阅读说明：本技术 玻璃基板通孔的激光加工方法和装置 (Laser processing method and device for glass substrate through hole ) 是由 张小军 彭裕国 苑学瑞 任莉娜 邱越渭 卢建刚 尹建刚 高云峰 于 2019-12-04 设计创作，主要内容包括：本发明属于激光加工的技术领域,特别是涉及一种玻璃基板通孔的激光加工方法和装置。该玻璃基板通孔的激光加工方法包括通过贝塞尔光束发生单元将激光器发射的第一激光束分离为对称且具有贝塞尔分布的第一光束和第二光束；再通过聚焦单元进行聚焦,生成具有预设聚焦光斑和预设焦深的加工激光束；令加工激光束在玻璃基板上以预设加工路径进行扫描；将扫描之后的所述玻璃基板放置在预设的腐蚀性溶液中；在预设时间之后自所述腐蚀性溶液中取出沿所述预设加工路径形成通孔的所述玻璃基板。本发明的玻璃基板通孔的激光加工方法,时间成本低,效率高且通孔质量好。(The invention belongs to the technical field of laser processing, and particularly relates to a laser processing method and device for a glass substrate through hole. The laser processing method of the glass substrate through hole comprises the steps of separating a first laser beam emitted by a laser into a first beam and a second beam which are symmetrical and have a Bezier distribution through a Bezier beam generating unit; focusing by a focusing unit to generate a processing laser beam with a preset focusing spot and a preset focal depth; scanning the processing laser beam on the glass substrate by a preset processing path; placing the scanned glass substrate in a preset corrosive solution; and taking out the glass substrate with the through hole formed along the preset processing path from the corrosive solution after a preset time. The laser processing method of the glass substrate through hole has the advantages of low time cost, high efficiency and good through hole quality.)

1. A laser processing method of a glass substrate through hole is characterized by comprising the following steps:

separating a first laser beam emitted by a laser into a first beam and a second beam which are symmetrical and have a Bezier distribution by a Bezier beam generation unit;

focusing the first light beam and the second light beam through a focusing unit to generate a processing laser beam with a preset focusing light spot and a preset focal depth;

scanning the processing laser beam on a glass substrate by a preset processing path so as to form a plurality of points with preset intervals on the glass substrate along the preset processing path;

placing the scanned glass substrate in a preset corrosive solution, so that the position of the point on the glass substrate is corroded by the corrosive solution at a corrosion speed which is higher than that of other positions on the glass substrate which are not scanned by the processing laser beam;

and taking out the glass substrate with the through hole formed along the preset processing path from the corrosive solution after a preset time.

2. The method for laser processing of a through hole of a glass substrate according to claim 1, wherein the splitting of the first laser beam emitted by the laser into the first beam and the second beam which are symmetrical and have a bessel distribution by the bessel beam generating unit comprises:

a first laser beam having a gaussian distribution generated by a laser;

diffusing the first laser beam through a concave mirror, and concentrating the diffused first laser beam into a parallel and diffused second laser beam through a convex mirror; the concave mirror and the convex mirror are arranged in parallel;

the parallel and divergent second laser beam is perpendicularly incident to the Bezier beam generation unit to split the second laser beam into first and second beams that are symmetrical and have a Bezier distribution by the Bezier beam generation unit.

3. The method for laser processing a through hole of a glass substrate according to claim 2, wherein the perpendicularly injecting the second laser beam, which is parallel and divergent, into the bessel beam generation unit includes:

perpendicularly injecting the parallel and divergent second laser beam into a spiral phase plate; the spiral phase plate and the convex mirror are arranged in parallel;

and vertically injecting the second laser beam transmitted by the spiral phase plate into the Bessel beam generation unit.

4. The laser processing method of a glass substrate through hole according to claim 1, wherein the laser is an ultra-short pulse laser, the wavelength of the first laser beam emitted by the ultra-short pulse laser is 300nm to 1100nm, the pulse width is 300fs to 50000fs, the repetition frequency is 10KH to 200KH, the single pulse energy is 10uJ to 1000uJ, and the power of the ultra-short pulse laser is 1W to 100W.

5. The laser processing device for the through hole of the glass substrate is characterized by comprising a laser, a Bessel beam generating unit, a focusing unit and a control module;

the laser is used for emitting a first laser beam;

the Bezier beam generation unit is used for separating a first laser beam emitted by a laser into a first beam and a second beam which are symmetrical and have a Bezier distribution;

the focusing unit is used for focusing the first light beam and the second light beam to generate a processing laser beam with a preset focusing light spot and a preset focal depth;

the control module is used for controlling the processing laser beam to scan on a glass substrate by a preset processing path so as to form a plurality of points with preset intervals on the glass substrate along the preset processing path;

controlling a preset grabbing device to place the scanned glass substrate in a preset corrosive solution, so that the position of the point on the glass substrate is corroded by the corrosive solution at a corrosion speed which is higher than that of other positions on the glass substrate which are not scanned by the processing laser beam;

and controlling the grabbing device to take out the glass substrate with the through hole formed along the preset processing path from the corrosive solution after a preset time.

