a through hole (TGV). At this time, as plasma (P) is generated on the surface of the glass substrate (G), the surface temperature rises and the molecular structure changes, resulting in an increased laser absorption rate; accordingly, the Bessel beam (L BWhen forming through holes (TGV) by ), an improvement in processing quality can be expected.

[0085] Also, Bessel beam (L B Since it is generated from a second laser beam (L2) having a radial polarization state, the energy-focused focal length is formed relatively long, thereby minimizing or preventing tapering when forming a through hole (TGV).

[0086] The control module (70) then irradiates the glass substrate (G) with a first laser beam (L1) to generate sufficient plasma (P), and then the Bessel beam (L B The timing of the irradiation of the first light source (10) and the second light source (20) can be controlled so that ) can be irradiated.

[0087] FIG. 5 is a drawing showing a TGV forming device according to another embodiment of the present disclosure.

[0088] Referring to FIG. 5, a TGV forming device (1') according to another embodiment of the present disclosure may further include an AC power source (90) compared to the device (1) shown in FIG. 1.

[0089] In the following description, only the AC power source (90) is described, and the descriptions of the remaining first light source (10), second light source (20), polarization beam splitter (30), polarization converter (40), multiple axicon lenses (50), and control module (70) are replaced with the descriptions above.

[0090] A TGV forming device (1') according to another embodiment of the present disclosure has a Bessel beam (L) having a radial polarization state as described above. B A through hole (TGV) can be formed using ), and the processing status can be monitored.

[0091] The AC power source (90) can apply voltage to an IDT (interdigital transducer) element formed on a glass substrate (G).

[0092] An IDT device is a metal electrode device that generates surface acoustic waves (SAW), and when an AC power source is applied, a piezoelectric effect occurs, which can generate and propagate surface acoustic waves.

[0093] The control module (70) can monitor changes in voltage measured by the IDT element to inspect the condition of the through hole (TGV) formed in the glass substrate (G). This will be explained with reference to FIG. 6 and below.

[0094] Figures 6 and 7 are drawings showing an example of an IDT element formed on a glass substrate.

[0095] Referring to FIG. 6, the glass substrate (G) may include a piezo thin film layer (5) and an IDT element (3).

[0096] For example, the piezo thin film layer (5) can be formed by depositing a thin film of AIN, ZnO, etc. on the lower part of the glass substrate (G).

[0097] The IDT element (3) is a metal electrode pattern formed on a piezo thin film layer (5), which can be formed through a photolithography process, and, for example, the electrode material can be formed of Au, etc.

[0098] Referring to FIG. 7, multiple IDT elements (3) can be formed with a preset width and spacing.

[0099] For example, the first IDT element (3a) and the second IDT element (3b) may be formed spaced apart at a predetermined interval, and a plurality of through holes (TGV) may be formed between the first IDT element (3a) and the second IDT element (3b).

[0100] The first IDT element (3a) acts as a transmitter that generates SAW by applying voltage from an AC power source (90), and the second IDT element (3b) can act as a receiver that receives SAW.

[0101] The control module (70) controls the AC power supply (90) so that an AC signal is applied to the first IDT element (3a) and can measure the voltage at the second IDT element (3b).

[0102] Figures 8 and 9 are diagrams illustrating the change in voltage measured in an IDT element according to the processing state of the through hole.

[0103] Referring to FIG. 8(a), when the through hole (TGV) is being processed or processed abnormally, it can be confirmed that the SAW flows smoothly from the first IDT element (3a) to the second IDT element (3b). In such a case, since the second IDT element (3b) can be seen to have reached the SAW with almost no attenuation, a relatively high voltage will be measured.

[0104] Referring to FIG. 8(b), when the through hole (TGV) is properly processed, it can be seen that the flow of SAW is obstructed by the through hole (TGV) formed between the first element (3a) and the second element (3b). That is, when the through hole (TGV) is properly formed in the glass substrate (G), a discontinuity surface is formed in the propagation path of the SAW, thereby causing scattering and reflection of the SAW. In such a case, the second IDT element (3b) can be considered to have reached a state where the energy of the SAW has decreased, so a relatively low voltage will be measured.

[0105] Referring to FIG. 9, the control module (70) can measure the real-time voltage at the second IDT element (3b) and monitor the change in the measured voltage to inspect the condition of the through hole (TGV) formed in the glass substrate (G).

[0106] For example, the control module (70) can determine that the through hole (TGV) is being processed, is unprocessed, or is incompletely processed if the voltage measured by the second IDT element (3b) has a decreasing pattern, as in section a of FIG. 9.

[0107] The control module (70) can determine that the through hole (TGV) has been properly formed by completely penetrating the glass substrate (G) when the voltage measured by the second IDT element (3b) decreases below the threshold voltage as in section b of FIG. 9.

[0108] The device (1') according to another embodiment of the present disclosure has the advantageous effect of being able to inspect the quality immediately upon TGV formation, detect defects early, and optimize the process in real time.

[0109] FIG. 10 is a flowchart of a TGV processing state inspection method according to one embodiment of the present disclosure.

