Etching liquid composition for glass etching, method for etching glass, and method for producing glass

Abstract

Provided is an etching liquid composition that makes it possible to etch glass having good hole shape at a high etching rate. The etching liquid composition for glass etching comprises 2-8 mol / L of a metal hydroxide and 0.5-1.5 mol / L of a hydroxycarboxylic acid or salt thereof.

Description

Etching solution composition for glass etching, glass etching method, and glass manufacturing method

[0001] The present disclosure relates to an etching solution composition for etching glass, a method for etching glass, and a method for manufacturing glass.

[0002] In recent years, in the semiconductor field, performance improvements through silicon microfabrication are approaching their physical and cost limits. For this reason, there has been active research into improving performance through advanced semiconductor post-processing and the materials used therein. Glass plates with micro-through holes (Through Glass Via, TGV) are in demand for many applications, such as glass interposers and glass core substrates, and manufacturing methods for these are being researched. For example, there is a method in which a glass substrate is modified by irradiating it with a laser, and then the modified area is anisotropically processed in a location-selective manner by etching with a chemical solution.

[0003] A common method for etching glass is to use a chemical solution containing hydrofluoric acid. However, the compounds produced by the reaction, such as hexafluorosilicic acid and hexafluoroaluminic acid, can form salts with alkaline earth metals, which are network modifiers in the glass, resulting in the formation of precipitates. In microhole processing, these precipitates can hinder smooth etching, making it extremely difficult to form holes of the desired shape. For this reason, an etching method using a strongly alkaline aqueous solution has been proposed.

[0004] As a method for processing micropores using a strongly alkaline chemical solution, for example, an etching process using a basic aqueous etching solution having a pH of more than 12, which contains at least one complexing agent, and in which at least one eluted component forms a complex with the complexing agent, has been reported (see, for example, Patent Document 1).

[0005] Special Publication No. 2023-552866

[0006] An object of one embodiment of the present disclosure is to provide an etching solution composition that can achieve glass etching with a high etching rate and good hole shapes.

[0007] An etching solution composition according to an embodiment of the present disclosure is an etching solution composition for glass etching, comprising a metal hydroxide at a concentration of 2 mol / L or more and 8 mol / L or less, and a hydroxycarboxylic acid or a salt thereof at a concentration of 0.5 mol / L or more and 1.5 mol / L or less.

[0008] According to one embodiment of the present disclosure, it is possible to provide an etching solution composition that can achieve etching of glass with a high etching rate and good hole shapes.

[0009] Fig. 1 is a schematic diagram showing the flow of a method for manufacturing glass according to a first embodiment. Fig. 2 is a schematic diagram showing the flow of a method for manufacturing glass according to the first embodiment. Fig. 3 is a schematic diagram showing the flow of a method for manufacturing glass according to the first embodiment. Fig. 4 is a schematic diagram showing the flow of a method for manufacturing glass according to a second embodiment. Fig. 5 is a schematic diagram showing the flow of a method for manufacturing glass according to the second embodiment.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or similar components are denoted by the same reference numerals, and their description may be omitted. In the specification, the symbol "to" indicating a numerical range means that the numerical values ​​before and after it are included as the lower and upper limits. The numerical range includes the range rounded up or down. Hereinafter, the composition range of each component of the glass is expressed in mol% based on the oxide.

[0011] (Etching Solution Composition) The etching solution composition of the present embodiment is an etching solution composition for glass etching, and contains a metal hydroxide at 2 mol / L or more and 8 mol / L or less, and a hydroxycarboxylic acid or a salt thereof at 0.5 mol / L or more and 1.5 mol / L or less, and further contains other components as necessary.

