CN112222630A

CN112222630A - Laser processing method

Info

Publication number: CN112222630A
Application number: CN201910559770.2A
Authority: CN
Inventors: 程正明; 宁玮; 袁从文; 杨建伟; 卢建刚; 孙杰; 尹建刚; 高云峰
Original assignee: Han s Laser Technology Industry Group Co Ltd
Current assignee: Han s Laser Technology Industry Group Co Ltd
Priority date: 2019-06-26
Filing date: 2019-06-26
Publication date: 2021-01-15

Abstract

The invention relates to the technical field of laser processing, in particular to a laser processing method which is used for processing a through hole on a product to be processed, wherein the cross section of the through hole is provided with a closed contour line, and the laser processing method comprises the following steps: the laser beam is focused on the product to be processed and moves along the contour line relative to the product to be processed, so that the product to be processed forms a modified region distributed along the contour line; and putting the product to be processed with the modified region into etching liquid, and etching the modified region by the etching liquid to enable the part in the contour line to fall off to form the through hole. According to the laser processing method, the product to be processed forms the modified region through the laser beam, and the product to be processed can be prevented from being processed by using a cutter, so that microcracks cannot be caused in the product to be processed, residual stress cannot be caused in the product to be processed, and the processing quality is high. When etching is performed by the etching solution, the etching solution can etch all the modified regions simultaneously, and the processing efficiency is high.

Description

Laser processing method

Technical Field

The invention relates to the technical field of laser processing, in particular to a laser processing method.

Background

In recent years, with rapid development of the internet and aggravation of market competition, consumer electronics products such as smart phones, tablet computers, liquid crystal televisions and the like are continuously upgraded in an iterative manner, and transparent materials such as glass, sapphire and the like are widely applied to various electronic products, particularly smart phones, such as 3D glass, fingerprint identification protection plates, camera protection cover plates and the like on the surfaces of the smart phones. Various holes are generally formed in the parts, and a finer punching process is needed along with the upgrading and updating of products.

At present, two machining methods, namely CNC machining and laser Ablation (Ablation) machining, are mainly adopted in the market. However, the conventional CNC processing method generally causes microcracks and residual internal stress inside the product to be processed, resulting in a reduction in the quality of the product. Particularly, when a hole with a high depth-diameter ratio is machined, the traditional CNC machining technology is low in efficiency, high in cost and even difficult to achieve. Although the laser ablation processing method can be used for processing holes with high depth-diameter ratio, the processing efficiency is low, and the production requirements of customers cannot be met.

Disclosure of Invention

The invention aims to provide a laser processing method, and aims to solve the problem that the traditional processing method cannot meet the requirements on processing quality and processing efficiency at the same time.

In order to solve the above problems, the present invention provides a laser processing method for processing a through hole on a product to be processed, wherein a cross section of the through hole has a closed contour line, the laser processing method comprising the steps of:

the laser beam is focused on the product to be processed and moves along the contour line relative to the product to be processed, so that the product to be processed forms a modified region distributed along the contour line; and

and putting the product to be processed with the modified region into etching liquid, and etching the modified region by the etching liquid to enable the part in the contour line to fall off to form the through hole.

Optionally, the product to be processed is of a flat plate structure.

Optionally, the thickness of the product to be processed is 0.1-10 mm.

Optionally, the laser beam is a long-focus depth focused laser beam, the length of a focusing line of the laser beam is 0.1-10 mm, and the diameter of a light spot of the laser beam is less than or equal to 5 μm.

Optionally, the wavelength of the laser beam is 300-1100 nm, the frequency is 0-1000 KHZ, and the pulse width is 100 fs-100 ps.

Optionally, the etching solution is an aqueous solution containing fluorine ions.

Optionally, the etching solution comprises hydrofluoric acid and nitric acid.

Optionally, the laser processing method further includes the steps of:

and taking the product to be processed out of the etching solution when the through hole is formed.

Optionally, the product to be processed has a plurality of irradiation points for irradiation of the laser beam, the plurality of irradiation points are uniformly distributed at intervals along the contour line, and a distance between two adjacent irradiation points is in a range of 0.1-20 μm.

Optionally, the through-hole is a circular hole, a square hole or a strip-shaped hole.

The embodiment of the invention has the following beneficial effects:

according to the laser processing method, the product to be processed forms the modified region through the laser beam, and the product to be processed can be prevented from being processed by using a cutter, so that microcracks cannot be caused in the product to be processed, residual stress cannot be caused in the product to be processed, and the processing quality is high. In addition, the speed of forming the modified region by the laser beam is higher than the speed of laser ablation, and the processing efficiency can be improved. In addition, when etching is performed by the etching solution, the etching solution can simultaneously etch all the modified regions, and the processing efficiency is high. Moreover, the edge of the through hole formed by etching the modified region by the etching solution is smooth, the taper is small, and the processing quality of the through hole can be further improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Wherein:

FIG. 1 is a schematic flow chart of a laser processing method according to one embodiment;

FIG. 2 is a schematic structural view of a product to be processed using the laser processing method of FIG. 1;