6. The glass substrate through-hole laser processing device of claim 5, further comprising a beam expanding and collimating unit, wherein the beam expanding and collimating unit comprises a convex mirror and a concave mirror which are arranged in parallel; the concave mirror diffuses the first laser beam, the convex mirror concentrates the diffused first laser beam into a parallel and divergent second laser beam, and the second laser beam vertically enters the Bessel beam generation unit.

7. The apparatus of claim 6, wherein the beam expanding and collimating unit further comprises a spiral phase plate disposed parallel to the convex mirror, the second laser beam is perpendicularly incident on the spiral phase plate, and the second laser beam transmitted through the spiral phase plate is perpendicularly incident on the Bessel beam generating unit.

8. The apparatus for laser processing of a through hole of a glass substrate as claimed in claim 5, wherein the focusing unit comprises a first focusing unit and a second focusing unit arranged in parallel, and a distance between the first focusing unit and the second focusing unit is a sum of a focal length of the first focusing unit and a focal length of the second focusing unit.

9. The apparatus of claim 5, further comprising a base, a vision monitoring component for monitoring the processing state of the glass substrate scanned by the processing laser beam, and a movement component for driving the glass substrate to rotate and translate, wherein the laser, the Bessel beam generation unit, the focusing unit, the glass substrate, and the beam expansion and collimation unit are all mounted on the base, and the movement component is disposed at an end of the glass substrate far away from the focusing unit.

10. The apparatus for laser processing of a through hole in a glass substrate according to claim 5, wherein the Bessel beam generating unit is an axicon.

Technical Field

The invention belongs to the technical field of laser processing, and particularly relates to a laser processing method and device for a glass substrate through hole.

Background

Through Silicon Via (TSV) technology and Through Glass Via (TGV) technology break the bottleneck of two-dimensional chips, vertical connection between chips is realized by filling conductor materials in through holes, the performance of the chips is remarkably improved, the power consumption of the chips is reduced, and the packaged size of the chips is reduced. Because the manufacturing cost of the silicon substrate is higher, the glass has the thermal expansion coefficient which is equivalent to that of the silicon, the price is low, the process compatibility is high, and the glass becomes a research hotspot of people more and more.

At present, the laser processing method of the glass through hole mainly comprises the following steps: laser ablation, excimer laser drilling, laser induced etching, and the like. The laser ablation method is a method for forming holes on the surface of a glass material by ablating through femtosecond and nanosecond pulsed laser, but the laser ablation hole forming method has the defects that only a single hole can be formed, the time cost is high, and the thermal effect in the laser hole forming process can cause damage such as microcracks on the hole wall and the like to influence metal filling; the excimer laser punching method is a method for obtaining through holes by directly destroying molecular bonds of a glass material when high-energy photons are irradiated on the glass material, the excimer laser can process high-density through holes on glass with the thickness of 30-700 mu m, but the through holes are conical, so that subsequent filling of conductor materials is influenced, and as with laser ablation, a plurality of through holes are difficult to simultaneously manufacture, and the time cost is high; the laser induced etching method changes the structure of the corresponding position by focusing laser on the target position of the glass substrate, the etching rate is far greater than that of an unmodified area, and the unmodified area is etched and removed in a chemical mode.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the processing method of the glass through hole in the prior art has the problems of high manufacturing difficulty, high time cost, low processing efficiency and the like, and provides a laser processing method and device of the glass substrate through hole.

In view of the above problems, an embodiment of the present invention provides a method for laser processing a through hole in a glass substrate, including:

separating a first laser beam emitted by a laser into a first beam and a second beam which are symmetrical and have a Bezier distribution by a Bezier beam generation unit;

focusing the first light beam and the second light beam through a focusing unit to generate a processing laser beam with a preset focusing light spot and a preset focal depth;

scanning the processing laser beam on a glass substrate by a preset processing path so as to form a plurality of points with preset intervals on the glass substrate along the preset processing path;

placing the scanned glass substrate in a preset corrosive solution, so that the position of the point on the glass substrate is corroded by the corrosive solution at a corrosion speed which is higher than that of other positions on the glass substrate which are not scanned by the processing laser beam;

and taking out the glass substrate with the through hole formed along the preset processing path from the corrosive solution after a preset time.

Preferably, the splitting of the first laser beam emitted by the laser into the first and second beams which are symmetrical and have a bessel distribution by the bessel beam generating unit includes:

a first laser beam having a gaussian distribution generated by a laser;

diffusing the first laser beam through a concave mirror, and concentrating the diffused first laser beam into a parallel and diffused second laser beam through a convex mirror; the concave mirror and the convex mirror are arranged in parallel;

the parallel and divergent second laser beam is perpendicularly incident to the Bezier beam generation unit to split the second laser beam into first and second beams that are symmetrical and have a Bezier distribution by the Bezier beam generation unit.

