Method for improving cracks in fiber laser ceramic cutting process

Abstract

The invention discloses a method for improving cracks in an optical fiber laser ceramic cutting process. A method for improving cracks in the fiber laser ceramic cutting process comprises the steps that during laser cutting, through holes are punched in a ceramic plate through a fiber laser cutting machine; the parameters of the optical fiber laser cutting machine for cutting the straight line section are set to be high speed and low frequency, the cutting speed is 8-10 mm / s, and the cutting frequency is 1-2; the parameters of the optical fiber laser cutting machine for cutting the arc section are set to be low speed and multiple times, the cutting speed is 1-3mm / s, and the cutting times is 3-5. According to the method, a traditional step-by-step machining mode of scribing and punching is abandoned, a new technology of full-penetrating micropore array cutting is provided, 100%-penetrating micropore array machining is completed in an etched pure ceramic area through a single optical fiber laser, the whole cutting path is made to be composed of high-density micropores, it is ensured that stress is evenly released, and the problem of cracks in a connection area is thoroughly solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of DCB substrate manufacturing, and relates to a cutting method. BACKGROUND

[0002] Al2O3 ceramic is widely used in the manufacturing of DCB ceramic substrates due to its excellent insulation, high temperature resistance and mechanical strength. In the production of DCB copper clad ceramic substrates, large size substrates (138mm x 190mm) are cut into specific patterns (such as units with circular arcs or chamfers around the periphery) by laser cutting, and then separated into independent small units by external force.

[0003] The original process route uses a double-process split machine to cut, that is, CO2 laser marking (non-penetration) is used to cut the straight line part, and the heat effect forms a molten mark with a depth of about one-third of the thickness on the ceramic surface, and then fiber laser drilling (penetration) is used to cut the circular arc part, and a through hole is processed at the end of the mark to release stress.

[0004] The traditional process uses a step-by-step processing method of "marking first and drilling later", however, this process has the following problems:

[0005] 1. Multi-machine coordination deviation: the marking and drilling need to switch equipment, and the connection position is easy to cause stress concentration due to alignment deviation.

[0006] 2. Crack defects: the marking is not through the ceramic layer, while the drilling is through processing, and the difference between the two heat affected zones causes micro-cracks at the connection during the separation, affecting product yield and reliability. SUMMARY

[0007] The present application provides a method for improving cracks in the process of fiber laser cutting ceramic to solve at least one of the above technical problems.

[0008] A method for improving cracks in the process of fiber laser cutting ceramic, characterized in that, during laser cutting, a through hole is drilled on the ceramic plate by a fiber laser cutting machine;

[0009] The parameters of the fiber laser cutting machine for cutting straight lines are set to high speed and low times, the cutting speed is 8-10 mm / s, and the cutting times are 1-2;

[0010] The parameters of the fiber laser cutting machine for cutting circular arcs are set to low speed and multiple times, the cutting speed is 1-3 mm / s, and the cutting times are 3-5.

[0011] This invention abandons the traditional step-by-step processing method of "scribing + drilling" and proposes a new process of "full-through micro-hole array cutting". In the etched pure ceramic area, a single fiber laser is used to complete the 100% through micro-hole array processing, so that the entire cutting path is composed of high-density micro-holes, ensuring uniform stress release and completely eliminating the problem of cracks in the connection area.

[0012] This invention optimizes the laser cutting process by using a novel single-fiber laser full-penetration drilling method, eliminating the joint cracks in traditional step-by-step processing and improving the yield of DCB ceramic substrates.

[0013] More preferably, the laser mode of the fiber laser cutting machine is pulse mode.

[0014] In pulsed mode, the laser can generate millisecond-level pulses with a duty cycle of 10%, and can output peak power tens of times higher than the average power, with high beam quality and small divergence angle.

[0015] According to the energy control equation:

[0016] E pulse =P avg *τ (τ: pulse width, P) avg (Average power)

[0017] When E pulse >E th At a certain threshold (ceramic vaporization threshold), the ceramic layers vaporize layer by layer to form through-holes; therefore, in pulse mode, the ceramic layers are more likely to vaporize and form through-holes. A gradually changing temperature gradient is generated under a wider pulse width, avoiding microcracks in the pore walls caused by rapid heating and cooling.

