WO2018000974A1

WO2018000974A1 - Laser processing method and device for removing thin film or coating

Info

Publication number: WO2018000974A1
Application number: PCT/CN2017/084447
Authority: WO
Inventors: 陶沙; 赵晓杰; 秦国双
Original assignee: 英诺激光科技股份有限公司
Priority date: 2016-06-28
Filing date: 2017-05-16
Publication date: 2018-01-04
Also published as: WO2018000586A1; CN106077956B; CN106077956A

Abstract

A laser processing method for removing a thin film or a coating, comprising the following steps: first step, acquiring a thickness value of a thin film or a coating by means of measurement; second step, according to the thickness value acquired in the first step, adjusting a parameter of a laser; and third step, starting a laser device, and repeatedly performing the first step and the second step, so that the laser scans the surface of the thin film or the coating, until the thin film or the coating is removed. A certain thickness value or a related physical quantity value is pre-set as a reference, and preliminary processing is performed; and when the measured thickness of a thin film or a coating or the related physical quantity is consistent with a pre-set value, adjusting a processing parameter to perform fine processing, until the thin film or the coating is removed. Compared with the prior art, in the laser processing method and device for removing a thin film or a coating, the thickness of a thin film or a coating is measured in real time, and accordingly, a laser parameter is adjusted, so the present invention achieves the optimal removal effect, and is fast and accurate.

Description

Laser processing method and device for removing film or coating

Technical field

The invention relates to the field of film removal technology, in particular to a laser processing method and device for removing a film or a coating by using a laser.

Background technique

Process requirements for film or coating removal are often encountered during processing, such as by removing portions of the film or coating to create marks; by removing portions of the film or coating to achieve certain properties of the workpiece (eg, conductive, Insulation, light transmission, etc.; or coating a film or coating for protection during processing, the film or coating needs to be removed after some processes are completed. Since the film or coating is generally thin and has strong adhesion, it is difficult to achieve efficient and accurate removal by conventional mechanical means. The emergence of laser processing has solved this problem to a certain extent, but because the thickness of the film or coating is difficult to measure accurately, or the film itself is not uniform, it is difficult to ensure uniform thickness in every place, which leads to the film. Layers or coatings are difficult to remove efficiently and accurately.

Summary of the invention

It is an object of the present invention to provide a laser processing method and apparatus for removing a film or coating which solves the technical problem that it is difficult to efficiently and accurately remove a surface coating or film.

In order to achieve the above object, the technical solution proposed by the present invention is:

A laser processing method for removing a film or coating according to the present invention comprises the following steps:

In the first step, measuring the thickness value of the film or coating;

In the second step, adjusting the parameters of the laser according to the thickness value obtained in the first step;

In the third step, the laser is turned on, and the first step and the second step are repeated to make the laser in the film or The surface of the coating is scanned until the film or coating is removed.

Before performing the first step, the method further comprises: presetting a certain thickness value as a detection reference, using a uniform laser parameter, performing preliminary removal on the film or the coating, and detecting the feedback signal in real time until the film or the coating thickness The step of reaching the preset value and then adjusting the machining parameters according to the preset value for fine machining.

Wherein, obtaining the thickness value in the first step comprises the following steps:

In the first step, the power P of the laser before entering the film or coating and the power P' of the outgoing laser after being refracted from the film or coating are measured by a power detector;

In the second step, the power ratio of the power of the outgoing laser to the incident laser is calculated:

R ₁ is the incident surface reflectance of the incident laser, R ₂ is the reflectance of the reflective surface of the film or coating, R ₃ is the exit surface reflectance of the exiting laser, L is the transmission distance of the laser in the film or coating, and α is the laser The absorption coefficient of the beam within the film or coating;

In the third step, the thickness value t is calculated according to the L value obtained in the second step,

Where θ is the incident angle of the laser, n ₁ is the refractive index of the air medium, and n ₂ is the refractive index of the film or coating.

Wherein the obtaining the thickness value in the first step comprises the following steps:

In the first step, a dual-wavelength laser is selected to obtain the power ratio r of the output laser light of the dual-wavelength laser beam and the incident laser, respectively, which are denoted as r ₁ and r ₂ ;

In the second step, when the selected dual wavelengths are close, the reflectivity is similar, so

In this way, the L value can be obtained, and then the thickness value t can be calculated, wherein α ₁ and α ₂ are the absorption coefficients of the dual-wavelength laser in the film or the coating, respectively;

Wherein, in the step of obtaining the thickness value of the film or the coating, the detecting beam used may be from a laser light source for processing, or may be a light source of any wavelength. That is, the probe beam is of any wavelength and may be the same as or different from the processed laser wavelength. The processing laser needs to be selected according to the removed film or coating.