Preferably, the perpendicularly injecting the parallel and divergent second laser beam into the bessel beam generation unit includes:

perpendicularly injecting the parallel and divergent second laser beam into a spiral phase plate; the spiral phase plate and the convex mirror are arranged in parallel;

and vertically injecting the second laser beam transmitted by the spiral phase plate into the Bessel beam generation unit.

Preferably, the laser is an ultrashort pulse laser, the wavelength of the first laser beam emitted by the ultrashort pulse laser is 300nm to 1100nm, the pulse width is 300fs to 50000fs, the repetition frequency is 10KH to 200KH, the single pulse energy is 10uJ to 1000uJ, and the power of the ultrashort pulse laser is 1W to 100W.

The embodiment of the invention also provides a laser processing device for the through hole of the glass substrate, which comprises a laser, a Bessel beam generating unit, a focusing unit and a control module;

the laser is used for emitting a first laser beam;

the Bezier beam generation unit is used for separating a first laser beam emitted by a laser into a first beam and a second beam which are symmetrical and have a Bezier distribution;

the focusing unit is used for focusing the first light beam and the second light beam to generate a processing laser beam with a preset focusing light spot and a preset focal depth;

the control module is used for controlling the processing laser beam to scan on a glass substrate by a preset processing path so as to form a plurality of points with preset intervals on the glass substrate along the preset processing path;

controlling a preset grabbing device to place the scanned glass substrate in a preset corrosive solution, so that the position of the point on the glass substrate is corroded by the corrosive solution at a corrosion speed which is higher than that of other positions on the glass substrate which are not scanned by the processing laser beam;

and controlling the grabbing device to take out the glass substrate with the through hole formed along the preset processing path from the corrosive solution after a preset time.

Preferably, the laser processing device for the glass substrate through hole further comprises a beam expanding and collimating unit, wherein the beam expanding and collimating unit comprises a convex mirror and a concave mirror which are arranged in parallel; the concave mirror diffuses the first laser beam, the convex mirror concentrates the diffused first laser beam into a parallel and divergent second laser beam, and the second laser beam vertically enters the Bessel beam generation unit.

Preferably, the beam expanding and collimating unit further includes a spiral phase plate disposed in parallel with the convex mirror, the second laser beam perpendicularly enters the spiral phase plate, and the second laser beam transmitted by the spiral phase plate perpendicularly enters the bessel beam generating unit.

Preferably, the focusing unit comprises a first focusing unit and a second focusing unit which are arranged in parallel, and the distance between the first focusing unit and the second focusing unit is the sum of the focal length of the first focusing unit and the focal length of the second focusing unit.

Preferably, the laser processing device for the glass substrate through hole further comprises a base, a visual monitoring assembly for monitoring the processing state of the glass substrate when scanned by the processing laser beam, and a moving assembly for driving the glass substrate to rotate and translate, wherein the laser, the bessel beam generation unit, the focusing unit, the glass substrate and the beam expansion collimation unit are all mounted on the base, and the moving assembly is arranged at one end, far away from the focusing unit, of the glass substrate.

Preferably, the bessel beam generation unit is an axicon.

According to the laser processing method for the glass substrate through hole, the Bessel beam generating unit is used for converting the laser beam with Gaussian distribution emitted by the laser into the Bessel beam, and the focal length of the Bessel beam is changed through the focusing effect of the focusing unit to enable the Bessel beam to become the processing laser beam with the preset focusing light spot and the preset focal depth (the focusing light spot is smaller and the focal depth is longer). The processing laser beam scans on the glass substrate, so that the etching speed of the area scanned by the center point of the processing laser beam on the glass substrate is higher than that of the area not scanned, and a circular through hole is formed on the glass substrate through soaking and etching the subsequent glass substrate in an etching solution. The Bessel beam has the characteristic of longer focal depth, so that the taper of the through hole formed on the glass substrate is small, and the quality of the through hole on the glass substrate is ensured; the multiple holes can be processed on the glass substrate at one time by utilizing the Bessel beam, so that the time cost is reduced, and the laser drilling efficiency is improved.

Drawings

The invention is further illustrated with reference to the following figures and examples.

Fig. 1 is a schematic view of a laser processing method for a through hole of a glass substrate according to an embodiment of the present invention;

fig. 2 is a flowchart illustrating step S10 of a method for laser processing a through hole in a glass substrate according to an embodiment of the present invention;

fig. 3 is a flowchart illustrating step S10 of a method for laser processing a through hole in a glass substrate according to another embodiment of the present invention;

fig. 4 is a schematic structural diagram of a laser processing apparatus for processing a through hole of a glass substrate according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a laser processing apparatus for processing a through hole of a glass substrate according to another embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a laser processing apparatus for processing a through hole of a glass substrate according to yet another embodiment of the present invention;

fig. 7 is a schematic view of a processing laser beam on a glass substrate according to a laser processing method for a through hole of a glass substrate provided in an embodiment of the present invention;

FIG. 8 is a schematic view of a processing laser beam on a glass substrate in a laser processing method for a via hole of a glass substrate according to another embodiment of the present invention;

fig. 9 is a schematic view illustrating a laser beam passing through an axicon in a method for laser processing a through hole of a glass substrate according to an embodiment of the present invention.