[0018] More preferably, the laser power of the laser cutting machine is 40% of the rated power;

[0019] The laser cutting machine has a frequency of 200Hz;

[0020] The pulse width of the laser cutting machine is 500–600 μs.

[0021] More preferably, the fiber laser cutting machine forms a cutting path on the ceramic plate. The cutting path includes an outgoing line located outside the closed contour, which moves from the outgoing line to the starting position of the closed contour. The ending position of the cutting path is connected to the starting position of the closed contour.

[0022] More preferably, the closed contour is a rounded rectangle, and the leader line is connected to the center of the long side of the rounded rectangle.

[0023] More preferably, the length of the lead wire is 0.5 mm.

[0024] Further preferably, the galvanometer system of the fiber laser cutting machine drives the laser to punch point by point along the preset pattern, and the aperture of the cutting head is 1 mm.

[0025] Further preferably, before the fiber laser cutting machine cuts;

[0026] First, the copper-clad DCB substrate is selectively etched according to the drawing, and the copper layer in the cutting path area is completely removed to expose the ceramic plate below, and the laser only acts on the ceramic;

[0027] Then, the etched substrate is placed on a vacuum adsorption platform, the adsorption system is started, the vacuum degree is ≥0.08 MPa, and the substrate is ensured to be zero offset; the reference point is aligned through the CCD vision system, the precision is ±5 μm, and the cutting pattern coordinates are loaded.

[0028] Further preferably, the thickness of the ceramic plate at the copper layer etching area is 0.3-1.0 mm.

[0029] Further preferably, after the fiber laser cutting machine cuts, the back of the ceramic plate is lightly scraped with a porcelain sheet, and the small pieces of the micro-porous connected area automatically fall off.

[0030] A method for improving cracks in the process of cutting ceramic by a fiber laser, characterized in that it comprises the following steps:

[0031] Step one, pattern etching;

[0032] First, the copper-clad DCB substrate is selectively etched according to the drawing, and the copper layer in the cutting path area is completely removed to expose the ceramic plate below, and the laser only acts on the ceramic;

[0033] Step two, the etched copper-clad DCB substrate is placed on a vacuum adsorption platform, the adsorption system is started, the vacuum degree is ≥0.08 MPa, and the substrate is ensured to be zero offset; the reference point is aligned through the CCD vision system;

[0034] Step three, laser cutting is performed by a fiber laser cutting machine;

[0035] The parameters of the fiber laser cutting machine in cutting a straight line segment are set to high speed and low times, the cutting speed is 8-10 mm / s, and the cutting times are 1-2;

[0036] The parameters of the fiber laser cutting machine in cutting a circular arc segment are set to low speed and multiple times, the cutting speed is 1-3 mm / s, and the cutting times are 3-5;

[0037] The laser mode of the fiber laser cutting machine is pulse mode;

[0038] The laser power of the laser cutting machine is 40% of the rated power;

[0039] The frequency of the laser cutting machine is 200 Hz;

[0040] The pulse width of the laser cutting machine is 500-600 μs.

[0041] Beneficial effects:

[0042] Process mode innovation: single-fiber laser full-punching process is adopted to eliminate the multi-machine switching and thermal stress mismatching problem of traditional "CO2 scribing + fiber punching", so that the crack defect rate is significantly reduced, and the micro-crack problem at the circular corner is solved.

[0043] Energy control optimization: through the "low heat input through-punching" technology, the laser parameters are accurately regulated so that the laser only penetrates the ceramic layer, reduces the heat affected zone, and improves the cutting precision.

[0044] Yield improvement: there is no micro-crack at the edge of the broken piece, and the product qualification rate is improved from 85% of the traditional process to more than 99%.

[0045] Efficiency optimization: this process can be completed on a single laser device without switching machines, reducing the alignment error, improving the production efficiency, and reducing the equipment cost.

[0046] Wide adaptability: suitable for Al2O3, ZrO2 and other ceramic substrates, especially suitable for high-precision DCB module packaging. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a schematic diagram of the cutting path of embodiment 1;

[0048] Figure 2 is a cross-sectional view of the cutting of the fiber laser cutting machine of the present application in embodiment 1;

[0049] Figure 3 is a cross-sectional view of the cutting of the traditional process. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0051] Referring to Figure 1 and Figure 2 , in embodiment 1, a method for improving cracks in the process of fiber laser cutting ceramic, a through hole is punched on the ceramic plate by a fiber laser cutting machine during laser cutting;

[0052] The parameters of the fiber laser cutting machine in cutting straight line segments are set to high speed and low times, and the cutting speed is 8-10 mm / s, and the cutting times are 1-2;

[0053] The parameters of the fiber laser cutting machine in cutting circular arc segments are set to low speed and multiple times, and the cutting speed is 1-3 mm / s, and the cutting times are 3-5.

