DEBRIS-FREE LASER ABLATION PROCESSING ASSISTED BY CONDENSED FROST LAYER

Abstract

Laser ablation processing method for debris-free and efficient removal of materials, using a refrigeration device to condense the water vapor and form a thin frost layer on the materials at temperatures below the freezing point. The residual debris deposits on the frost layer covered on the material during the ablation process, which is easily removed when the frost layer melts. At the same time, the frost layer in the laser irradiation area melts to a liquid layer, which can effectively reduce the deposition of debris on the inner wall of the groove and thus improve the efficiency and quality of laser ablation. The method is applicable to debris-free laser processing on an arbitrary curved surface.

Claims

1. A laser processing method, comprising: forming a frost layer by condensation on a surface of an object with a refrigeration device, irradiating a laser beam on the object through the frost layer to conduct ablation processing, and removing the frost layer by heating up the surface of the object, washing off the frost layer containing debris, and obtaining a laser ablation structure.

2. The laser processing method of claim 1, wherein, when the laser processing is a through-hole or cutting processing, thin layers of ice are formed on both sides of the object.

3. The laser processing method of claim 1, wherein the surface of the object is a plane or curved surface.

4. The laser processing method of claim 1, wherein the frost layer is formed by the condensation of gaseous substances on the surface of the object at low temperature, and thickness of the frost layer is between 0.5 m and 1 mm.

5. The laser processing method of claim 1, wherein the temperature of the surface of the object is between 0 C. and 40 C.

6. The laser processing method of claim 1, wherein the frost layer is formed by condensation of gaseous substances on the surface of the object at a low temperature, and the gaseous substances are water vapor, oil vapor, or combination thereof.

7. The laser processing method of claim 1, wherein the refrigeration device is a semiconductor refrigeration device, or an evaporation refrigeration device.

8. The laser processing method of claim 1, wherein material of the object comprises dielectric material, semiconductor material, glass, metal, or combination thereof.

9. The laser processing method of claim 1, wherein the object is processed for laser cutting, laser laying-out, laser marking, laser grooving, laser patterning, laser drilling, or combination thereof.

10. The laser processing method of claim 1, wherein the laser beam is a nanosecond laser, a picosecond laser, or a femtosecond laser.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 is a flow chart showing the frost layer assisted laser surface ablation in accordance with the first embodiment of the present invention.

[0033] FIG. 2 is a flow chart showing the frost layer assisted laser drilling in accordance with the second embodiment of the present invention.

[0034] Reference numbers used in these figures refer to the following structures:

[0035] 1-one-side refrigeration unit; 2-processing sample; 3-vapor; 4-frost layer; 5-focusing lens; 6-laser beam; 7-groove; 8-double-side refrigeration unit; 9-through hole.

DETAILED DESCRIPTION OF INVENTION

[0036] The present invention is further explained in details in connection with the following embodiments and drawings. It should be noted that the embodiments described below are intended to facilitate the understanding of the present invention, without creating any limitation on the invention.

[0037] In the first embodiment of the present invention as illustrated in FIG. 1, the method for grooving on the surface of sample to be processed comprises the following steps:

[0038] (1) A refrigeration device 1 is mounted on an X-Y translation stage controlled by computer, and then a sample 2 is fixed on the refrigeration device, so that the sample can move with the stage along a preset path. The outlet of a vapor 3 producing device with controlled temperature, humidity, and flow rate is positioned to face the surface of the sample. The temperature of the sample surface is controlled to be below the freezing point at 0 C. As a result, a frost layer 4 is formed by condensation on the surface of sample, and the thickness of the frost layer 4 can be controlled by adjusting the humidity and temperature of the environment, flow rate and flow amount, and the temperature of the sample surface. Preferably, the temperature of the surface of sample is controlled between 0 C. and 20 C.; and the thickness of the frost layer is 0.5 m to 1 mm.

[0039] (2) The above-mentioned parameters are precisely controlled to keep the thickness of the frost layer 4 unchanged. Subsequently, a laser beam 6 is focused on the sample 2 covered with frost layer 4 to realize the surface grooving under laser ablation. Under the laser irradiation, the frost layer 4 in the laser scanning area melts quickly, and a very thin liquid layer is produced in the groove 7. As a result, tiny bubbles is created in the liquid layer under the laser irradiation, and the subsequent rupture of the bubble helps to remove the debris from the inside of the groove 7. The frost layer 4 in the non-irradiated area can effectively avoid the deposition of debris around the ablation groove 7.

[0040] (3) The frost layer 4 mixed with debris was heated and washed out, and then high-quality groove structure is obtained.

[0041] In the second embodiment of the present invention as shown in FIG. 2, the method for drilling a through hole on the surface of sample is described, which comprises the following steps:

[0042] (1) A refrigeration device 8 is mounted on an X-Y translation stage controlled by computer, and then a sample 2 is fixed on the refrigeration device, so that the sample can move with the stage along a preset path. The temperature and humidity of the environment around the sample to be processed are controlled by an air conditioner, and the temperature of the sample surface is set at temperatures below the freezing point. As a result, two frost layers 4 are formed by condensation on both the front surface and the rear surface 3 of sample 2, and the thickness of the frost layer can be controlled by adjusting the humidity and temperature of the environment, and the temperature of the sample surface. Preferably, the temperature of the surface of sample is controlled between 0 C. and 20 C.; the thickness of the frost layer is 0.5 m to 1 mm.

[0043] (2) The above-mentioned parameters are precisely controlled to keep the thickness of the frost layer 4 unchanged. Subsequently, a laser beam 6 is focused on the sample 2 covered with the frost layer 4 to realize the drilling of through hole 9 with laser ablation. Under the laser irradiation, the frost layers 4 in the laser drilling area melts quickly, and a very thin liquid layer is produced in the hole 9. As a result, tiny bubbles are created in the liquid layer under the laser irradiation, and the subsequent rupture of the bubble help to remove the debris from the inside of the hole 9. In the area without laser irradiation, the frost layers on the front and rear surfaces of the sample play a role in collecting the debris during the drilling process, to avoid the deposition of debris on both the surfaces around the through hole 9.

[0044] (3) The frost layer 4 mixed with debris is heated and washed out, and then high-quality groove structure is obtained.

[0045] The embodiments of the present invention describe in details the technical scheme of the present invention, and they provide some specific examples but are not used to limit the scope of protection for the present invention. Any modification, supplement, or similar substituting way made within the scope of the principles of the present invention shall be included in the protection scope of the present invention.