The reference numerals in the specification are as follows:

1. a laser 1; 2. a Bessel beam generating unit; 3. a focusing unit; 31. a first focusing unit; 32. a second focusing unit; 4. a first laser beam; 41. a first light beam; 42. a second light beam; 5. processing a laser beam; 6. a second laser beam; 7. a beam expanding and collimating unit; 71. a concave mirror; 72. a convex mirror; 73. a helical phase plate; 8. a glass substrate; 91. a base; 92. and a motion assembly.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It is to be understood that the terms "upper", "lower", "left", "right", "front", "rear", "middle", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the present invention.

As shown in fig. 1, a method for laser processing a through hole of a glass substrate according to an embodiment of the present invention includes:

s10, the first laser beam 4 emitted by the laser 1 is split into the first beam 41 and the second beam 42 which are symmetrical and have a bessel distribution by the bessel beam generating unit 2. It is understood that the first laser beam 4 is a laser beam having a gaussian distribution, that is, the amplitude of the laser cross section of the first laser beam 4 satisfies a gaussian function, and the first beam 41 and the second beam 42 are spatially conical laser beams in horizontal cross section, that is, the first beam 41 and the second beam 42 are an integral laser beam and are bessel beams, and the bessel beams are characterized by having a central spot, which remains unchanged for a long distance, thereby facilitating laser processing.

S20, the first light beam 41 and the second light beam 42 are focused by the focusing unit 3 to generate the processing laser beam 5 with a preset focusing spot and a preset focal depth. It is understood that the processing laser beam 5 is a zero-order bessel beam, the processing laser beam 5 has a small spot and a long focal depth, and the focal depth is advantageous in that a very deep glass hole can be processed at the focal position of the glass substrate 8 at one time.

Specifically, the focusing unit 3 is a convex lens, and the focusing unit 3 focuses the first light beam 41 and the second light beam 42 to obtain the processing laser beam 5 (with a smaller light spot and a longer focal depth); in an embodiment, as shown in fig. 6, the focusing unit 3 may be a convex lens, and the processing laser beam 5 is obtained by the focusing action of the convex lens on the first beam 41 and the second beam 42.

In another embodiment, as shown in fig. 4 and 5, the focusing unit 3 may be two convex lenses, and the distance between the two convex lenses is the sum of the focal lengths of the two convex lenses, when the two convex lenses constitute an optical 4F system, the first light beam 41 and the second light beam 42 pass through the optical 4F system, which is equivalent to fourier transform and then inverse fourier transform, so as to change the focal depth of the first light beam 41 and the second light beam 42 into the processing laser beam 5 with the preset focal depth.

S30, scanning the processing laser beam 5 on the glass substrate 8 along a predetermined processing path to form a plurality of points with a predetermined distance along the predetermined processing path on the glass substrate 8. It is understood that the etching speed of the area of the glass substrate 8 scanned by the processing laser beam 5 (i.e., a plurality of spaced points on a preset processing path) is greater than the etching speed of the unscanned area of the bessel beam.

In an embodiment, as shown in fig. 4 and 5, the focusing unit 3 is two convex lenses, and the two convex lenses constitute an optical 4F system, when the glass substrate 8 is placed on the focusing plane of the processing laser beam 5 (the focusing plane after the first beam 41 and the second beam 42 are focused by the two convex lenses), as shown in fig. 7, a light spot having a central point is generated on the glass substrate 8, and a through hole is formed at the central point of the light spot of the glass substrate 8 after etching in an etching solution, the method is suitable for processing a through hole with a relatively small diameter on the glass substrate 8; when the glass substrate 8 is placed before or after the focusing plane of the processing laser beam 5 (the focusing plane after the first beam 41 and the second beam 42 are focused by the two convex lenses), as shown in fig. 8, an annular light spot is generated on the glass substrate 8, and a through hole is formed at the annular light spot of the glass substrate 8 after the subsequent etching in the corrosive solution, and the method is suitable for processing a through hole with a relatively large diameter on the glass substrate 8.

In another embodiment, as shown in fig. 6, the focusing unit 3 is a convex lens, and when the glass substrate 8 is placed on the focusing plane of the processing laser beam 5 (the focusing plane after the first beam 41 and the second beam 42 are focused by the convex lens), the processing laser beam 5 forms an annular spot on the glass substrate 8, as shown in fig. 8, when the etching speed of the area of the glass substrate 8 scanned by the processing laser beam 5 is higher; when the glass substrate 8 is placed before or after the focusing plane of the processing laser beam 5 (the focal plane after the first beam 41 and the second beam 42 are focused by a convex lens), the processing laser beam 5 also forms an annular spot on the glass substrate 8, and it is understood that the etching rate of the area of the glass substrate 8 scanned by the processing laser beam 5 is small, as shown in fig. 8. Both of the glass substrate 8 placement schemes in this embodiment can be used to process through holes with relatively large diameters.

