Preparation method of metalized vertical glass through hole

Abstract

The invention discloses a preparation method of a metalized vertical glass through hole. The preparation method comprises the following steps: modifying a target area of a glass substrate by adopting a laser irradiation method to form a denatured area; forming a first metal layer on the glass substrate in a sputtering manner; ablating the first metal layer corresponding to the denatured region by adopting an ultraviolet radiation method so as to expose the denatured region; etching the denaturation region by using a corrosive liquid to form a first blind hole; cleaning and drying the glass substrate; forming a second metal layer on the glass substrate in a sputtering manner; ablating the second metal layer at the bottom of the first blind hole by adopting an ultraviolet radiation method; etching the first blind hole by using a corrosive liquid to form a second blind hole; cleaning and drying the glass substrate; and repeating the steps (6)-(9) to obtain the metalized vertical glass through hole. According to the preparation method, the glass through hole with high depth-diameter ratio and good perpendicularity can be prepared, and meanwhile, the metal layer can be stably and uniformly attached to the inner wall of the glass through hole.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor packaging, and in particular relates to a method for preparing a metallized vertical through-glass via. Background Art

[0002] Through-Glass Via (TGV) technology and its hole wall metallization are key technologies that have developed rapidly in the field of advanced packaging in recent years. This technology is mainly used on glass substrates. It achieves electrical connection by making small and precise through holes in glass materials and metallizing the inner walls of these holes. Glass substrates are composed of circuits with glass surfaces and metal through holes perpendicular to the surface. They are one of the core components in advanced packaging and semiconductor stacking technologies, and are highly praised by the industry for their excellent electrical performance, thermal stability and mechanical strength.

[0003] As electronic devices develop towards smaller size and higher integration, the market has put forward higher requirements for TGV technology, especially in terms of the verticality of through-holes and the uniform coverage of metal layers. At present, most TGV manufacturing processes use a single laser etching through-hole. Although this method can quickly form through-holes, the so-called "waist" phenomenon often occurs in the middle of the hole, that is, the aperture narrows in the middle. This structural irregularity not only affects the electrical performance of the through-hole, but may also cause uneven electroplating or insufficient adhesion of the metal layer in the subsequent metallization process, thereby affecting the reliability and performance of the final product.

[0004] Therefore, there is an urgent need for a method for preparing a metallized vertical through-glass via to solve the deficiencies of the prior art. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a method for preparing a metallized vertical glass via, which can produce a glass via with a high aspect ratio and good verticality, while ensuring that the metal layer can be stably and evenly attached to the inner wall of the glass via.

[0006] To achieve the above objectives, the present invention provides a method for preparing a metallized vertical through-glass via, the steps comprising:

[0007] (1) modifying a target area of ​​a glass substrate by laser irradiation to form a denatured area;

[0008] (2) forming a first metal layer on the glass substrate by sputtering;

[0009] (3) ablating the first metal layer corresponding to the modified area by ultraviolet irradiation to expose the modified area;

[0010] (4) etching the denatured area with a corrosive solution to form a first blind hole;

[0011] (5) Cleaning and drying the glass substrate;

[0012] (6) forming a second metal layer on the glass substrate by sputtering;

[0013] (7) ablating the second metal layer at the bottom of the first blind hole by ultraviolet irradiation;

[0014] (8) etching the first blind hole using a corrosive solution to form a second blind hole;

[0015] (9) Cleaning and drying the glass substrate;

[0016] (10) Repeat steps (6) to (9) until all the glass in the modified area is removed to obtain a metallized vertical glass through hole.