[0110] Referring to FIG. 10, a method for inspecting the processing state of a TGV according to one embodiment of the present disclosure can be performed by the device (1') shown in FIG. 5 and may include the steps of creating a through hole (TGV) (S10), applying voltage to an IDT element (3) (S30), monitoring the voltage measured by the IDT element (3) (S50), and inspecting the creation state of the through hole (S70).

[0111] The control module (70) can control the first light source (10) and the second light source (20) to form a through hole (TGV) in the glass substrate (G).

[0112] For example, the control module (70) can generate plasma by controlling the first light source (10) so that a first laser beam is irradiated onto a glass substrate (G).

[0113] Additionally, the control module (70) can form a through hole (TGV) by controlling the second light source (20) so that a second laser beam having a lower repetition rate than the first laser beam is irradiated after sufficient plasma is generated on the glass substrate (G). At this time, the polarization state of the second laser beam is converted to radial by a polarization converter (40), and converted into a Bessel beam by a plurality of axicon lenses (50) and irradiated onto the glass substrate (G).

[0114] The control module (70) can control the AC power supply (90) to apply voltage to the first IDT element (3a).

[0115] The control module (70) can monitor the voltage at the second IDT element (3b) by measuring it.

[0116] The control module (70) can monitor whether the voltage measured by the second IDT element (3b) decreases below a threshold voltage, and if the voltage measured by the second IDT element (3b) decreases below a threshold voltage, it can determine that the processing state of the through hole (TGV) is normal.

[0117] Meanwhile, the disclosed embodiments may be implemented in the form of a recording medium that stores instructions executable by a computer. The instructions may be stored in the form of program code and, when executed by a processor, may generate a program module to perform the operation of the disclosed embodiments. The recording medium may be implemented as a computer-readable recording medium.

[0118] Computer-readable recording media include all types of recording media that store instructions that can be decoded by a computer. Examples include ROM (Read Only Memory), RAM (Random Access Memory), magnetic tape, magnetic disk, flash memory, optical data storage devices, etc.

[0119] As described above, the disclosed embodiments have been explained with reference to the attached drawings. Those skilled in the art will understand that the present disclosure may be practiced in forms different from the disclosed embodiments without changing the technical spirit or essential features of the present disclosure. The disclosed embodiments are illustrative and should not be interpreted restrictively.

Claims

1. A first light source that generates a first laser beam; A second light source that generates a second laser beam having a lower repetition rate than the first laser beam; A polarization converter that converts the polarization state of the second laser beam above into a radial state; A plurality of axicon lenses that convert the second laser beam, whose polarization state has been converted, into a Bessel beam; and A control module for controlling the first light source and the second light source; comprising The above control module is, A TGV (Through Glass Via) forming device that controls the timing of the emission of the first laser beam and the second laser beam so that the first laser beam is irradiated onto a glass substrate to generate plasma, and then the Bessel beam is irradiated to form a through hole.

2. In Paragraph 1, It further includes an AC power source that applies voltage to an IDT (interdigital transducer) element formed on the glass substrate, The above control module is, A TGV forming device that monitors changes in voltage measured by the above IDT element to inspect the condition of through holes formed in the glass substrate.

3. In Paragraph 2, The above control module is, A TGV forming device that determines that the through hole is normally formed when the voltage measured by the above IDT element decreases below a threshold voltage.

4. In Paragraph 1, The above control module is, A TGV forming device that controls the focal position formed by the Bessel beam by adjusting the distance between the plurality of axicon lenses.

5. In Paragraph 1, The above plurality of axicon lenses are, A TGV forming apparatus that generates the Bessel beam having multiple focal positions and provides the Bessel beam to multiple depth-direction focal positions of the glass substrate.

6. In Paragraph 1, A TGV forming device further comprising: a polarization beam splitter into which the first laser beam and the second laser beam, having mutually orthogonal polarization states, are incident, and which emits the first laser beam and the second laser beam along the same path to provide them to the polarization converter side.

7. A method for inspecting the processing state of a through hole using a TGV (Through Glass Via) forming device, A step of applying voltage to a first IDT (interdigital transducer) element formed on a glass substrate; A step of measuring voltage in a second IDT element formed between the first IDT element and a through hole; and An inspection method for inspecting the processing state of the through hole based on whether the above-mentioned measured voltage decreases.

8. In Paragraph 7, A step of generating plasma by irradiating a first laser beam onto the glass substrate; and An inspection method further comprising the step of forming a through hole by irradiating a second laser beam having a lower repetition rate than the first laser beam onto the glass substrate.

9. In Paragraph 8, The step of forming the above-mentioned through hole is, A step of generating a second laser beam having a repetition rate lower than that of the first laser beam; A step of converting the polarization state of the second laser beam above into a radial state; A step of converting the second laser beam, whose polarization state has been converted, into a Bessel beam; and An inspection method comprising the step of forming a through hole by irradiating the glass substrate with the Bessel beam.

10. In Paragraph 7, The step of inspecting the machining state of the above-mentioned through hole is, An inspection method comprising the step of determining the processing state of the through hole as normal when the above-mentioned measured voltage decreases below a threshold voltage.

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