S40, placing the scanned glass substrate in a preset corrosive solution, so that the position of the point on the glass substrate 8 is corroded by the corrosive solution at a corrosion rate higher than the corrosion rate of other positions on the glass substrate 8 not scanned by the processing laser beam 5. Specifically, the corrosive solution is a mixed solution of hydrofluoric acid and hydrochloric acid, but is not limited thereto; it is understood that, since the etching speed of the area of the glass substrate 8 scanned by the processing laser beam 5 (i.e. the points with a plurality of intervals on the preset processing path) is greater than the etching speed of the area not scanned by the bessel beam, the glass substrate 8 is further etched by the etching solution, so that the points on the glass substrate 8 are further etched and enlarged to finally form the through hole, and other parts of the glass substrate 8 not scanned by the processing laser beam 5 are also etched, but are not etched through.

And S50, taking out the glass substrate 8 with the through hole formed along the preset processing path from the corrosive solution after a preset time. As can be understood, after the plurality of spaced points on the glass substrate 8 scanned by the processing laser beam 5 are etched through, through holes are formed on the glass substrate 8; when the area scanned by the processing laser beam 5 on the glass substrate 8 is a central light spot (as shown in fig. 4 and 5, the corresponding glass substrate 8 is placed on the focusing plane of the focusing unit 3 composed of two convex lenses), the glass substrate 8 is etched in the corrosive solution to form a through hole (a through hole with a smaller diameter) at the central light spot, as shown in fig. 7; when the area scanned by the processing laser beam 5 on the glass substrate 8 is an annular light spot (as shown in fig. 6, the corresponding glass substrate 8 is placed before or after the focal plane of the focusing unit 3 composed of two convex lenses, or is placed at any position of the focusing unit 3 composed of one convex lens), the glass substrate 8 is etched in the corrosive solution to form a through hole (a through hole with a larger diameter) at the annular light spot, as shown in fig. 8.

To explain further, the laser beam with gaussian distribution generated by the laser 1 is perpendicularly incident to the bessel beam generation unit 2 with the diameter d; the converging beam with the diameter d forms a zero-order bessel beam after passing through the bessel beam generating unit 2, the cross-section light spot distribution diagram is shown in fig. 4, and the beam diameter ρ of the bessel beam satisfies the following relation:

wherein, as shown in fig. 9, k is the wavevector; alpha is alpha₀The divergence angle of the light beam is determined by a Bessel generating unit; n is a refractive index of the bessel beam generation unit 2; n is₀Is the refractive index of its surroundings; tau is a characteristic parameter of the Bessel generation unit, and if the Bessel generation unit is an axicon, tau is a vertex angle of the axicon; when the Bessel beam is vertically incident on the focusing unit 3, the diameter of the focused beam is determined by the focusing unit 3. As can be seen from the above equation, the beam and the focal depth of the bessel beam are determined in cooperation with the size of the incident laser beam having the gaussian distribution, the bessel beam divergence angle, and the bessel beam generation unit 2.

Through the laser processing method of the through hole of the glass substrate 8, the through hole without taper and edge collapse can be processed on the glass substrate 8, namely the processing quality of the through hole is good; through holes with the diameter smaller than 30 micrometers can be machined in the glass substrate 8, the focused light spots of the machining laser beams 5 are extremely small, the roundness is high, and the reliability and the quality of mass production machining of small-size micropores are guaranteed; the method can process a plurality of through holes on the glass substrate 8 at one time, ensures that a product designer carries out unique design according to the requirement of the product designer, and greatly improves the efficiency, quality and reliability of mass production of the glass through holes. In addition, the laser processing method of the glass substrate through hole utilizes the Bessel beam to process the through hole on the glass substrate 8, the Bessel beam has the characteristic of long focal depth, and the deeper through hole can be processed on the glass substrate 8 at one time, compared with the existing laser induced corrosion method which utilizes the Gaussian light to irradiate and punch a layer by layer on the glass substrate 8, the efficiency of punching on the glass substrate 8 is greatly improved. In addition, compared with the existing ablation hole-forming technology (only one small point can be processed by each laser scanning, and the through hole can be formed by multiple times of scanning), the laser processing method of the glass substrate through hole can scan multiple corrosion points on the glass substrate 8 at one time, and finally forms the through hole by corrosion, so that the laser processing method of the glass substrate through hole has higher punching efficiency on the glass substrate 8.

In an embodiment, as shown in fig. 2, the step S10 (i.e. the separation of the first laser beam 4 emitted by the laser 1 into the first beam 41 and the second beam 42 which are symmetrical and have the bessel distribution by the bessel beam generation unit 2) includes:

s101, a first laser beam 4 having a gaussian distribution generated by the laser 1. It can be understood that the first laser beam 4 generated by the laser 1 is too concentrated, which results in that the first beam 41 and the second beam 42 (both zero-order bessel beams) generated by the bessel beam generating unit 2 are not very effective, so that the first laser beam 4 needs to be diffused to improve the effect of the bessel beam generating unit 2 on generating the first beam 41 and the second beam 42.