[0012] In conventional etching processes using strongly alkaline chemicals, calcium ions, magnesium ions, and the like eluted from glass, such as aluminosilicate glass, form precipitates such as aluminates, silicates, and hydroxides, inhibiting etching inside the pores. Furthermore, the flow inside the pores forms a closed vortex, and as etching progresses, precipitates accumulate, and the base component and complexing agent decrease, resulting in a decrease in the etching rate (see, for example, Journal of the Electrochemical Society, 1983, 130.8: 1722). On the other hand, refreshing the pore interior by applying centrifugal force can increase the etching rate. However, there remains a trade-off between etching rate and processability, and there is still a need for glass etching that achieves both a high etching rate and a good pore shape.

[0013] The prior art described in Patent Document 1 specifically discloses an etching method using a chemical solution containing 0.3 mol / L sodium gluconate and having a pH greater than 12, demonstrating that the addition of sodium gluconate improves the removability of glass material and slightly increases the etching rate. However, the etching method using the chemical solution disclosed in Patent Document 1 did not achieve an etching rate that was practically sufficient. Furthermore, there was no mention of the effect of adding sodium gluconate on improving hole shape. Therefore, there is a need for an etching solution composition that can achieve glass etching with a high etching rate and good hole shape.

[0014] The present inventors have conducted extensive research to solve the problems of the conventional art and the above-mentioned problems, and as a result have found that an etching solution composition containing 2 mol / L or more and 8 mol / L or less of a metal hydroxide and 0.5 mol / L or more and 1.5 mol / L or less of a hydroxycarboxylic acid or a salt thereof can be used to etch glass at a high etching rate and with good hole shapes, leading to the completion of the present invention.

[0015] <Metal Hydroxide> The metal hydroxide is a hydroxide of a metal element and can be appropriately selected depending on the purpose without any particular limitation as long as it is basic, and suitable examples thereof include sodium hydroxide (NaOH), potassium hydroxide (KOH), etc. These may be used alone or in combination of two or more.

[0016] The content of the metal hydroxide in the etching solution composition is from 2 mol / L to 8 mol / L, preferably from 2 mol / L to 7 mol / L, more preferably from 3 mol / L to 7 mol / L, and particularly preferably from 3 mol / L to 6 mol / L, from the viewpoint of improving the planarity rate and straightness.

[0017] <Hydroxycarboxylic Acid and / or Salt Thereof> The hydroxycarboxylic acid and / or salt thereof is not particularly limited and can be appropriately selected depending on the purpose, so long as it is a compound having a hydroxyl group and a carboxyl group and / or a salt thereof. Examples include sugar acids such as aldonic acid, uronic acid, and aldaric acid; hydroxyethylethylenediaminetriacetic acid (HEDTA), hydroxyethyliminodiacetic acid (HIDA), dihydroxyethylglycine (DHEG), 3-hydroxy-2,2'-iminodisuccinic acid, citric acid, lactic acid, glycolic acid, hydroxybutyric acid, malic acid, tartaric acid, salicylic acid, vanillic acid, protocatechuic acid, gallic acid, mandelic acid, benzilic acid, ferulic acid, sinapic acid, serine, threonine, and tyrosine; and salts thereof. These may be used alone or in combination of two or more.

[0018] Examples of the aldonic acid include glyceric acid, xylonic acid, gluconic acid, heptogluconic acid, lactobionic acid, and ascorbic acid. Examples of the salt include sodium salts and potassium salts. Among these, gluconic acid and sodium gluconate are preferred.

[0019] The content of the hydroxycarboxylic acid and / or salt thereof is from 0.5 mol / L to 1.5 mol / L, preferably from 0.6 mol / L to 1.5 mol / L, in terms of improving the planarity rate and straightness of the etching solution composition.

[0020] <Other Components> The other components can be appropriately selected depending on the purpose as long as the effects of the present embodiment are not impaired. Examples of the other components include complexing agents other than hydroxycarboxylic acids and / or salts thereof, such as phosphorus ligands, Lewis bases, oxidizing agents, reducing agents, inorganic salts, sugars, amine compounds, carboxylic acid compounds, aminocarboxylic acid compounds, polymeric dispersants, surfactants, organic solvents, rheology control agents, and thickeners.