FIG. 3 is a schematic structural diagram of a modified region formed on the workpiece to be processed in FIG. 2;

fig. 4 is a schematic structural diagram of the product to be processed in fig. 2 after a through hole is formed.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, an embodiment of the present invention provides a laser processing method for processing a through hole 40 in a product 10 to be processed, and as shown in fig. 4, a cross section of the through hole 40 has a closed contour line 20. The laser processing method comprises the following steps:

step S1: the laser beam is focused on the product 10 to be processed and moves along the contour line 20 relative to the product 10 to be processed, so that the product 10 to be processed forms a modified region 30 distributed along the contour line 20, as shown in fig. 3;

step S2: the product 10 to be processed, on which the modified region 30 is formed, is placed in an etching solution, and the etching solution etches the modified region 30, so that the portion inside the contour line 20 falls off to form a through hole 40, as shown in fig. 4.

Specifically, when the laser beam is condensed on the product 10 to be processed, the laser beam can be irradiated to the inside of the product 10 to be processed, and chemical bonds of the irradiated portion of the product 10 to be processed are broken to form the modified region 30 in the thickness direction of the product 10 to be processed. The product to be processed 10 may be glass, quartz, sapphire, or the like. The laser beam is moved along the contour line 20 relative to the product 10 to be processed so that the modified regions 30 are formed along the contour line 20. When the workpiece 10 with the modified region 30 formed thereon is placed in the etching solution, the etching solution etches the modified region 30 at a rate much higher than other regions that are not modified, and the etching solution selectively chemically etches the workpiece 10. As the modified region 30 is etched, the product 10 to be processed forms a gap along the contour line 20 until the through hole 40 is formed after the portion inside the contour line 20 falls off.

As shown in fig. 2, the product 10 to be processed is a schottky 263T glass plate with a size of 100 × 100mm and a thickness of 0.5 mm. During the machining process, the laser beam moves along each contour line 20 relative to the product 10 to be machined to form a plurality of modified regions 30 on the product 10 to be machined, as shown in fig. 3. Then, the product 10 to be processed on which the modified region 30 is processed is put into the etching solution until the portion inside the contour line 20 falls off to form a plurality of through holes 40, as shown in fig. 4. Then, the product 10 to be processed, on which the through holes 40 are processed, is cut to form a product of a desired size. As can be understood, the through holes 40 are processed in advance on the product to be processed 10 with a larger size, and then the product is cut, so that the processing difficulty can be reduced, and the processing efficiency can be improved.

It should be noted that the present embodiment is described with a circular hole, and of course, in other embodiments, the through hole 40 may also be a square hole or a strip-shaped hole as long as the contour line 20 of the cross section of the through hole 40 is closed.

It is understood that the operator may program in advance and control the laser beam to machine the modified region 30 along the contour line 20 by the controller. Of course, in other embodiments, the product 10 to be processed may be placed on a processing platform, and the processing platform is controlled by the controller to move, and the position of the laser beam is kept unchanged, so that the laser beam moves along the contour line 20 relative to the product 10 to be processed.

In the laser processing method, the modified region 30 is formed in the product 10 to be processed by the laser beam, and the product 10 to be processed can be processed without using a tool, so that microcracks are not caused in the product 10 to be processed, stress is not left in the product 10 to be processed, and the processing quality is high. Further, the speed of forming the modified region 30 by the laser beam is higher than the speed of laser ablation, and the processing efficiency can be improved. In addition, when etching is performed by the etching solution, the etching solution can simultaneously etch all the modified regions 30, and the processing efficiency is high. In addition, the through hole 40 formed by etching the modified region 30 with the etching solution has a smooth edge and a small taper, and the processing quality of the through hole 40 can be further improved.

The through hole 40 processed by the laser processing method has the edge breakage smaller than 10 microns, the taper smaller than 1 degree, the size precision within the range of +/-5 microns, and the processing efficiency of a single hole larger than 50 mm/s.

It should be noted that, in the present embodiment, the product to be processed 10 is a flat plate structure, and the laser beam is perpendicularly irradiated on the product to be processed 10, so that the laser beam is irradiated into the interior of the product to be processed 10 as much as possible, so that the modified region 30 is formed in the interior of the product to be processed 10.

Further, in the embodiment, the thickness of the product 10 to be processed is 0.1-10 mm. By controlling the thickness of the product 10 to be processed, the depth of the modified region 30 can be ensured to be matched with the thickness of the product 10 to be processed, so that the part in the contour line 20 can fall off after the modified region 30 is etched by the etching solution, and the problem that the part in the contour line 20 cannot fall off after the modified region 30 is etched due to the over-thickness of the product 10 to be processed is avoided. Moreover, the product 10 to be processed within the thickness range is selected, and the laser beam moves once along the contour line 20, so that the modified region 30 matched with the thickness of the product 10 to be processed can be formed in the product 10 to be processed, and the deviation of the position of the modified region 30 caused by the reciprocating movement of the laser beam along the contour line 20 is avoided, thereby improving the processing precision of the through hole 40.