S102, diffusing the first laser beam 4 through the concave mirror 71, and concentrating the diffused first laser beam 4 into a parallel and divergent second laser beam 6 through the convex mirror 72; the concave mirror 71 and the convex mirror 72 are arranged in parallel. The distance between the concave mirror 71 and the convex mirror 72 may be determined according to the actual through hole formed in the glass substrate 8.

S103, perpendicularly injecting the parallel and divergent second laser beam 6 into the bessel beam generation unit 2, so as to split the second laser beam 6 into the first beam 41 and the second beam 42 which are symmetrical and have bessel distribution through the bessel beam generation unit 2. It is understood that the first laser beam 4 diffused by the concave mirror 71 is condensed by the structure of the convex mirror 72 and is incident perpendicularly to the bessel beam generation unit 2.

In another embodiment, as shown in fig. 3, step S103 (i.e. perpendicularly injecting the parallel and divergent second laser beam 6 into the bessel beam generation unit 2) includes:

s104, vertically injecting the parallel and divergent second laser beam 6 into the spiral phase plate 73; the helical phase plate 73 and the convex mirror 72 are arranged in parallel. Wherein the distance between the helical phase plate 73 and the convex mirror 72 is not required.

And S105, vertically injecting the second laser beam 6 transmitted by the spiral phase plate 73 into the Bessel beam generation unit 2.

It can be understood that, by the action of the spiral phase plate 73, the zero-order bessel beam is converted into a first-order bessel beam (the property of the processing laser beam 5 is changed), the first-order bessel beam is focused by the focusing unit 3 to obtain the processing laser beam 5 (first-order bessel beam) with a preset focusing spot and a preset focusing depth, and the processing through hole of the processing laser beam on the glass substrate 8 is the same as the processing laser beam 5 formed by the zero-order bessel beam through the focusing unit 3, and is not described herein again. The spiral phase plate 73 can eliminate the influence of the side lobe of the bessel beam on the processing laser beam 5, namely, the first-order bessel beam has the characteristics of anti-scattering and self-healing, and the appearance of a light spot can be kept well at the deeper position of the glass substrate 8, so that the processing quality (small taper) of the through hole on the glass substrate 8 is further improved.

In an embodiment, the laser 1 is an ultrashort pulse laser, the wavelength of the first laser beam 4 emitted by the ultrashort pulse laser 1 is 300nm to 1100nm, the pulse width is 300fs to 50000fs, the repetition frequency is 10KH to 200KH, the single-pulse energy is 10uJ to 1000uJ, and the power of the ultrashort pulse laser is 1W to 100W. Understandably, the laser pulse width of the first laser beam 4 emitted by the ultrashort pulse laser is small, so that the processing heat affected zone of the processing laser beam 5 is small, and further the processing quality of the through hole on the glass substrate 8 is improved; in addition, the processing laser beam 5 processes a through hole on the glass substrate 8, and the corresponding processing laser beam 5 includes, but is not limited to, processing of a glass through hole.

As shown in fig. 4, a laser processing apparatus for processing a through hole of a glass substrate according to an embodiment of the present invention includes a laser 1, a bessel beam generating unit 2, a focusing unit 3, and a control module (not shown); specifically, the bessel beam generation unit 2, the focusing unit 3 and the glass substrate 8 are sequentially distributed on a propagation path of laser light emitted by the laser 1; preferably, the bessel beam generation unit 2 is an axicon, but is not limited to an axicon.

The laser 1 is used for emitting a first laser beam 4; preferably, the laser 1 is an ultrashort pulse laser, and the common amount thereof is described above and will not be described herein again.

The bessel beam generation unit 2 is used for splitting the first laser beam 4 emitted by the laser 1 into a first beam 41 and a second beam 42 which are symmetrical and have a bessel distribution; the focusing unit 3 is configured to focus the first light beam 41 and the second light beam 42 to generate a processing laser beam 5 having a preset focusing spot and a preset focal depth; it can be understood that the first laser beam 4 emitted by the laser 1 is a laser beam with gaussian distribution which is not satisfactory for processing a through hole on the glass substrate 8, and the first laser beam 4 forms a first beam 41 and a second beam 42 (both zero-order bessel beams) with a certain focal depth after passing through the bessel beam generation unit 2, which initially meets the requirements of laser processing; the first light beam 41 and the second light beam 42 are focused by the focusing unit 3 to obtain the processing laser beam 5 (zero-order bessel beam) with a preset light spot and a preset focal depth, and the processing laser beam 5 has a small light spot and a long focal depth.

The control module is used for controlling the processing laser beam 5 to scan on a glass substrate 8 in a preset processing path, so that a plurality of points with preset intervals are formed on the glass substrate 8 along the preset processing path; it is understood that the control module controls the angular velocity (or the moving velocity) of the rotation of the glass substrate 8, in combination with the frequency (the number of times the pulse is repeated in one second) of the processing laser beam 5, so that a plurality of dots having a predetermined pitch (the scanning region of the processing laser beam 5) having an erosion rate greater than that of the non-scanning region of the processing laser beam 5 can be obtained on the glass substrate 8.