[0021] (Glass Etching Method) The glass etching method of the present embodiment includes a step (step S001) of etching glass using the etching liquid composition of the present embodiment described above, and further includes other steps as necessary.

[0022] <Step S001> Step S001 is a step of etching glass using the etching solution composition. The etching solution composition can be appropriately selected from the items described in the etching solution composition of this embodiment.

[0023] The method for etching glass is not particularly limited as long as the etching solution composition is used, and any known method can be appropriately selected depending on the purpose, but immersing the glass in the etching solution composition is preferred. From the viewpoint of easy control of the etching rate, the etching temperature is preferably 20°C to 150°C, more preferably 50°C to 120°C, and particularly preferably 80°C to 110°C. From the viewpoint of stabilizing quality, the etching time is preferably 1 hour to 300 hours, more preferably 1 hour to 275 hours, even more preferably 1 hour to 244 hours, even more preferably 1 hour to 100 hours, particularly preferably 2 hours to 50 hours, particularly preferably 2 hours to 30 hours, and most preferably 2 hours to 20 hours.

[0024] From the viewpoint of refreshing the etching solution composition inside the holes in the glass during etching, it is preferable to flow the etching solution composition. Suitable examples include a method of filling a closed space with the etching solution composition and etching while applying liquid pressure, as described in JP 2020-001959 A; a method of etching by applying ultrasonic waves (for example, 40 kHz to 192 kHz) to a glass substrate, as described in JP 2016-534017 A; a method of etching while stirring the etching solution composition with a vibrator immersed in the etching solution composition, as described in JP 2020-066551 A; and a method of etching under conditions in which the average relative speed of the etching solution composition to the glass is faster in the second etching step than in the first etching step, as described in JP 2023-082984 A.

[0025] -Glass- The glass is not particularly limited and can be appropriately selected depending on the purpose. ２ O, Na ２ O.K. ２ Aluminosilicate glass containing at least one selected from the group consisting of O, MgO, CaO, SrO, and BaO is preferred. ２ O, Na ２ O and K ２ It is more preferable that the total content of O is 0 mol% to 10 mol%, and the total content of MgO, CaO, SrO, and BaO is 0 mol% to 30 mol%. The elements contained in the glass are not particularly limited, and any element may be contained depending on the desired physical properties. In this specification, glass also includes crystallized glass.

[0026] SiO in the glass ２ The content of Al in the glass is preferably 40 mol % to 99 mol %, more preferably 55 mol % to 90 mol %, and particularly preferably 60 mol % to 85 mol %, from the viewpoint of improving the flatness rate and straightness.２ O ３ The content of B in the glass is preferably 1 mol % to 40 mol %, more preferably 1 mol % to 30 mol %, and even more preferably 3 mol % to 20 mol %, from the viewpoint of improving the flatness rate and straightness. ２ O ３ From the viewpoint of enhancing the planar rate and straightness, the content is preferably 0 mol % to 30 mol %, more preferably 1 mol % to 25 mol %, even more preferably 3 mol % to 20 mol %, and particularly preferably 5 mol % to 15 mol %.

[0027] SiO ２ , Al ２ O ３ , and / or B ２ O ３ has the effect of forming a glass network, and Li ２ O, Na ２ O.K. ２ O, MgO, CaO, SrO, and / or BaO have the effect of modifying the glass network and are generally referred to as network modifier oxides. The glass may be appropriately selected depending on the intended use, taking into consideration the CTE, refractive index, density, Young's modulus, relative dielectric constant, dielectric loss tangent, etc.

[0028] (Method for Producing Glass) The method for producing glass of this embodiment is a method for producing glass having a via, and includes a step of etching glass having a modified portion using the etching solution composition of this embodiment described above to form a via, and further includes other steps, as necessary, such as a step of forming a modified portion. The via may be a through via that penetrates one surface of the glass and the other surface, or a non-through via that has an opening on one surface of the glass and no opening on the other surface, either of which can be appropriately selected depending on the purpose.