[0017] Compared with the prior art, the present invention uses laser modification to accurately control the shape and depth of the modified area, so that the subsequent etching liquid can evenly etch the glass in the modified area, ensuring the verticality of the through hole; at the same time, a metal layer is formed by sputtering, and the side wall metal layer is retained by ablating the bottom metal layer, so that the side wall of the blind hole is effectively protected during the etching of the bottom glass and will not be affected by the etching liquid, which ensures the integrity of the side wall of the through hole and further ensures the verticality of the through hole; at the same time, by repeating steps (6) to (9), that is, by repeatedly cycling the steps of metal deposition, ultraviolet ablation, and etching with etching liquid, the through hole can be gradually deepened, and the side wall of the blind hole is effectively protected in each cycle, ensuring the uniformity and verticality of each etching, and finally forming a vertical through hole with a high aspect ratio and consistent diameters of the upper and lower parts. In addition, laser irradiation of the target area causes tiny unevenness on the glass surface, which increases the contact area between the first metal layer and the glass surface and improves the adhesion of the metal. At the same time, the corrosive liquid not only physically changes the roughness of the glass surface during the etching of the denatured area, but also chemically activates the surface. The appropriate rough surface provides more physical adsorption sites, making it easier for the metal to stably adhere to the hole wall, and the enhanced chemical activity of the rough surface can further improve the adhesion between the metal layer and the hole wall; at the same time, the present application adopts sputtering to form a metal layer, which can achieve uniform coverage and ensure the uniformity and density of the metal layer on the side wall of the blind hole. Therefore, the preparation method of the present invention can produce a glass through hole with a high aspect ratio and good verticality, which can greatly improve the current loss problem; at the same time, it ensures that the metal layer can stably and evenly adhere to the inner wall of the glass through hole, which provides a good seed layer for subsequent electroplating.

[0018] Furthermore, step (1) of the present invention further includes first ultrasonically cleaning and drying the glass substrate in a cleaning solution. The cleaning solution includes, but is not limited to, water and alkali solution. Specifically, ultrasonic cleaning is performed with 1 to 5 wt% alkali solution for 5 to 15 minutes, and then ultrasonic cleaning is performed in water for 5 to 10 minutes, and the ultrasonic frequency is 10 to 50 kHz. Specifically, the drying temperature is 115 to 125°C, and the drying time is 10 to 20 minutes. Specifically, the drying temperature may be, but is not limited to, 115°C, 118°C, 120°C, 122°C, 125°C; the drying time may be, but is not limited to, 10 minutes, 12 minutes, 15 minutes, 18 minutes, 20 minutes.

[0019] Furthermore, in step (1) of the present invention, the laser is a femtosecond or picosecond laser.

[0020] Furthermore, the first metal layer and the second metal layer of the present invention are both copper layers.

[0021] Furthermore, the UV irradiation method in step (3) of the present invention includes: irradiating the glass substrate with UV light through a photomask so that only the first metal layer corresponding to the denatured area is irradiated. Correspondingly, the UV irradiation method in step (7) of the present invention includes: irradiating the glass substrate with UV light through a photomask so that only the second metal layer at the bottom of the first blind hole is irradiated.

[0022] Furthermore, both step (4) and step (8) of the present invention include etching with hydrofluoric acid for 4 to 6 minutes. More specifically, the concentration of the hydrofluoric acid is 4 to 6%.

[0023] Furthermore, the cleaning in step (5) and step (9) of the present invention includes: ultrasonic cleaning in a cleaning solution, and the cleaning solution includes but is not limited to water and alkaline solution.

[0024] Furthermore, step (10) of the present invention includes repeating steps (6) to (9) 5 to 7 times.

[0025] Furthermore, the shape of the metallized vertical through-glass via of the present invention is circular or elliptical, which can be selected according to specific application requirements to meet different functional and performance requirements.

[0026] Furthermore, the diameter of the metallized vertical through-glass via of the present invention is 1 to 200 micrometers, and the depth of the metallized vertical through-glass via is 50 to 2000 micrometers.

[0027] Furthermore, the inner wall roughness of the metallized vertical through-glass via of the present invention is less than 20 nanometers. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The process flow chart of the method for preparing the metallized vertical through-glass via of the present invention is shown in FIG. DETAILED DESCRIPTION

[0029] In order to better illustrate the purpose, technical scheme and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of the present invention and should not be used as a limitation of the present invention.