A laser processing apparatus for removing a film or a coating using the laser processing method for removing a film or a coating according to any of the above, comprising: a laser, an industrial computer controlling the laser, and sequentially arranged along a laser emission direction a beam expander, a galvanometer and a lens system; wherein the industrial computer is further provided with a power detector for detecting the laser light from the film or the coating in real time, and the power value obtained by the industrial computer according to the power detector is Calculate the thickness of the film or coating and adjust the laser parameters in real time to allow the laser to quickly and accurately remove the film or coating.

Wherein, the X-Y platform for placing the workpiece to be processed is further included, and the X-Y platform drives the workpiece to be moved to complete the removal of the surface film or coating of the workpiece to be processed.

The laser is further provided with a power detector for detecting the power of the laser to emit laser light in real time, and transmitting the power value to the industrial computer.

Wherein, the industrial computer adjusts the laser parameters of the laser, including: the output laser power, the laser frequency, the galvanometer scanning speed, the platform moving speed, and the processing times.

Compared with the prior art, the laser processing method and equipment for removing film or coating of the invention can measure the laser parameters according to the thickness by real-time measuring the thickness of the film or the coating, so as to achieve the optimal removal effect, fast and accurate.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram showing the structure of a laser processing apparatus for removing a film or a coating of the present invention.

2 is a flow chart of a laser processing method for removing a film or coating of the present invention.

3 is a schematic view showing the principle of obtaining thickness values of a laser processing method for removing a film or a coating according to the present invention.

Detailed ways

The invention is further elaborated below with reference to the accompanying drawings.

Referring to FIG. 2, in the embodiment, the laser processing method for removing a film or a coating comprises the following steps:

In the first step S1, the thickness value of the film or the coating is obtained by measuring; that is, the thickness of the film or the coating at different positions is obtained in real time by means of measurement or the like;

In the second step S2, the parameters of the laser are adjusted according to the thickness obtained in the first step; the parameters for adjusting the laser in the step include laser output laser power, laser frequency, galvanometer scanning speed, platform moving speed, processing times, etc., according to Thickness

In a third step S3, the laser is turned on, and the first step S1 and the second step S2 are repeated to scan the laser or the surface of the coating until the film or coating is removed. Since the thickness of the film or coating is inconsistent, the steps of detecting the thickness and adjusting the parameters need to be repeated throughout the removal process.

Wherein, since the thickness is inconsistent, the process of detecting and adjusting is required to be repeated in real time. Therefore, for some thick films or coatings, before the first step S1 is performed, the method further includes: setting a certain thickness value as a detection reference in advance. Using a uniform laser parameter, the film or coating is initially removed and the feedback signal is detected in real time until the thickness of the film or coating reaches a preset value, and then the processing parameters are adjusted according to preset values for fine processing. That is, the high-power is used to quickly remove the entire film or coating on the surface of the sample until the preset value is reached, so as to avoid the problem of long removal time and low efficiency due to repeated detection adjustment.

More specifically, there are two application methods for film removal: one is to obtain the thickness of the film before or during the processing through the information of the negative feedback, and then set the processing parameters to complete the processing; secondly, preset a negative feedback value, The value corresponds to the thickness of the remaining film. In actual processing, the high-speed processing is first performed, and the negative feedback signal is detected in real time. When the measured negative feedback signal value is consistent with the preset value, the final fine of the processing parameter is adjusted. machining.

The obtaining of the thickness value in the first step may be performed in the following two manners. Please refer to the schematic diagram of the laser removal principle in FIG.

In Figure 3: 1 incident beam, 2 transmission medium (typically air), 3 film or coating, 4 exit beam. Wavelength selection medium 2 in a known refractive index n ₁ and a refractive index n of the film or coating 3 under conditions of _2. In addition, the reflectance and absorptivity of the beam at a selected wavelength for each film layer or coating interface is known.

The type of the probe beam used for obtaining the thickness value in the first step may be from a laser light source for processing, or may be any wavelength light source, that is, other non-laser light sources.