Controlling a preset grabbing device (not shown) to place the scanned glass substrate 8 in a preset corrosive solution, so that the position of the point on the glass substrate 8 is corroded by the corrosive solution at a corrosion speed which is greater than that of other positions, which are not scanned by the processing laser beam 5, on the glass substrate 8; it is understood that the gripping device may be a robot, and the control unit controls the gripping device to place the glass substrate 8 in the corrosive solution for dissolution, or alternatively, the gripping device may manually place the glass substrate 8 in the corrosive solution for dissolution.

And controlling the grabbing device to take out the glass substrate with the through hole formed along the preset processing path from the corrosive solution after a preset time. It is understood that, in the corrosive solution, a plurality of points (scanning regions of the processing laser beam 5) of the predetermined interval on the glass substrate 8 are etched through and enlarged, while a region of the glass substrate 8 which is not scanned by the processing laser beam 5 is not etched through, so that a through hole is formed in a predetermined processing path on the glass substrate 8.

Specifically, as shown in fig. 4, in the present embodiment, the laser beam emitted by the laser 1 has a wavelength of 1030nm, a single pulse energy of 50 μ J, a repetition frequency of 70kHZ, and a pulse width of 6 ps; the laser beam passes through an optical element group (Bessel beam generating unit 2 and the focusing unit 3) to generate a zero-order Bessel beam, and reaches the surface of the sample through the focusing unit 3; the machining laser beam 5 scans along a preset path in a dotting mode at a dot pitch of 200 μm, the size of a dot is equal to the size of a laser spot and is about 3 μm; compared with the material of an unprocessed area, the material of the scanning area of the processing laser beam 5 can be corroded by a corrosion solution more quickly, the glass substrate 8 after laser processing is placed in the corrosion solution for a period of time, the material in the scanning area of the processing laser beam 5 is corroded rapidly to form a through hole, the diameter of the through hole is larger than 50 micrometers, and meanwhile the glass substrate 8 becomes thin to be 0.11 mm.

In the invention, a laser beam with Gaussian distribution emitted by a laser 1 is converted into a Bessel beam through a Bessel beam generating unit 2, and the focal length of the Bessel beam is changed through the focusing action of a focusing unit 3 to form a processing laser beam 5 with a preset focusing spot and a preset focal depth (the focusing spot is smaller and the focal depth is longer). The processing laser beam 5 scans on the glass substrate 8, so that the etching speed of the area scanned by the central point of the processing laser beam 5 on the glass substrate 8 is higher than that of the area not scanned, and a circular through hole is formed on the glass substrate 8 through soaking and etching the subsequent glass substrate 8 in an etching solution. Because the Bessel beam has the characteristic of longer focal depth (the focal depth is longer, namely on a longer path of laser propagation, a clearer image is kept, and the processing is facilitated), the taper of the through hole formed on the glass substrate 8 is small, and the quality of the through hole on the glass substrate 8 is ensured; the Bessel beam can be used for processing multiple holes on the glass substrate 8 at one time, so that the time cost is reduced, and the laser drilling efficiency is improved.

In an embodiment, as shown in fig. 4, 5 and 6, the laser processing apparatus for a through hole of a glass substrate further includes a beam expanding and collimating unit 7, where the beam expanding and collimating unit 7 includes a convex mirror 72 and a concave mirror 71 that are arranged in parallel; the concave mirror 71 diffuses the first laser beam 4, the convex mirror 72 concentrates the diffused first laser beam 4 into a parallel and divergent second laser beam 6, and the second laser beam 6 is perpendicularly incident on the bessel beam generation unit 2. It is understood that the first laser beam 4 emitted from the laser 1 is dispersed by the divergent action of the concave mirror 71, and the dispersed first laser beam 4 is condensed by the convergent action of the convex mirror 72 to form the second laser beam 6 which is incident to the bessel beam generating unit 2 in parallel and perpendicularly. By the diffusion and expansion of the beam expanding and collimating unit 7 to the laser beam, the requirement on the laser 1 is reduced, namely the cost of the laser processing device for the through hole of the glass substrate 8 is reduced. In this embodiment, the diameter d of the laser beam incident on the bessel beam generation unit 2 is related to the divergence units (the convex mirror 72 and the concave mirror 71), thereby affecting the spot diameter and the focal depth of the machining laser beam 5.

In an embodiment, as shown in fig. 5 and fig. 6, the beam expanding and collimating unit 7 further includes a spiral phase plate 73 disposed parallel to the convex mirror 72, the second laser beam 6 is perpendicularly incident on the spiral phase plate 73, and the second laser beam 6 transmitted through the spiral phase plate 73 is perpendicularly incident on the bessel beam generating unit 2. It is understood that the processing laser beam 5 is converted from the zero-order bessel beam to a first-order bessel beam by the action of the spiral phase plate 73, and the processing through hole of the first-order bessel beam on the glass substrate 8 is the same as the processing laser beam 5 formed by the zero-order bessel beam through the focusing unit 3, and therefore, the description thereof is omitted here. The spiral phase plate 73 can eliminate the influence of the side lobe of the bessel beam on the processing laser beam 5, namely, the first-order bessel beam has the characteristics of anti-scattering and self-healing, and the appearance of a light spot can be kept well at the deeper position of the glass substrate 8, so that the processing quality (small taper) of the through hole on the glass substrate 8 is further improved.

