Optimization processing method for roughness of side wall of glass blind groove

Abstract

The invention provides an optimization processing method for roughness of a side wall of a glass blind groove. The optimization processing method comprises the following steps: S1, carrying out first-time laser-induced modification on a glass substrate according to a track I by adopting first laser; s2, second laser is adopted for conducting second-time laser-induced modification on the modified glass substrate according to a second track, and the second track is located on the outer side of the first track, a plurality of second ablation points formed by modifying the second laser on the track II on the glass substrate and a plurality of first ablation points formed by modifying the first laser on the track I on the glass substrate are arranged in a staggered manner; and S3, carrying out chemical corrosion treatment on the glass substrate subjected to laser-induced modification twice. According to the method, on the basis of the first laser-induced modification, the modified glass substrate is subjected to the second laser-induced modification by using the second laser, so that the roughness Ra of the side wall of the glass blind groove can reach 100 nm or below, the glass micropore forming quality is improved, and the signal transmission performance of the glass substrate and the CPO packaging stability are also improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of glass-based optoelectronic co-packaging, and particularly relates to a glass blind slot sidewall roughness optimization processing method. BACKGROUND

[0002] Optoelectronic co-packaging (CPO) is a new type of optoelectronic integration technology, which is based on advanced packaging technology to heterogeneously integrate optical transceiver modules and application-specific integrated circuit (ASIC) chips in a package to form a microsystem with certain functions. Optoelectronic co-packaging technology further shortens the electrical interconnection length between the optical signal input and the operation unit, improves the interconnection density between the optical module and the ASIC chip, and realizes lower power consumption, which is an important technical approach to solving the problem of high-speed transmission of massive data in future large data processing.

[0003] Glass material has high light transmittance, low loss electrical interconnection characteristics and excellent dimensional stability, and is very suitable as a CPO adapter plate. Cavities and micro-vias need to be formed on the glass adapter plate to form 2.5D or 3D optical signal transmission.

[0004] In glass micro-hole such as blind slot, micro-via technology, first, a modified region is formed on the glass substrate by pulses generated by a laser, and then removed by chemical etching. Since the etching rate of the modified region is much higher than that of the unmodified region, a micro-hole structure is finally generated along the modified region. Due to the non-uniformity in the chemical etching process, irregular pit structures often appear on the sidewall of the micro-hole, resulting in a high sidewall roughness, usually with a sidewall roughness Ra of 1-2 microns.

[0005] The sidewall roughness of the micro-hole plays a crucial role in the reliability and integrity of signal transmission, especially at high frequencies. As the sidewall roughness increases, the adverse effects of parasitic effects become more pronounced. High roughness sidewalls increase scattering and reflection effects during signal transmission, causing energy loss and reducing transmission efficiency, and may also cause electromagnetic interference. Secondly, the high roughness of the sidewall makes the metallization and filling process more complex, affecting the bonding strength of the glass micro-hole and the metal material, thereby reducing the overall reliability of the structure. In addition, the non-uniformity of the sidewall roughness may weaken the mechanical properties of the device under the action of thermal cycling or mechanical stress, and even cause the device to crack or delaminate. SUMMARY

[0006] The purpose of the present application is to provide a glass blind slot sidewall roughness optimization processing method, which can at least solve some of the defects in the prior art.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0008] A method for optimizing the roughness of a glass blind slot sidewall, comprising the following steps:

[0009] S1, using a first laser to perform a first laser-induced modification on a glass substrate according to a predetermined blind slot pattern track one;

[0010] S2, using a second laser to perform a second laser-induced modification on the glass substrate modified in step S1 according to a track two, wherein the track two is located outside the track one, and a plurality of second ablation points formed on the glass substrate by the second laser on the track two are arranged in a staggered manner with a plurality of first ablation points formed on the glass substrate by the first laser on the track one;

[0011] S3, performing a chemical etching treatment on the glass substrate which has been twice laser-induced modified in steps S1 and S2.

[0012] Further, the diameter of the second ablation point is smaller than the diameter of the first ablation point.

[0013] Further, the second ablation point and the two first ablation points adjacent thereto are tangent.

[0014] Further, when the track one is a straight line, the track two is located on both sides of the track one; when the track one is a closed pattern, the track two is located outside the track one.

[0015] Further, the first laser and the second laser are both Bessel beams with a certain focal depth length formed by an ultrafast laser through a beam shaping module.

[0016] Further, the second laser and the first laser use the same Bessel beam source, and the laser single pulse energy of the second laser is smaller than that of the first laser.

[0017] Further, the Bessel beam focusing spot diameter of the second laser is smaller than that of the first laser, and the focal depth of the Bessel beam of the second laser is smaller than that of the first laser.