[0030] Please refer to Figure 1 The present invention provides a method for preparing a metallized vertical through-glass via, the steps comprising:

[0031] S1, modifying a target area of ​​a glass substrate 11 by a laser irradiation method to form a modified area 12;

[0032] S2, forming a first metal layer 13 on the glass substrate 11 by sputtering;

[0033] S3, using ultraviolet irradiation to ablate the first metal layer 13 corresponding to the modified area to expose the modified area 12;

[0034] S4, etching the denatured area 12 with a corrosive solution to form a first blind hole 14;

[0035] S5, cleaning and drying the glass substrate 11;

[0036] S6, forming a second metal layer 15 on the glass substrate 11 by sputtering;

[0037] S7, using ultraviolet irradiation to ablate the second metal layer at the bottom of the first blind hole 14 to expose the denatured area 12;

[0038] S8, etching the first blind hole 14 with a corrosive solution to form a second blind hole 17;

[0039] S9, cleaning and drying the glass substrate 11;

[0040] S10 , repeating steps S6 to S9 until all the glass in the modified area 12 is removed, thereby obtaining a metallized vertical glass through hole 18 .

[0041] Among them, S1 also includes first ultrasonically cleaning and drying the glass substrate in a cleaning solution. The cleaning solution includes but is not limited to water and alkali solution. Specifically, use 1-5wt% alkali solution for ultrasonic cleaning for 5-15 minutes, and then ultrasonically clean in water for 5-10 minutes, and the ultrasonic frequency is 10-50kHz. Specifically, the drying temperature is 115-125°C, and the drying time is 10-20 minutes. Specifically, the drying temperature can be but not limited to 115°C, 118°C, 120°C, 122°C, 125°C; the drying time can be but not limited to 10min, 12min, 15min, 18min, 20min.

[0042] The laser in S1 is a femtosecond or picosecond laser. The laser irradiates the target area on the glass substrate, which can cause the glass structure of the area to change (i.e., modify). This modification enhances the interaction between the area and the etching solution, making the modified area easy to be etched in the subsequent etching process.

[0043] Among them, the first metal layer and the second metal layer are both copper layers. Copper material can withstand corrosion from corrosive liquids, and the copper layer on the sidewall of the blind hole is also a seed layer material for the subsequent electroplating process. Specifically, magnetron sputtering or DC sputtering technology can be used in S2 to form a metal copper layer on a glass substrate. More specifically, the thickness and uniformity of the copper layer are ensured by controlling the sputtering time and power.

[0044] The ultraviolet irradiation method in S3 includes: irradiating ultraviolet light onto the glass substrate through a photomask so that only the first metal layer corresponding to the denatured area is irradiated, and the energy of the ultraviolet light is sufficient to ablate the first metal layer to expose the denatured area below.

[0045] Among them, both S4 and S8 include etching with hydrofluoric acid for 4 to 6 minutes. Specifically, the glass in the denatured area is gradually etched away by etching with a corrosive liquid to form a blind hole. The depth and verticality of the blind hole are ensured by controlling the etching conditions to avoid excessive or insufficient etching. More specifically, the concentration of hydrofluoric acid is 4 to 6%.

[0046] Among them, the ultraviolet irradiation method in S7 includes: irradiating ultraviolet light onto the glass substrate through a photomask so that only the second metal layer at the bottom of the first blind hole is irradiated, and the energy of the ultraviolet light is sufficient to ablate the second metal layer at the bottom of the first blind hole to expose the denatured area below.

[0047] Wherein, the cleaning in S5 and S9 includes: ultrasonic cleaning in a cleaning solution, the cleaning solution includes but is not limited to water and alkali solution. Specifically, ultrasonic cleaning is performed with 1-5wt% alkali solution for 5-15 minutes, and then ultrasonic cleaning is performed in water for 5-10 minutes, and the ultrasonic frequency is 10-50kHz. Specifically, the drying temperature in step (5) and step (9) is 115-125°C, and the drying time is 10-20 minutes. Specifically, the drying temperature can be but is not limited to 115°C, 118°C, 120°C, 122°C, 125°C; the drying time can be but is not limited to 10 minutes, 12 minutes, 15 minutes, 18 minutes, 20 minutes.

[0048] Wherein, S10 includes repeating steps (6) to (9) 5 to 7 times. One-time deep etching easily leads to irregular hole shape and poor verticality. Through multiple cycles of metal deposition, ultraviolet ablation and etching with etching liquid, the through hole can be gradually deepened, and the parameters of each cycle (such as sputtering time, ultraviolet irradiation time, etching liquid concentration and etching time) can be precisely controlled to ensure that the depth and uniformity of each etching can be precisely controlled, which can avoid the problem of irregular hole shape caused by one-time deep etching.