[0029] First Embodiment A method for manufacturing glass according to a first embodiment will be described below with reference to Figures 1 to 3. Figures 1 to 3 are schematic diagrams showing the flow of the method for manufacturing glass according to the first embodiment, illustrating aspects of the method for manufacturing glass having through vias. The method for manufacturing glass according to the first embodiment includes, for example, steps S101 to S102. In step S101, a laser is irradiated onto a glass substrate at a position where a via is to be formed, thereby forming a modified portion. In step S102, the glass having the modified portion is etched to form the plurality of vias.

[0030] <S101> In step S101, a laser is irradiated onto a glass substrate at a position where a via is to be formed to form a modified portion. This forms a modified portion by modifying the position where the via is to be formed, and glass having the modified portion is formed. The position where the via is to be formed is modified by receiving energy from the laser irradiation, and becomes a modified portion that has a property of being easily etched.

[0031] First, a glass substrate 110 is prepared. As shown in Fig. 1, the glass substrate 110 has a first surface 112 and a second surface 114 opposite to the first surface.

[0032] The glass substrate 110 can be appropriately selected from the glasses described in the etching method of this embodiment, and may be a laminate having additional layers such as inorganic or organic films. When the glass is used for packaging semiconductor devices, alkali-free glass is preferred. This is because alkali-containing glass may precipitate alkali components in the glass and adversely affect the semiconductor devices.

[0033] The average thickness of the glass substrate is not particularly limited and can be appropriately selected depending on the purpose, and may be, for example, 0.05 mm to 3.0 mm.

[0034] Next, a laser is irradiated from the first surface 112 of the glass substrate 110 to a position where a via is to be formed, thereby forming a modified portion 120. Figure 2 shows a schematic cross-sectional view of the glass substrate 110 having the modified portion 120 after laser irradiation. When manufacturing glass having through vias, a plurality of modified portions 120 are formed that communicate from the first surface 112 to the second surface 114. In the modified portion 120, the opening in the first surface 112 is referred to as a first initial opening 122, and the opening in the second surface 114 is referred to as a second initial opening 124.

[0035] The via formation position and modified portion may be a through via formation position and modified portion (e.g., 120 in FIG. 2) that communicates throughout the thickness direction of the glass substrate, or a non-through via formation position and modified portion (e.g., 230 in FIG. 4) that communicates from one surface of the glass substrate to a predetermined depth, either of which can be appropriately selected depending on the purpose. Through vias may be connected to each other to form a through via with an irregular shape, or non-through vias may be connected to each other to form a cavity-shaped, pocket-shaped, or groove-shaped via.

[0036] The laser is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a green laser and a UV laser. Furthermore, as a laser irradiation method, it is preferable to use a short-pulse laser (e.g., a picosecond laser, a nanosecond laser, or a femtosecond laser). Specifically, a modified portion can be formed by irradiating aluminosilicate glass having an average thickness of 1.1 mm with a green picosecond laser (e.g., a wavelength of 532 nm, a pulse width of 10 ps) with pulse energy of 40 μJ to 300 μJ, with one to several shots per planned formation position (e.g., 100 μJ, one shot).

[0037] <S102> In step S102, the glass having the modified portion is etched using the etching solution composition to form a via. This produces glass having a via. The method for etching glass is not particularly limited as long as the etching solution composition and the glass having the modified portion are used, and any method described in connection with the etching method of this embodiment can be appropriately selected.

[0038] Next, in step S102, the glass substrate 110 having the modified portion 120 is etched using an etching solution composition to form a plurality of through vias 140. At this time, the first initial opening 122 is expanded to form a first opening 142, and the second initial opening 124 is expanded to form a second opening 144. Note that during the etching process, the surface of the glass substrate 110 is also etched, and the thickness of the glass substrate 110 is reduced to t ０ From t １ Figure 3 shows a schematic cross-sectional view of the glass with through via 140 after etching.