Specifically, in the present embodiment, the operating parameters of the laser 1 are: the wavelength is 1030nm, the single pulse energy is 50 muJ, the repetition frequency is 70kHZ, the pulse width is 6ps, and a laser beam generates a first-order Bessel beam through an optical element group (a beam expanding and collimating unit 7, a Bessel beam generating unit 2, the focusing unit 3 and the like) and reaches the surface of a sample through the focusing unit 3; similarly, the first order bessel beam is scanned along a preset path in a manner of dotting at a dot pitch of 0.2mm on the glass substrate 8 to be processed with a thickness of 0.21mm, and the size of the dot is equal to the size of a laser spot and is about 3 μm; the processed glass substrate 8 was placed in an etching solution for a while, and the material in the laser irradiated region was rapidly etched to form through holes having a diameter of 50 μm while the glass substrate 8 was thinned to 0.11 mm.

In one embodiment, as shown in fig. 5, the focusing unit 3 includes a first focusing unit 31 and a second focusing unit 32 arranged in parallel, and a distance between the first focusing unit 31 and the second focusing unit 32 is a sum of a focal length of the first focusing unit 31 and a focal length of the second focusing unit 32. The first focusing unit 31 and the second focusing unit 32 are both convex lenses, and the distance between the first focusing unit 31 and the second focusing unit 32 is the sum of the focal length of the first focusing unit 31 and the focal length of the second focusing unit 32, at this time, the first focusing unit 31 and the second focusing unit 32 form a 4F system, and the light beam passes through the 4F system, which is equivalent to fourier transform and then fourier inverse transform, so that the focal depth of the bessel light beam is changed to be the processing laser beam 5 with the preset focal depth. It is understood that when the glass substrate 8 is placed at the focusing plane of the processing laser beam 5, a spot having a central point is generated on the glass substrate 8 as shown in fig. 7, and a through hole is formed at the central point of the spot by subsequent etching in an etching solution, the method is suitable for processing a through hole having a relatively small diameter; when the glass substrate 8 is placed before or after the focusing plane of the processing laser beam 5, an annular spot is generated on the glass substrate 8 as shown in fig. 8, and a through hole is formed at the annular spot by a subsequent operation, which is used for processing a through hole having a relatively large diameter.

Alternatively, as shown in fig. 6, the focusing unit 3 may be only the first focusing unit 31 (or the second focusing unit 32), in which case, the bessel beam emitted by the bessel beam generating unit 2 forms the processing laser beam 5 (i.e., the bessel beam) with a certain focal depth after passing through the first focusing unit 31 (or the second focusing unit 32); as can be understood, when the glass substrate 8 is placed at the focal plane of the first focusing unit 31 (or the second focusing unit 32), the processing laser beam 5 forms an annular spot on the glass substrate 8, where the etching speed of the area of the glass substrate 8 scanned by the processing laser beam 5 is large; when the glass substrate 8 is placed at a position before or after the focusing plane of the first focusing unit 31, the processing laser beam 5 also forms an annular spot on the glass substrate 8, but at this time, the etching speed of the region of the glass substrate 8 scanned by the processing laser beam 5 is small. The position of the glass substrate 8 can be selected according to the requirements of the actual glass through hole. In the present embodiment, the focusing unit 3 has only the first focusing unit 31 or the second focusing unit 32, and the beam size of the laser beam having the gaussian distribution with which the glass substrate 8 to be processed is placed on the focusing unit 3 (the first focusing unit 31 or the second focusing unit 32) is determined in common.

In an embodiment, as shown in fig. 4, the laser processing apparatus for processing a through hole of a glass substrate further includes a base 91, a visual monitoring component (not shown) for monitoring a processing state of the glass substrate 8 when scanned by the processing laser beam 5, and a moving component 92 for driving the glass substrate 8 to rotate and translate, wherein the laser 1, the bessel beam generating unit 2, the focusing unit 3, the glass substrate 8, and the beam expanding and collimating unit 7 are all mounted on the base 91, and the moving component 92 is disposed at an end of the glass substrate 8 away from the focusing unit 3. It can be understood that the monitoring component may be configured to monitor a processing state of the processing laser beam 5 during scanning on the glass substrate 8, monitor a condition of an optical path in a laser processing apparatus for a through hole of the glass substrate 8, and monitor a mounting condition of the laser 1, the bessel beam generation unit 2, the focusing unit 3, the glass substrate 8, and the beam expansion collimation unit 7 on the base 91, so as to further improve a processing accuracy of the through hole of the processing laser beam 5 on the glass substrate 8. Further, if a square through hole needs to be machined on the glass substrate 8, the moving assembly 92 controls the glass substrate 8 to move and rotate; if a circular through hole needs to be machined in the glass substrate 8, the moving assembly 92 controls the glass substrate 8 to rotate at a certain angular speed.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.