[0049] The shape of the metallized vertical glass through hole obtained in S10 is circular or elliptical. It can be selected according to specific application requirements to meet different functional and performance requirements. For example, laser modification can be used to accurately control the shape of the modified area to be circular, so that the through hole is suitable for standard applications that require high symmetry and uniformity.

[0050] The diameter of the metallized vertical through-glass hole obtained in S10 is 1 to 200 microns, and the depth of the metallized vertical through-glass hole is 50 to 2000 microns.

[0051] The inner wall roughness of the metallized vertical glass through hole obtained in S10 is less than 20 nanometers. The low-roughness surface can reduce the loss during the current transmission process, improve the efficiency and stability of the current transmission, and facilitate the subsequent electroplating process.

[0052] The technical solution of the present application is described in detail below in conjunction with specific embodiments.

[0053] Example 1

[0054] This embodiment provides a method for preparing a metallized vertical through-glass via, the steps comprising:

[0055] (1) The glass substrate was sequentially cleaned by ultrasonic cleaning (frequency of 50 kHz) in 5 wt % sodium hydroxide solution for 8 min, ultrasonic cleaning (frequency of 20 kHz) in water for 10 min, and dried at 120° C. for 12 min, and then the target area of ​​the glass substrate was irradiated and modified by femtosecond laser to form a circular denatured area, wherein the parameters of the laser irradiation were: energy of 120 μJ, pulse width of 200 fs, frequency of 350 kHz, and single pulse;

[0056] (2) depositing metallic copper on the surface of the glass substrate to form a first metal layer by magnetron sputtering, wherein the parameters of the magnetron sputtering are: power of 3 kW, bias voltage of 300 W, and working gas pressure of 0.5 Pa;

[0057] (3) irradiating ultraviolet light only onto the first metal layer corresponding to the denatured area through a photomask to ablate and expose the denatured area, wherein the parameters of the ultraviolet irradiation are: energy of 300 μJ, pulse width of 1800 ps, ​​frequency of 2000 kHz, and two pulses;

[0058] (4) etching the denatured area with 5% hydrofluoric acid for 5 minutes to form a first blind hole;

[0059] (5) The glass substrate was cleaned in 5 wt % sodium hydroxide solution by ultrasonic cleaning (frequency: 50 kHz) for 8 min, cleaned in water by ultrasonic cleaning (frequency: 20 kHz) for 10 min, and dried at 120° C. for 12 min.

[0060] (6) depositing metallic copper on the glass substrate to form a second metal layer by magnetron sputtering, wherein the parameters of the magnetron sputtering are: power of 3 kW, bias voltage of 300 W, and working gas pressure of 0.5 Pa;

[0061] (7) irradiating ultraviolet light only onto the second metal layer at the bottom of the first blind hole through a photomask for ablation, wherein the parameters of the ultraviolet irradiation are: energy of 300 μJ, pulse width of 1800 ps, ​​frequency of 2000 kHz, and two pulses;

[0062] (8) etching the denatured area with 5% hydrofluoric acid for 5 minutes to form a first blind hole;

[0063] (9) The glass substrate was cleaned in 5 wt % sodium hydroxide solution by ultrasonic cleaning (frequency: 50 kHz) for 8 min, cleaned in water by ultrasonic cleaning (frequency: 20 kHz) for 10 min, and dried at 120° C. for 12 min.

[0064] (10) Repeat steps (6) to (9) six times until all the glass in the modified area is removed to obtain a metallized vertical glass through hole.

[0065] The glass substrate with the metallized vertical glass through hole obtained in Example 1 was observed under a Keyence VK-3000 microscope. The focal length and viewing angle of the microscope were adjusted to make the outline of the through hole clearly visible. The coordinate reading system of the microscope was used to directly read the diameter of the metallized vertical glass through hole as 50 microns and the depth as 1500 microns. The coordinate reading system of the microscope was used to directly read the diameters at different depths to calculate the taper, which was 0.012 degrees. The inner wall roughness of the through hole was measured to be 2.56 nanometers using the built-in measuring tool.