[0039] Therefore, the first surface 112 and the second surface 114 of the glass substrate 110 are each transformed into a new surface after the etching process. However, in order to avoid complication of explanation in this application, the mutually opposing surfaces of the glass substrate 110 after the etching process will be referred to as the "first surface 112" and the "second surface 114."

[0040] In this manner, glass having through vias 140 can be manufactured as shown in FIG.

[0041] The diameter of the vias is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 μm to 500 μm, and more preferably 10 μm to 300 μm. When the via diameter is 1 μm to 500 μm, glass can be produced that has a high etching rate and a good hole shape.

[0042] Here, the via diameter is the top hole diameter φ on the first surface 112, which is the laser irradiation side in step S101. １ , the bottom hole diameter φ in the second surface 114 ２ , and / or top hole diameter φ １ and bottom hole diameter φ ２ The average pore size is the average value of the above.

[0043] The etching rate, which is an index of etching, can be evaluated by the "flattening rate," which is the rate at which the glass thickness is reduced per etching time [μm / hour]. If the flattening rate is too fast, it becomes difficult to control the quality, and if it is too slow, productivity decreases. The flattening rate can be appropriately selected depending on the initial thickness [μm] of the glass substrate to be processed, and is preferably initial thickness / 300 [μm / hour] or more, more preferably initial thickness / 275 [μm / hour] or more, even more preferably initial thickness / 244 [μm / hour] or more, even more preferably initial thickness / 220 [μm / hour] or more, particularly preferably initial thickness / 212 [μm / hour] or more, and most preferably initial thickness / 200 [μm / hour] or more. Specific numerical values, for example, when the initial plate thickness is 1,100 μm, are preferably 3.6 μm / hour or more, more preferably 4.0 μm / hour or more, even more preferably 4.5 μm / hour or more, even more preferably 5.0 μm / hour or more, particularly preferably 5.2 μm / hour or more, and most preferably 5.5 μm / hour or more.

[0044] Specifically, the average thickness t of the glass before etching ０ [μm], and the average thickness t of the glass after etching １ The thickness [μm] is measured and calculated using a plate thickness measuring device (for example, a multicolor laser coaxial displacement meter with a CL-L015 (manufactured by Keyence Corporation) as the sensor head), and the "flat rate" can be calculated by dividing the thickness reduction by the etching time T [hours] using the following formula. (Formula) Flat rate [μm / hour] = (t ０ -t １ ) / T

[0045] Furthermore, when the via is a through via, the goodness of the hole shape can be evaluated by "straightness," which is the ratio of the "neck diameter" to the "average hole diameter," which is the average value of the top hole diameter and the bottom hole diameter. From the viewpoint of enabling finer wiring in a subsequent process, the straightness is preferably 0.3 or more, more preferably 0.33 or more, and particularly preferably 0.35 or more.

[0046] Specifically, the top hole diameter φ of the opening of the through via is measured using a digital microscope (for example, VHX-8000, manufactured by Keyence Corporation) for the glass after etching. １ , and bottom hole diameter φ ２ The measurement is performed using a particle analysis function, and the circle equivalent diameter is taken as the hole diameter. Next, the glass is cut, and the cross section including the plurality of through vias is observed, and the constriction diameter φ at the constriction portion 190 is measured. ｗ The distance between the two narrowest points of each through via is measured. The "straightness" can be calculated using the following formula: (Formula) Straightness = Neck diameter / Average hole diameter

[0047] Second Embodiment A method for manufacturing glass according to a second embodiment will be described below with reference to FIGS. 4 and 5. FIGS. 4 and 5 are schematic diagrams showing the flow of the method for manufacturing glass according to the second embodiment, illustrating aspects of the method for manufacturing glass having non-through vias. With the exception of forming non-through vias, the items described in the first embodiment can be selected as appropriate. The method for manufacturing glass according to the second embodiment includes, for example, steps S201 and S202. In step S201, a laser is irradiated onto a position on the glass substrate where a via is to be formed, to form a modified portion. In step S202, the glass having the modified portion is etched to form the plurality of vias.