In this embodiment, the laser beam is a long focal depth focused laser beam, and the focal line length of the laser beam is 0.1mm to 10 mm. In this way, the laser beam can penetrate through the product 10 to be processed in the thickness direction of the product 10 to be processed, so that the depth of the modified region 30 is adapted to the thickness of the product 10 to be processed, thereby ensuring that the part in the contour line 20 can completely fall off after the modified region 30 is etched by the etching solution. Moreover, the spot diameter of the laser beam is less than or equal to 5 μm to ensure the energy density of the laser beam, so that the inside of the product 10 to be processed can form the modified region 30 adapted to the thickness of the product 10 to be processed by moving the laser beam once along the contour line 20. Further, the etching solution is an aqueous solution containing fluorine ions, and chemically reacts with the modified region 30 to etch the modified region 30.

In this embodiment, the etching solution includes a hydrofluoric acid solution and a nitric acid solution, the hydrofluoric acid solution has a volume percentage concentration of 5%, and the nitric acid solution has a volume percentage concentration of 7.5%. Of course, in other embodiments, the volume ratio of the hydrofluoric acid solution to the nitric acid solution may also be changed, for example, the hydrofluoric acid solution may also have a concentration of 10% by volume and the nitric acid solution may also have a concentration of 15% by volume. The nitric acid solution is mixed in the hydrofluoric acid solution, so that the ionization of fluorine ions can be promoted, and the etching speed of the etching solution is accelerated.

In other embodiments, the etching solution may also be a mixed solution of hydrochloric acid and sulfuric acid. Moreover, the etching solution can also comprise deionized water to ensure the etching effect of the etching solution.

It should be noted that the laser processing method of the present embodiment further includes step S3: the product 10 to be processed is taken out of the etching solution when the through hole 40 is formed. That is, when the portion inside the contour line 20 falls off and the to-be-processed product 10 forms the through hole 40, the to-be-processed product 10 should be immediately taken out of the etching solution to prevent the etching solution from further etching the to-be-processed product 10, thereby ensuring the processing accuracy of the through hole 40.

The position on the product to be processed 10 to which the laser beam is irradiated is referred to as an irradiation point. It is understood that the number of the irradiation points is plural, and the plural irradiation points are uniformly spaced along the contour line 20. After the laser beam irradiates each irradiation point, the product 10 to be processed forms a modified region 30 at a position corresponding to each irradiation point.

In the embodiment, the distance between two adjacent irradiation points is in the range of 0.1-20 μm. It is understood that when the distance between two adjacent irradiation points is small, the modified region 30 may spread to a position outside the contour line 20, thereby affecting the processing accuracy of the through hole 40. If the distance between two adjacent irradiation points is large, the product to be processed cannot form a continuous modified region 30 along the contour line 20. Thus, after the etching solution etches the modified region 30, the partial structure in the contour line 20 cannot be removed, and the through hole 40 cannot be formed.

Furthermore, the wavelength of the laser beam is 300-1100 nm, the frequency is 0-1000 KHZ, and the pulse width is 100 fs-100 ps. The long-focus deep-focusing laser beam can be formed by matching with a corresponding optical focusing system, the length of a focusing line of the laser beam is 0.1-10 mm, and the spot diameter of the laser beam is less than or equal to 5 mu m, so that the processing precision is improved.

In this embodiment, the laser beam has a wavelength of 1030nm, a pulse width of 8ps, and a single pulse energy of 250 μ j. The laser beam passes through the beam transmission system and the optical focusing system and then forms a long-focus-depth focusing beam which can penetrate through the material under the processing objective lens, and the length of the focusing line is more than 2 mm.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.

Claims

1. A laser processing method is used for processing a through hole on a product to be processed, the cross section of the through hole is provided with a closed contour line, and the laser processing method is characterized by comprising the following steps:

2. The laser processing method according to claim 1, wherein the product to be processed is a flat plate structure.

3. The laser processing method according to claim 2, wherein the thickness of the product to be processed is 0.1 to 10 mm.

4. The laser processing method according to claim 1 or 3, wherein the laser beam is a long focal depth focused laser beam, a focal line length of the laser beam is 0.1 to 10mm, and a spot diameter of the laser beam is less than or equal to 5 μm.

5. The laser processing method according to claim 1, wherein the laser beam has a wavelength of 300 to 1100nm, a frequency of 0 to 1000KHZ, and a pulse width of 100fs to 100 ps.

6. The laser processing method according to claim 1, wherein the etching liquid is an aqueous solution containing fluorine ions.

7. The laser processing method according to claim 6, wherein the etching solution contains hydrofluoric acid and nitric acid.

8. The laser machining method according to claim 1, further comprising the steps of:

9. The laser processing method according to claim 1, wherein the product to be processed has a plurality of irradiation points to which the laser beam is irradiated, the plurality of irradiation points are evenly distributed at intervals along the contour line, and a distance between two adjacent irradiation points is in a range of 0.1 to 20 μm.

10. The laser processing method according to claim 1, wherein the through-hole is a circular hole, a square hole, or a strip-shaped hole.