The power P of the incident beam is transmitted through the transmission medium 2 to the interface of the medium 2 and the film layer or the coating layer 3, and the interface is the interface A, wherein the reflectance of the interface A is R ₁ and the transmitted beam power is (1) R ₁ )P. The distance of the outgoing beam in the film or coating 3 is L until it reaches the interface B of the film layer or the bottom of the coating 3 with other media. The reflectivity of the interface B is R ₂ , and the intensity of the reflected beam is (1). -R ₁ )R ₂ Pexp(-αL), α is the absorption coefficient of the light beam in the film layer or coating 3.

The reflected beam is transmitted through the distance of L to the interface C of the film layer or the top of the coating 3 and the transmission medium 2, wherein the reflectance of the interface C is R ₃ and the energy of the outgoing beam is (1-R ₁ )R ₂ (1- R ₃ ) Pexp(-2αL).

The power ratio r between the outgoing beam and the incident beam;

The relationship between the transmission distance L and the film thickness or coating thickness t is:

The power P of the incident beam and the power P' of the outgoing laser beam can be directly obtained by the power detector, so that the thickness t of the film or coating can be directly calculated.

According to the above working principle analysis, the first method includes the following steps:

In the first step, the power P of the incident beam before entering the film or coating and the power P' of the outgoing beam after being refracted from the film or coating are measured by a power detector;

In the second step, the ratio of the power of the outgoing beam to the power of the incident beam is calculated:

R ₁ is the incident surface reflectivity of the incident beam, R ₂ is the reflection surface reflectance of the film or coating, R ₃ is the exit surface reflectance of the outgoing beam, and L is the transmission distance of the beam within the film or coating;

Where θ is the incident angle of the incident beam, n ₁ is the refractive index of the air medium, and n ₂ is the refractive index of the film or coating.

The second acquisition method selects a dual-wavelength laser for processing, and separately calculates a power ratio of two wavelengths, and the obtained thickness value includes the following steps:

The first step, selection of two-wavelength light sources for obtaining the two-wavelength beam outgoing power to the incident power ratio r, denoted as r ₁ and r _2; absorption coefficient of separate light beams of two wavelengths within the film or coating, respectively, Is α ₁ and α ₂ ; the second step, when the selected double wavelengths are close, the reflectance is similar, so

In this way, the L value can be obtained, and then the thickness value t is calculated;

Referring to FIG. 1, the embodiment further discloses a laser processing apparatus for removing a film or a coating using a laser processing method for removing a film or a coating as described above, comprising: a laser 2 for controlling the laser 2 The industrial computer 1 and the beam expanding device 3, the galvanometer and the lens system 4 are sequentially disposed along the laser emitting direction; wherein the industrial computer is further provided with a power for detecting the light beam emerging from the film or the coating in real time. Detector; 5, the industrial computer calculates the thickness of the film or coating according to the power value obtained by the power detector, and adjusts the laser parameters in real time, so that the laser can quickly and accurately remove the film or coating.

There is also included an X-Y platform 6 for placing the workpiece to be processed, and the X-Y platform 6 drives the workpiece to be moved to complete the removal of the surface film or coating of the workpiece to be processed.

Preferably, the laser 2 is further provided with a power detector for detecting the power of the laser to emit laser light in real time, and transmitting the power value to the industrial computer.

Wherein, the industrial computer 1 adjusts the laser parameters of the laser, including: the output laser power, the laser frequency, the galvanometer scanning speed, the platform moving speed, and the processing times.

More specifically, during the processing, the laser beam is set to have a fixed angle θ with the workpiece to be processed, wherein the power of the incident beam can be measured by a real-time monitoring module in the laser; the output beam power can be monitored in real time by an external power detector. The machining of the entire workpiece or required area can be realized by the movement of the X-Y platform 6 during the machining process.

The laser 2 exiting laser light is transmitted to the galvanometer and lens system 4 through the beam expanding device 3, and the angle θ between the incident laser beam and the substitute workpiece is determined by changing the processing position, and the entire waiting is realized by the movement of the platform during the processing. Processing of workpieces. And a power detecting device is arranged inside the laser, and the laser power emitted by the laser can be displayed in real time on the computer interface of the industrial computer, and then the The relationship is subtracted to calculate the beam power P incident on the workpiece to be processed, and a laser power detecting device is disposed on the laser platform to monitor the power P′ of the transmitted beam through the film layer or the coating in real time, and can be displayed on the computer interface of the industrial computer. .

The thickness value of the film or coating can be obtained by the above two methods. When a two-wavelength laser is selected, the wavelengths of the two lasers λ ₁ ≈ λ ₂ can be measured by measuring the power ratios r ₁ and r ₂ of the two lasers.