[0048] In step S201, a laser is irradiated onto a position where a via is to be formed from the first surface 212 of the glass substrate 210 to form a modified portion 230. The glass substrate 210 has a first surface 212 and a second surface 214 opposite to the first surface 212. The glass substrate 210 can be appropriately selected from the glass substrate 110 and the glass described in the etching method of this embodiment.

[0049] 4 is a schematic cross-sectional view of the glass substrate 210 having the modified portion 230 after laser irradiation. When manufacturing glass having a non-penetrating via, a predetermined depth d １ A modified portion 230 of a non-penetrating via that communicates with the first surface 212 is formed. In the modified portion 230, an opening in the first surface 212 is referred to as a first initial opening 232.

[0050] Next, in step S202, the glass substrate 210 having the modified portion 230 is etched using the etching solution composition to a depth d ２ At this time, the first initial opening 232 is expanded to form the first opening 252. Note that during the etching process, the surface of the glass substrate 210 is also etched, and the thickness of the glass substrate 210 is reduced to t ０ From t １ 5 shows a schematic cross-sectional view of glass with blind vias 250 after etching.

[0051] In this way, glass having non-penetrating vias 250 can be manufactured as shown in FIG.

[0052] Top diameter of via φ １ The via diameter is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 μm to 500 μm, and more preferably 10 μm to 300 μm. When the via hole diameter is 1 μm to 500 μm, glass can be produced that has a high etching rate and a good hole shape.

[0053] The depth of the non-penetrating via 250 is d ２ [μm], the aspect ratio d ２ / φ １ For example, it may be 1 or more.

[0054] The etching rate, which is an index of etching, can be evaluated by the planarization rate when the via is a non-through via, as in the case of a through via. If the planarization rate is too fast, it is difficult to control the quality, and if it is too slow, productivity will be poor. The planarization rate can be appropriately selected according to the initial thickness [μm] of the glass substrate to be processed, and is preferably initial thickness / 300 [μm / hour] or more, more preferably initial thickness / 275 [μm / hour] or more, even more preferably initial thickness / 244 [μm / hour] or more, even more preferably initial thickness / 220 [μm / hour] or more, particularly preferably initial thickness / 212 [μm / hour] or more, and most preferably initial thickness / 200 [μm / hour] or more. Specific numerical values, for example, when the initial plate thickness is 1,100 μm, are preferably 3.6 μm / hour or more, more preferably 4.0 μm / hour or more, even more preferably 4.5 μm / hour or more, even more preferably 5.0 μm / hour or more, particularly preferably 5.2 μm / hour or more, and most preferably 5.5 μm / hour or more.

[0055] When the via is a non-through via, the aspect ratio d ２ / φ １ The ratio is preferably 1 or more, more preferably 5 or more, and even more preferably 10 or more.

[0056] The experimental data will be explained below. Examples 2 to 5, 8 to 11, and 14 to 17 are working examples, and Examples 1, 6 to 7, 12 to 13, and 18 to 25 are comparative examples.

[0057] (Example 1) <Formation of modified portions> An aluminosilicate-based alkali-free glass (EN-A1; manufactured by AGC Inc., size: 12 mm x 25 mm) with an average thickness of 1.1 mm was used as the glass substrate. A laser was irradiated at the planned via formation positions for forming through vias penetrating from one surface of the glass substrate to the other surface, to form modified portions. A green picosecond laser (wavelength 532 nm, pulse width 10 ps, ​​pulse energy 100 μJ) was used as the laser, and one shot was irradiated per planned formation position. The pitch between adjacent modified portions was 300 μm, and 3,200 modified portions were arranged in a 40 x 80 grid.