[0054] The application discards the traditional step-by-step processing mode of "marking line + punching", and proposes a new technology of "full-penetration micro-hole array cutting", which uses a single fiber laser to complete 100% penetration micro-hole array processing in the pure ceramic area after etching, so that the entire cutting path is composed of high-density micro-holes, ensuring uniform stress release and completely eliminating the crack problem in the connection area.

[0055] The laser mode of the fiber laser cutting machine is pulse mode. In pulse mode, the laser can generate a millisecond pulse with a duty cycle of 10%, can output a peak power higher than the average power by dozens of times, has high beam quality and small divergence angle.

[0056] According to the energy control equation:

[0057] E pulse =P avg *τ(τ:pulse width, P avg : average power)

[0058] When E pulse >E th (ceramic vaporization threshold), the ceramic layer is vaporized to form a through hole; therefore, in pulse mode, the ceramic layer is more easily vaporized to form a through hole. Under the condition of a wider pulse width, a slow temperature gradient is generated, avoiding the micro-cracks of the hole wall caused by rapid cooling and heating.

[0059] The laser power of the laser cutting machine is 40% of the rated power;

[0060] The frequency of the laser cutting machine is 200Hz;

[0061] The pulse width of the laser cutting machine is 500-600us.

[0062] Referring to Figure 1 , the fiber laser cutting machine forms a cutting path on the ceramic plate, the cutting path includes a lead-out line 1 located outside the closed contour, moves from the lead-out line 1 to the starting point position of the closed contour 2, and the end point of the cutting path is connected with the starting point position of the closed contour.

[0063] The closed contour 2 is a round rectangle, and the lead-out line is connected with the center of the long side of the round rectangle.

[0064] The length of the lead-out line is 0.5mm.

[0065] The galvanometer system of the fiber laser cutting machine drives the laser to punch along the preset pattern point by point, and the aperture of the cutting head is 1 mm.

[0066] Before cutting by the fiber laser cutting machine;

[0067] First, according to the drawing, the copper-clad DCB substrate is selectively etched, and the copper layer in the cutting path area is completely removed to expose the ceramic plate below, and the laser only acts on the ceramic;

[0068] Then, the etched substrate is placed on the vacuum adsorption platform, the adsorption system is started, the vacuum degree is ≥0.08 MPa, and the substrate is zero offset; the reference point is aligned through the CCD vision system, the precision is ±5μm, and the cutting pattern coordinates are loaded.

[0069] The thickness of the ceramic plate in the copper layer etching area is 0.3-1.0 mm.

[0070] After cutting by the fiber laser cutting machine, the back of the ceramic plate is lightly scraped with a porcelain sheet, and the small pieces of the micro-porous connected area automatically fall off. The porcelain powder on the back is scraped off with a porcelain sheet, and the small pieces will fall off.

[0071] A method for improving cracks in the process of cutting ceramic by fiber laser, characterized in that it comprises the following steps:

[0072] Step one, pattern etching;

[0073] First, according to the drawing, the copper-clad DCB substrate is selectively etched, and the copper layer in the cutting path area is completely removed to expose the ceramic plate below, and the laser only acts on the ceramic; the thickness of the ceramic plate in the copper layer etching area is 0.3-1.0 mm.

[0074] Step two, place the etched copper-clad DCB substrate on the vacuum adsorption platform, start the adsorption system, the vacuum degree is ≥0.08 MPa, and the substrate is zero offset; the reference point is aligned through the CCD vision system;

[0075] Step three, laser cutting by the fiber laser cutting machine;

[0076] The parameters of the fiber laser cutting machine in cutting straight line segment are set to high speed and low times, the cutting speed is 8-10 mm / s, and the cutting times are 1-2;

[0077] The parameters of the fiber laser cutting machine in cutting circular arc segment are set to low speed and multiple times, the cutting speed is 1-3 mm / s, and the cutting times are 3-5;

[0078] The laser mode of the fiber laser cutting machine is pulse mode;

[0079] The laser power of the laser cutting machine is 40% of the rated power;

[0080] The frequency of the laser cutting machine is 200Hz;

[0081] The pulse width of the laser cutting machine is 500-600us.