[0018] Further, the depth of the Bessel beams of the first laser and the second laser in the modification of the glass substrate is greater than the required blind slot depth by 30-50 μm.

[0019] Further, in step S3, the chemical etching treatment is performed using an alkaline solution, and the alkaline etching conditions are as follows: the alkaline solution is sodium hydroxide or potassium hydroxide solution, the mass concentration of the alkaline solution is 20-50%, the alkaline solution etching temperature is 80-120℃, and the etching time is 10-20h.

[0020] Further, in the step S3, the chemical etching treatment is performed by using an acid solution, and the acid etching conditions are as follows: the acid solution is prepared by mixing hydrofluoric acid and ammonium fluoride according to a ratio of 1:1-5:1, the acid solution etching temperature is 20-25 DEG C, and the etching time is 6-12 hours.

[0021] Compared with the prior art, the present application has the following advantages:

[0022] The present application eliminates the convex structure between the adjacent first ablation points in the first laser-induced modification by using the second laser-induced modification of the second laser on the basis of the first laser-induced modification, so that a uniform and continuous modified surface is formed on the modified side, thereby uniformly etching to form a smooth sidewall in the chemical etching process. The sidewall roughness Ra of the glass blind groove obtained by this method can be less than 100 nm, which not only significantly improves the pore forming quality of the glass micro-pore, but also improves the signal transmission performance of the glass substrate and the stability of the CPO packaging.

[0023] The present application will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a schematic view of the relative positions of the first laser irradiation track one and the second laser irradiation track two in the embodiment of the present application;

[0025] Figure 2 is a microscopic picture of the blind groove sidewall obtained by only the first laser-induced modification once and the first laser and the second laser-induced modification twice in the embodiment of the present application.

[0026] Legend of reference signs: 1, first ablation point; 2, second ablation point. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0029] In the description of the present application, it should be noted that unless specifically defined and limited otherwise, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or interference connection or integral connection; for those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0030] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features; in the description of the present application, unless otherwise stated, the meaning of "multiple" is two or more.

[0031] As shown in Figure 1 The embodiment of the present application provides a glass blind groove side wall roughness optimization processing method, which comprises the following steps:

[0032] S1, a first laser is used to perform first laser-induced modification on a glass substrate according to a first track of a predetermined blind groove pattern.

[0033] S2, a second laser is used to perform second laser-induced modification on the glass substrate modified in step S1 according to a second track, wherein the second track is located outside the first track, and a plurality of second ablation points 2 formed on the glass substrate by the second laser on the second track are arranged in a staggered manner with a plurality of first ablation points 1 formed on the glass substrate by the first laser on the first track.

[0034] S3, the glass substrate subjected to the twice laser-induced modification in steps S1 and S2 is subjected to chemical etching treatment.

[0035] In the embodiment, the first laser spot irradiates the glass substrate to form a small hole point (i.e. the first ablation point 1) with a certain depth from top to bottom, and a plurality of the first ablation points 1 constitute the first track. Since the circular spot irradiates the glass substrate, a convex structure is formed between two adjacent first ablation points 1, which makes the side surface of the modified area discontinuous. On this basis, the second laser is designed to perform second laser-induced modification, so that the second ablation points 2 formed by the second laser spot irradiating the glass substrate act on the convex structure between the adjacent first ablation points 1 in the first laser-induced modification, thereby eliminating the convex structure and forming a uniform and continuous modified surface on the modified side surface, and then uniformly etching to form a smooth side wall in the chemical etching process.

[0036] The technical scheme is optimized. In order to ensure the processing quality of the glass blind groove, the glass substrate is pretreated before laser-induced modification to ensure the cleanliness of the glass substrate. Specifically, the glass substrate can be cleaned first to remove surface impurities, dust, oil stains and the like, and then dried. Further, after the chemical etching treatment of the glass substrate, the etched glass substrate is placed in a deionized water solution for ultrasonic cleaning to remove the etching solution on the surface of the glass substrate, i.e. the interior of the blind groove, and then dried in an oven.

[0037] For the present embodiment, the trajectories (i.e. trajectory one and trajectory two) of the first laser and the second laser irradiating the glass substrate are determined by the blind groove pattern to be processed, as shown in the figure. The trajectory one can be a straight line or a closed pattern such as a rectangle, a circle, etc. When the trajectory one is a straight line, the trajectory two is designed to be located on both sides of the trajectory one. When the trajectory one is a closed pattern, the trajectory two is located outside the trajectory one. Figure 1

[0038] The optimized embodiment is designed to form a second ablation point 2 on the glass substrate by the second laser, and the diameter of the second ablation point 2 is smaller than the diameter of the first ablation point 1 formed on the glass substrate by the first laser. In this way, the ablation points of the trajectory one are larger and arranged on the inner side, and the ablation points of the trajectory two are smaller and arranged on the outer side of the trajectory one. When the ablation points of the trajectory one and the trajectory two are arranged in a staggered manner, the small ablation points of the trajectory two are located between the two large ablation points of the trajectory one, which can further eliminate the convex structure between the two first ablation points 1 of the trajectory one, and at the same time, the ablation area of the outer edge of the first ablation point 1 is not expanded too much.