Calculate the laser transmission distance L, according to

The thickness t of the film layer can be calculated. If the thickness of the film or coating is not uniform, the film thickness or coating thickness at different locations can be tested according to the position of the incident beam, and then the desired laser processing parameters can be selected according to the measurement results to be more uniform, clean and accurate. Remove the film or coating.

In more detail, the relationship between laser processing parameters and film or coating thickness is established, and appropriate laser processing parameters are selected based on this relationship and the currently measured film or coating thickness.

If the film or coating is thin, the removal can be done at one time, and if it is thick, it can be removed multiple times.

In the case of a thick film or coating, the high-power laser can be used for initial rapid removal, and the feedback signal can be detected in real time until the thickness of the film or coating reaches a preset value, and then the processing parameters are adjusted according to preset values for fine processing. .

The above is only a preferred embodiment of the present invention, and is not intended to limit the embodiments of the present invention. Those skilled in the art can make various modifications or modifications in accordance with the main idea and spirit of the present invention. The scope of protection of the invention shall be determined by the scope of protection claimed in the claims.

Claims

A laser processing method for removing a film or a coating, comprising the steps of:

In the first step, measuring the thickness value of the film or coating;

In the second step, adjusting the parameters of the laser according to the thickness value obtained in the first step;

In the third step, the laser is turned on and the first and second steps are repeated to scan the laser or the surface of the coating until the film or coating is removed.
The laser processing method for removing a film or a coating according to claim 1, wherein before the step of performing the first step, the method further comprises: setting a thickness value as a detection reference in advance, using a uniform laser parameter, and coating or coating the film. The layer is initially removed, and the feedback signal is detected in real time until the thickness of the film or coating reaches a preset value, and then the processing parameters are adjusted according to preset values for fine processing steps.
A laser processing method for removing a film or a coating according to claim 1, wherein the obtaining of the thickness value in the first step comprises the following steps:

In the first step, the power P of the laser before entering the film or coating and the power P' of the outgoing laser after being refracted from the film or coating are measured by a power detector;

In the second step, the power ratio of the power of the outgoing laser to the incident laser is calculated:
R 1 is the incident surface reflectance of the incident laser, R 2 is the reflectance of the reflective surface of the film or coating, R 3 is the exit surface reflectance of the exiting laser, L is the transmission distance of the laser in the film or coating, and α is the laser The absorption coefficient of the beam within the film or coating;

In the third step, the thickness value t is calculated according to the L value obtained in the second step,
Where θ is the incident angle of the laser, n 1 is the refractive index of the air medium, and n 2 is the refractive index of the film or coating.
A laser processing method for removing a film or a coating according to claim 1, wherein Obtaining the thickness value in the first step includes the following steps:

In the first step, a dual-wavelength laser is selected to obtain the power ratio r of the output laser light of the dual-wavelength laser beam and the incident laser, respectively, as r 1 and r 2 respectively ; and the dual-wavelength laser beam is applied to the film or the coating. The internal absorption coefficients are α 1 and α 2 , respectively;

In the second step, when the selected dual wavelengths are close, the reflectivity is similar, so
In this way, the L value can be obtained, and then the thickness value t is calculated;
The laser processing method for removing a film or a coating according to any one of claims 1 to 4, wherein in the step of obtaining a film or coating thickness value, the probe beam used may be derived from processing for processing. The laser source can also be a light source of any wavelength.
A laser processing apparatus for removing a film or a coating using the laser processing method for removing a film or a coating according to any one of claims 1 to 4, comprising: a laser, an industrial computer for controlling the laser And a beam expander, a galvanometer and a lens system arranged in sequence along the laser exit direction; wherein the industrial computer is further provided with a power detector for detecting the laser light from the film or the coating in real time, and the industrial computer is The power value obtained by the power detector calculates the thickness of the film or coating, and adjusts the laser parameters in real time to enable the laser to quickly and accurately remove the film or coating.
A laser processing apparatus for removing a film or a coating according to claim 6, further comprising an XY stage for placing a member to be processed, wherein the XY stage drives the workpiece to be moved to complete a surface film of the workpiece to be processed. Or removal of the coating.
A laser processing apparatus for removing a film or a coating according to claim 6, wherein said laser is further provided with a power detector for detecting the power of the laser to emit laser light in real time, and the power is The value is transferred to the IPC.
A laser processing apparatus for removing a film or coating according to claim 6, wherein The laser processing parameters can be adjusted on the industrial computer, including: laser power output, laser frequency, galvanometer scanning speed, platform moving speed, and processing times.