[0082] The parameters of the present application are as follows:

[0083]

[0084] Referring to Figure 2 is a cross-sectional view of the perforation of the present application.

[0085] The parameters of the conventional "fiber perforation+CO2 scribing" double process are as follows:

[0086]

[0087] Referring to Figure 3 is a cross-sectional view of the conventional process after cutting, the left end is the perforation, and the right end is the scribing.

[0088] It is apparent for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as illustrative and not restrictive, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and range of equivalents of the claims. Any reference signs in the claims should not be considered as limiting the claims to which they belong.

[0089] Furthermore, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A method of improving cracks in a process of fiber laser cutting ceramic, characterized by, When laser cutting, a through hole is punched on the ceramic plate by the fiber laser cutting machine; The parameters of the fiber laser cutting machine for cutting straight line segments are set as high speed and low times, the cutting speed is 8-10 mm / s, and the cutting times are 1-2; The parameters of the fiber laser cutting machine for cutting circular arc segments are set as low speed and multiple times, the cutting speed is 1-3 mm / s, and the cutting times are 3-5.

2. The method of claim 1, wherein: The laser mode of the fiber laser cutting machine is pulse mode.

3. The method for improving crack formation during fiber laser cutting of ceramics according to claim 1, characterized in that: The laser power of the laser cutting machine is 40% of the rated power; The frequency of the laser cutting machine is 200 Hz; The pulse width of the laser cutting machine is 500-600 μs.

4. The method of claim 1, wherein: The fiber laser cutting machine forms a cutting path on the ceramic plate, the cutting path includes a lead-out line outside the closed contour, moves from the lead-out line to the starting position of the closed contour, and the end point of the cutting path is connected to the starting position of the closed contour.

5. The method of claim 1, wherein: The closed contour is a rounded rectangle, and the lead-out line is connected to the center of the long side of the rounded rectangle.

6. The method of claim 1, wherein: The length of the lead-out line is 0.5 mm.

7. The method of claim 1, wherein: The galvanometer system of the fiber laser cutting machine drives the laser to punch point by point along the preset pattern, and the cutting head aperture is 1 mm.

8. The method of claim 1, wherein: Before the fiber laser cutting machine cuts; First, according to the drawing, the DCB copper-clad substrate is selectively etched, the copper layer in the cutting path area is completely removed, the ceramic plate below is exposed, and it is ensured that the laser only acts on the ceramic; Then, the etched substrate is placed on the vacuum adsorption platform, the adsorption system is started, the vacuum degree is ≥0.08 MPa, and it is ensured that the substrate is zero offset; the reference point is aligned through the CCD vision system, the accuracy is ±5 μm, and the cutting pattern coordinates are loaded.

9. The method for improving crack formation during fiber laser cutting of ceramics according to claim 1, characterized in that: After the fiber laser cutting machine cuts, the ceramic plate back is lightly scraped with a porcelain sheet, and the small pieces in the micropore communication area automatically fall off.

10. A method of improving cracks in a process of fiber laser cutting ceramic, characterized by, It includes the following steps: Step one, graphic etching; First, according to the drawing, the DCB copper-clad substrate is selectively etched, the copper layer in the cutting path area is completely removed, the ceramic plate below is exposed, and the thickness of the ceramic plate at the copper layer etching area is 0.3-1.0 mm, which ensures that the laser only acts on the ceramic; Step two, place the etched DCB copper-clad substrate on the vacuum adsorption platform, start the adsorption system, the vacuum degree is ≥0.08 MPa, and it is ensured that the substrate is zero offset; the reference point is aligned through the CCD vision system; Step three, laser cutting by the fiber laser cutting machine; The parameters of the fiber laser cutting machine for cutting straight line segments are set as high speed and low times, the cutting speed is 8-10 mm / s, and the cutting times are 1-2; The parameters of the fiber laser cutting machine for cutting circular arc segments are set as low speed and multiple times, the cutting speed is 1-3 mm / s, and the cutting times are 3-5; The laser mode of the fiber laser cutting machine is pulse mode. The laser power of the laser cutting machine is 40% of the rated power; The frequency of the laser cutting machine is 200 Hz; The pulse width of the laser cutting machine is 500-600 μs.

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