[0039] Further optimization is designed to make the second ablation point 2 and the two first ablation points 1 adjacent thereto tangent. In this way, the second ablation point 2 can cover the convex structure area between the two first ablation points 1 to the maximum extent, thereby eliminating the convex structure between the two first ablation points 1 to the maximum extent, so as to form a uniform and continuous modification surface on the modification side.

[0040] ​As an optimized implementation, the first laser and the second laser adopt Bessel light focusing processing, and the Bessel beam has a large focal depth length. For processing a deep blind groove structure, the Bessel air focal depth of the first laser and the second laser can process the required blind groove depth at one time, without the need for repeated processing multiple times, thereby improving the processing efficiency. Specifically, the first laser and the second laser are both Bessel beams with a certain focal depth length formed by an ultrafast laser through a beam shaping module; wherein the ultrafast laser can be but is not limited to a picosecond laser, a femtosecond laser, etc.; the Bessel air focal depth length of the first laser and the second laser is smaller than the thickness of the glass substrate; the Bessel beam generates high peak power and high peak power density laser, which is focused inside the glass substrate, instantaneously vaporizes the materials in the region to form a vaporization zone, rapidly diffuses to the upper and lower surfaces to form a crack point (i.e. the first ablation point 1 or the second ablation point 2), and the modified cross section is composed of numerous fine crack points, thereby realizing laser-induced modification of the glass substrate. The fine crack points and the ablation area at the edge of the crack points formed after the Bessel laser irradiates the glass substrate have a much higher etching rate than the unirradiated area of the glass substrate in the chemical etching liquid, thereby forming a blind groove structure with a modified pattern.

[0041] The depth of the modified area of the first laser and the second laser on the glass substrate is determined by the relative height of the Bessel beam and the surface of the glass substrate and the required groove depth, and the depth of the modified area of the first laser and the second laser in the glass substrate is optimized to be 30-50 μm greater than the required blind groove depth.

[0042] In order to realize the condition that the diameter of the second ablation point 2 formed by the second laser on the glass substrate is smaller than the diameter of the first ablation point 1 formed by the first laser on the glass substrate, in some embodiments, the second laser and the first laser can be designed to adopt the same Bessel beam source, and at this time, the laser single pulse energy of the second laser is smaller than the laser single pulse energy of the first laser by adjusting the laser single pulse energy. In other embodiments, the second laser and the first laser can also come from the same laser, but pass through different beam shaping modules, so that the Bessel beam focusing spot diameter of the second laser is smaller than the Bessel beam focusing spot diameter of the first laser, and the focal depth of the Bessel beam of the second laser is smaller than the focal depth of the Bessel beam of the first laser.

[0043] As a specific embodiment, in the step S3, the chemical etching treatment can be performed by using an alkaline solution, and the alkaline etching conditions are as follows: the alkaline solution is sodium hydroxide or potassium hydroxide solution, the mass concentration of the alkaline solution is 20-55%, the alkaline solution etching temperature is 80-120℃, and the etching time is 10-20h. In other embodiments, in the step S3, the chemical etching treatment can also be performed by using an acid solution, and the acid etching conditions are as follows: the acid solution is prepared by mixing hydrofluoric acid and ammonium fluoride according to a ratio of 1:1-5:1, the acid solution etching temperature is 20-25℃, and the etching time is 6-12h.

[0044] The specific process and effects of the method for optimizing the roughness of the side wall of the glass blind groove are described below through a specific embodiment and comparative examples.

[0045] Embodiment: The embodiment provides a method for optimizing the roughness of the side wall of a glass blind groove, and the specific process is as follows:

[0046] S1: A 0.5mm thick Corning BF33 glass substrate is ultrasonically cleaned in a mixed solution of alcohol and acetone to remove impurities, dust, and oil stains on the surface, and is dried in a drying box.

[0047] S2: A first laser is a 1035nm infrared femtosecond laser, which is expanded to a 8mm spot diameter, enters a beam shaper to form a 0.3mm Bessel beam with an air focal depth, the focal depth of the Bessel beam is less than the thickness of the glass substrate, the laser single pulse energy is 80μJ, the relative height of the first laser and the glass substrate is adjusted, the first laser is used to modify the glass substrate, when the modification depth is the preset 100μm, the relative height of the first laser and the glass substrate is fixed, the first laser is used to irradiate the glass substrate, and a laser irradiation track is formed as track one, and the overall modification depth is the preset 100μm.