[0058] <Etching> 3.00 mol / L NaOH and 0.15 mol / L sodium gluconate were added to water and mixed to prepare the etching solution composition of Example 1 (see Table 1). 14 mL of the etching solution composition was placed in a 15 mL centrifuge tube made of polymethylpentene, the tube was capped, and the tube was placed in a shaker and heated to 90°C with rotary shaking at a shaking speed of 120 rpm. A glass substrate having a modified portion was immersed in the heated etching solution composition, the lid was placed, and the substrate was shaken for 15 hours to perform etching, thereby producing the glass of Example 1 having a through via.

[0059] <Evaluation> The flatness rate and straightness were evaluated and an overall evaluation was carried out according to the following procedures. The results are shown in Table 1.

[0060] <<Plane Rate>> Average thickness of glass before etching t ０ [μm], and the average thickness t of the glass after １The glass thickness reduction rate [μm] was measured and calculated using a multicolor laser coaxial displacement meter with a plate thickness measuring device (CL-L015, manufactured by Keyence Corporation) as the sensor head. Next, the reduced thickness was divided by the etching time T [hours] to calculate the "flattening rate" as the rate at which the glass thickness was reduced per etching time [μm / hour] using the following formula, and evaluation was performed based on the following evaluation criteria. A grade of B or higher is a practical standard. The evaluation criteria differ depending on the metal hydroxide concentration in the chemical solution. This is because as the chemical solution concentration increases, the cost of the chemical solution increases, and therefore faster processing is required, changing the standard for cost-effectiveness. (Formula) Flattening rate [μm / hour] = (t ０ -t １ ) / T -Evaluation Criteria- When the metal hydroxide concentration in the chemical solution was 3.00 mol / L or less, the evaluation was based on the following criteria. A: Planarization rate was 4.5 [μm / hour] or more B: Planarization rate was 4.0 [μm / hour] or more and less than 4.5 [μm / hour] C: Planarization rate was less than 4.0 [μm / hour] When the metal hydroxide concentration in the chemical solution exceeded 3.00 mol / L, the evaluation was based on the following criteria. A: Planarization rate was 5.45 [μm / hour] or more B: Planarization rate was 4.0 [μm / hour] or more and less than 5.45 [μm / hour] C: Planarization rate was less than 4.0 [μm / hour]

[0061] <<Straightness>> After etching, the glass was measured using a digital microscope (VHX-8000, manufactured by Keyence Corporation) to determine the top hole diameter φ of the opening of the through-via. １ , and bottom hole diameter φ ２ The particle analysis function was used for the measurement, and the circle equivalent diameter was taken as the pore diameter. Top pore diameter φ １ and bottom hole diameter φ ２ The average value was calculated as the "average pore size."

[0062] Next, the glass is cut, and a cross section including a plurality of through vias is observed. The diameter φ of the constriction at the constriction 190 is measured. ｗThe distance between the two points at the narrowest part of each through via was measured as 0. If the via was not penetrated, it was taken as 0. The "straightness" was calculated using the following formula and evaluated based on the following evaluation criteria. B or higher is a practical level. (Formula) Straightness = neck diameter / average hole diameter - Evaluation criteria - A: Straightness is 0.33 or more B: Straightness is 0.3 or more and less than 0.33 C: Straightness is 0.1 or more and less than 0.3 D: Straightness is less than 0.1

[0063] <<Overall Evaluation>> An overall evaluation was performed based on the following evaluation criteria. B or higher is a practical level, but A is preferable. -Evaluation criteria- A: The evaluation criteria for flat rate and straightness are both A. B: The evaluation criteria for flat rate and straightness include B, but do not include C or D. C: The evaluation criteria for flat rate and straightness include C or D.