[0066] The glass substrate with the metallized vertical through-glass hole obtained in Example 1 was baked in an oven at 110° C. for 4 hours, and the bonding strength of the metal copper layer on the glass after baking was tested by the cross-grid method. The test results showed that there was no peeled copper on the 3M tape.

[0067] In summary, the present invention uses laser modification to accurately control the shape and depth of the modified area, so that the subsequent etching solution can evenly etch the glass in the modified area, ensuring the verticality of the through hole; at the same time, a metal layer is formed by sputtering, and the side wall metal layer is retained by ablating the bottom metal layer, so that the side wall of the blind hole is effectively protected during the etching of the bottom glass and will not be affected by the etching solution, which ensures the integrity of the side wall of the through hole and further ensures the verticality of the through hole; at the same time, by repeating steps (6) to (9), that is, by multiple cycles of metal deposition, ultraviolet ablation, and etching with etching solution, the through hole can be gradually deepened, and the side wall of the blind hole is effectively protected in each cycle, ensuring the uniformity and verticality of each etching, and finally forming a vertical through hole with a high aspect ratio and consistent diameters of the upper and lower parts. In addition, laser irradiation of the target area causes tiny unevenness on the glass surface, which increases the contact area between the first metal layer and the glass surface and improves the adhesion of the metal. At the same time, the corrosive liquid not only physically changes the roughness of the glass surface during the etching of the denatured area, but also chemically activates the surface. The rough surface provides more physical adsorption sites, making it easier for the metal to stably adhere to the hole wall, and the enhanced chemical activity of the rough surface can further improve the adhesion between the metal layer and the hole wall. At the same time, the present application adopts sputtering to form a metal layer, which can achieve uniform coverage and ensure the uniformity and density of the metal layer on the side wall of the blind hole. Therefore, the preparation method of the present invention can produce a glass through hole with a high aspect ratio and good verticality, which can greatly improve the current loss problem; at the same time, it ensures that the metal layer can stably and evenly adhere to the inner wall of the glass through hole, which provides a good seed layer for subsequent electroplating.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a metallized vertical through-glass via, characterized in that the steps include: (1) modifying a target area of ​​a glass substrate by laser irradiation to form a denatured area; (2) forming a first metal layer on the glass substrate by sputtering; (3) ablating the first metal layer corresponding to the modified area by ultraviolet irradiation to expose the modified area; (4) etching the denatured area with a corrosive solution to form a first blind hole; (5) cleaning and drying the glass substrate; (6) forming a second metal layer on the glass substrate by sputtering; (7) ablating the second metal layer at the bottom of the first blind hole by ultraviolet irradiation; (8) etching the first blind hole using a corrosive solution to form a second blind hole; (9) cleaning and drying the glass substrate; (10) Repeat steps (6) to (9) until all the glass in the modified area is removed to obtain a metallized vertical glass through hole.

2. The method for preparing a metallized vertical through glass via according to claim 1, characterized in that: Step (1) also includes firstly ultrasonically cleaning and drying the glass substrate in a cleaning solution.

3. The method for preparing a metallized vertical through glass via according to claim 1, characterized in that: The laser in step (1) is a femtosecond or picosecond laser.

4. The method for preparing a metallized vertical through glass via according to claim 1, characterized in that: The first metal layer and the second metal layer are both copper layers.

5. The method for preparing a metallized vertical through glass via according to claim 1, characterized in that: Both step (4) and step (8) include etching with hydrofluoric acid for 4 to 6 minutes.

6. The method for preparing a metallized vertical through glass via according to claim 1, characterized in that: Step (10) includes repeating steps (6) to (9) 5 to 7 times.

7. The method for preparing a metallized vertical through glass via according to claim 1, characterized in that: The shape of the metallized vertical through-glass via is circular or elliptical.

8. The method for preparing a metallized vertical through glass via according to claim 1, characterized in that: The diameter of the metallized vertical through-glass hole is 1 to 200 microns, and the depth of the metallized vertical through-glass hole is 50 to 2000 microns.

9. The method for preparing a metallized vertical through glass via according to claim 1, characterized in that: The inner wall roughness of the metallized vertical through-glass hole is less than 20 nanometers.

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