[0048] S3: The second laser is the same as the first laser, and both are 0.3mm Bessel beams, the laser single pulse energy used by the second laser is 40μJ, the glass substrate in the modification region is irradiated by the second laser to form track two, and the ablation point positions of track one and track two are controlled by PSO, and the point spacing is set to 1μm.

[0049] S4: The glass substrate after the two modifications is chemically etched in a 55% mass concentration KOH solution at a temperature of 80℃ for 16h.

[0050] S5: The glass substrate after etching is cleaned in a deionized water solution to remove the alkaline etching liquid on the surface of the glass and in the blind groove, and is dried in an oven.

[0051] The comparative example is basically the same as the above-mentioned example, except that only the first laser-induced modification process is used in the comparative example, and the second laser-induced modification process is not used.

[0052] The micrographs of the blind slot structures obtained in the above-mentioned comparative example and example are shown in Figure 2 (a) and Figure 2 (b), respectively. As can be seen from Figure 2 the micrographs, the side wall of the blind slot obtained without the second laser-induced modification process is uneven, while the side wall of the blind slot obtained with the second laser-induced modification process is smooth. It is detected and calculated that the width of the blind slot obtained in the above-mentioned example is 80 μm, the depth of the blind slot is 70 μm, and the roughness of the side wall of the blind slot is 20 nm.

[0053] The above-mentioned examples are only illustrative of the present application, and do not constitute a limitation on the protection scope of the present application. Any design identical or similar to the present application falls within the protection scope of the present application.

Claims

1. A method for optimizing the roughness of the sidewall of a glass blind groove, characterized in that, Includes the following steps: S1. The first laser is used to perform the first laser-induced modification on the glass substrate according to the trajectory of the predetermined blind groove pattern; S2. A second laser is used to perform a second laser-induced modification on the glass substrate that has been modified in step S1 according to trajectory two. The trajectory two is located outside the trajectory one, and the multiple second ablation points formed by the second laser on the glass substrate on the trajectory two are staggered with the multiple first ablation points formed by the first laser on the glass substrate on the trajectory one. S3. The glass substrate that has undergone laser-induced modification in steps S1 and S2 is subjected to chemical etching treatment.

2. The method for optimizing the roughness of the sidewall of a glass blind groove as described in claim 1, characterized in that, The diameter of the second ablation point is smaller than the diameter of the first ablation point.

3. The method for optimizing the roughness of the sidewall of a glass blind groove as described in claim 2, characterized in that, The second ablation point is tangent to the two adjacent first ablation points.

4. The method for optimizing the roughness of the sidewall of a glass blind groove as described in claim 1, characterized in that, When trajectory one is a straight line, trajectory two is located on both sides of trajectory one; when trajectory one is a closed figure, trajectory two is located on the outside of trajectory one.

5. The method for optimizing the roughness of the sidewall of a glass blind groove as described in any one of claims 1-4, characterized in that, Both the first and second lasers are Bessel beams with a certain depth of focus formed by ultrafast lasers through a beam shaping module.

6. The method for optimizing the roughness of the sidewall of a glass blind groove as described in claim 5, characterized in that, The second laser and the first laser use the same Bessel beam source, and the laser single pulse energy of the second laser is less than that of the first laser.

7. The method for optimizing the roughness of the sidewall of a glass blind groove as described in claim 5, characterized in that, The diameter of the focused Bessel beam of the second laser is smaller than that of the focused Bessel beam of the first laser, and the depth of focus of the Bessel beam of the second laser is smaller than that of the Bessel beam of the first laser.

8. The method for optimizing the roughness of the sidewall of a glass blind groove as described in claim 5, characterized in that, The Bessel beams of the first and second lasers modify the glass substrate to a depth greater than the required blind groove depth by 30-50 μm.

9. The method for optimizing the roughness of the sidewall of a glass blind groove as described in claim 1, characterized in that, In step S3, the chemical corrosion treatment is carried out using an alkaline solution. The alkaline corrosion conditions are as follows: the alkaline solution is a sodium hydroxide or potassium hydroxide solution, the mass concentration of the alkaline solution is 20-50%, the corrosion temperature of the alkaline solution is 80-120℃, and the corrosion time is 10-20h.

10. The method for optimizing the roughness of the sidewall of a glass blind groove as described in claim 1, characterized in that, In step S3, the chemical corrosion treatment is carried out using an acidic solution. The acidic corrosion conditions are as follows: the acidic solution is prepared by mixing hydrofluoric acid and ammonium fluoride in a ratio of 1:1 to 5:1, the acidic solution corrosion temperature is 20-25℃, and the corrosion time is 6-12h.

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