[0064] (Examples 2 to 25) Etching solution compositions of Examples 2 to 21 were prepared, and glasses of Examples 2 to 25 were produced, respectively, in the same manner as in Example 1, except that the compositions of the etching solution compositions in Example 1 were changed as shown in Tables 1 and 2. Then, in the same manner as in Example 1, the flatness rate and straightness were evaluated, and an overall evaluation was performed. The results are shown in Tables 1 and 2.

[0065]

[0066]

[0067]

[0068]

[0069] The results in Tables 1 to 4 indicate that a metal hydroxide (NaOH) of 2 mol / L or more and 8 mol / L or less is suitable for etching. Furthermore, it was found that etching properties are significantly improved when a high concentration (0.5 mol / L or more) of hydroxycarboxylic acid and / or its salt is used, which is unimaginable in the prior art. The upper limit was 1.5 mol / L.

[0070] From the above, it was found that an etching solution composition, an etching method, and a method for manufacturing glass having a via can be provided that can achieve glass etching in which the etching rate is high due to an excellent flatness rate and the hole shape is good due to an excellent straightness rate in the examples with an overall rating of A or B.

[0071] The etching solution composition, etching method, and method for manufacturing glass having vias according to the present disclosure have been described above, but the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0072] The following supplementary notes are disclosed regarding the above embodiments, etc. [Supplementary Note 1] An etching solution composition for glass etching, comprising a metal hydroxide of 2 mol / L or more and 8 mol / L or less, and a hydroxycarboxylic acid and / or a salt thereof of 0.5 mol / L or more and 1.5 mol / L or less. [Supplementary Note 2] The etching solution composition according to Supplementary Note 1, wherein the metal hydroxide is sodium hydroxide and / or potassium hydroxide. [Supplementary Note 3] The etching solution composition according to Supplementary Note 1 or 2, wherein the hydroxycarboxylic acid and / or a salt thereof is gluconic acid and / or a salt thereof. [Supplementary Note 4] A glass etching method, comprising a step of etching glass with the etching solution composition according to any one of Supplementary Notes 1 to 3. [Supplementary Note 5] In the glass, Li ２ O, Na ２ O and K ２ The method for etching glass according to Appendix 4, wherein the total content of O is 0 mol % to 10 mol %, and the total content of MgO, CaO, SrO, and BaO is 0 mol % to 30 mol %. [Appendix 6] A method for producing glass having a via, comprising the step of etching glass having a modified portion using the etching solution composition according to any one of Appendixes 1 to 3 to form a via.

[0073] This application claims priority based on Japanese Patent Application No. 2024-110503, filed on July 9, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0074] 110 Glass substrate 112 First surface 114 Second surface 120 Modified portion 122 First initial opening 124 Second initial opening 140 Through via 142 First opening 144 Second opening 190 Narrowed portion 210 Glass substrate 212 First surface 214 Second surface 230 Modified portion 232 First initial opening 250 Non-through via 252 First opening

Claims

1. An etching solution composition for glass etching, comprising: a metal hydroxide of 2 mol / L or more and 8 mol / L or less; and a hydroxycarboxylic acid and / or a salt thereof of 0.5 mol / L or more and 1.5 mol / L or less.

2. The etching solution composition according to claim 1, wherein the metal hydroxide is sodium hydroxide and / or potassium hydroxide.

3. The etching solution composition according to claim 1, wherein the hydroxycarboxylic acid and / or its salt is gluconic acid and / or its salt.

4. A method for etching glass, comprising the step of etching glass using the etching solution composition according to any one of claims 1 to 3.

5. In the glass, Li ２ O, Na ２ O and K ２ 5. The method for etching glass according to claim 4, wherein the total content of O is 0 mol % to 10 mol %, and the total content of MgO, CaO, SrO, and BaO is 0 mol % to 30 mol %.

6. A method for manufacturing glass having a via, comprising the step of etching glass having a modified portion using the etching solution composition according to any one of claims 1 to 3 to form a via.

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