CN113767075A

CN113767075A - Etching solution for glass and method for producing glass substrate

Info

Publication number: CN113767075A
Application number: CN202080032093.XA
Authority: CN
Inventors: 西川晴香; 岛田和哉; 永井忠; 三好雄三; 富家夏树; 大小田健太; 柏原康宏; 齐藤俊介; 大山阳照; 林笃嗣; 福成良介; 石垣畅规; 元持健; 久米贵大
Original assignee: NSC Co Ltd; Matsushita Electric Industrial Co Ltd
Current assignee: NSC Co Ltd; Panasonic Holdings Corp
Priority date: 2019-03-05
Filing date: 2020-02-03
Publication date: 2021-12-07
Anticipated expiration: 2040-02-03
Also published as: JP2020142941A; TW202043441A; JP6803018B2; WO2020179312A1; CN113767075B

Abstract

The invention provides a method for manufacturing a liquid crystal panel, which can restrain the influence of side etching accompanied with etching treatment to the minimum. The etching solution for glass according to the present invention is an etching solution for glass for etching glass, and contains at least an etching inhibitor which reduces the etching rate of glass and contains at least one of an alkali and a fluorine complexing agent. The etching inhibitor preferably adheres to a modified portion of the glass, which is modified to be easily etched, to generate a reaction product that inhibits an etching reaction.

Description

Etching solution for glass and method for producing glass substrate

Technical Field

The present invention relates to an etching solution for glass for cutting or perforating glass, and a method for producing a glass substrate using the etching solution.

Background

As a technique for cutting or perforating glass, there are various techniques. Conventionally, methods such as scribe and break, laser ablation processing, ultrasonic spindle, and wet etching have been used in many cases.

In the case of scribe line breakage in these methods, it is difficult to form a glass panel having a profile with rounded corners. In addition, in laser ablation processing, there are problems that the processing speed is low and contamination due to ablation debris is likely to occur. In the ultrasonic spindle, there is a risk that the strength is reduced by damage after processing, and it is difficult to keep the processed end face at a right angle to the main face in the wet etching process.

Therefore, in the related art, there is a technique of modifying a portion to be cut or a portion to be perforated in glass by laser using both a laser technique and an etching technique and then performing a wet etching treatment on the modified portion (for example, see patent document 1). In such a technique, the etching rate of the modified portion in the glass is about 3 to 5 times faster than that of other portions, and as a result, the glass can be cut or perforated appropriately.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-124752

Disclosure of Invention

Problems to be solved by the invention

However, in the above-described conventional technique, due to the property (isotropy) that etching progresses in the vertical direction and the horizontal direction in the same manner, a cut surface or a through hole having a desired shape may not be obtained. For example, in the cut surface, the central portion in the thickness direction is often convex. In many of the through-holes, the inner diameter of the central portion in the thickness direction distant from both the main surfaces is smaller than the opening diameter in the vicinity of both the main surfaces, and the central portion in the thickness direction has a narrowed portion in cross section.

The invention aims to provide an etching solution for glass and a method for manufacturing a glass substrate, wherein the influence of isotropy of wet etching can be minimized.

Means for solving the problems

The etching solution for glass according to the present invention is used for etching glass (particularly, a portion modified by laser processing so that etching is easily advanced). The etching liquid for glass contains at least an etching inhibitor which reduces the etching rate of glass and contains at least one of an alkali and a fluorine complexing agent.

Examples of the etching inhibitor include bases such as ammonium hydroxide, sodium hydroxide, and potassium hydroxide, and fluorine complexing agents such as titanium oxide, aluminum chloride, boric acid, and silicon dioxide.

The presence of such an etching inhibitor can prevent active species contributing to etching of glass, such as hydrofluoric acid, from being consumed in the vicinity of the main surface of the glass substrate. Further, the compound of the active species and the etching inhibitor (for example, fluorine complex or the like) may emit the active species after moving to a position away from the main surface of the glass substrate, and as a result, the active species may easily reach the position away from the main surface of the glass substrate. Therefore, etching in the direction perpendicular to the main surface of the glass substrate (for example, in the thickness direction and the depth direction) is facilitated, and etching in the direction parallel to the main surface (for example, in the width direction) can be suppressed to the minimum.

In the etching solution for glass, it is preferable that the etching inhibitor is attached to a modified portion of the glass, which is modified to be easily etched, to generate a reaction product inhibiting an etching reaction.

It is presumed that the etching solution containing the etching inhibitor is more likely to cause adhesion of a reaction inhibitor product (fence) to the cut surface or the inner wall of the through hole than a conventional etching solution composed of hydrofluoric acid and a strong acid. Therefore, it is considered that the reaction in the direction parallel to the main surface of the glass substrate (for example, the width direction) is suppressed, and the etching is easily advanced only in the direction perpendicular to the main surface of the glass substrate (for example, the thickness direction and the depth direction). In fact, in the experiments conducted by the applicant, anisotropic etching was also realized in which the influence of isotropy of wet etching was minimized.

In addition, the method for producing a glass substrate according to the present invention uses the etching solution for glass. The glass substrate manufacturing method includes at least a modification step and a first etching step. In the modifying step, the predetermined etching position of the glass substrate is modified by irradiating the glass substrate with laser light so as to form a focal line having a relatively high energy density in a thickness direction of the predetermined etching position. In the first etching step, after the modification step, etching is performed on the etching-intended position using an etching solution for glass.

If necessary, it is preferable that the etching apparatus further includes a second etching step of etching the etching target portion with an etching solution containing at least hydrofluoric acid after the first etching step. The second etching step is performed using a normal etching solution (for example, hydrofluoric acid + hydrochloric acid + remaining water) that does not initially contain the above-described etching-inhibiting substance. Since the etching rate of such an etching solution increases as the concentration of hydrofluoric acid increases, the etching treatment can be shortened as necessary.

Effects of the invention

According to the present invention, the influence of isotropy of wet etching can be minimized.

Drawings

Fig. 1 is a diagram showing a schematic configuration of a liquid crystal panel according to an embodiment of the present invention.

Fig. 2 is a view showing a schematic structure of a multi-surface glass base material including a plurality of liquid crystal panels.

Fig. 3 is a diagram illustrating steps included in one embodiment of a method for manufacturing a liquid crystal panel.

Fig. 4 is a diagram illustrating steps included in one embodiment of a method for manufacturing a liquid crystal panel.

Fig. 5 is a diagram illustrating steps included in one embodiment of a method for manufacturing a liquid crystal panel.

FIG. 6 is a view showing an example of an etching apparatus applied to the present invention.

Fig. 7 is a diagram showing a modification of the etching process applied to the present invention.

FIG. 8 is a schematic view showing a process of breaking a scribe line for cutting a plurality of glass base materials.

FIG. 9 is a schematic view showing a plurality of glass base materials for cutting in a state after division.

Fig. 10 is a diagram showing a characteristic of the structure of the liquid crystal panel.

Fig. 11 is a diagram illustrating a modification procedure related to the piercing process.

Fig. 12 is a diagram illustrating a modification step and an etching step involved in the punching process.

Fig. 13 is a diagram showing a configuration example of an apparatus used in an etching step relating to a piercing process.

Fig. 14 is a diagram illustrating a modification procedure related to the piercing process.

Fig. 15 is a schematic diagram for explaining the influence of the etching stopper.

Fig. 16 is a schematic diagram for explaining the influence of the etching stopper.

Detailed Description

Hereinafter, an embodiment of a method for manufacturing a liquid crystal panel according to the present invention will be described with reference to the drawings. Fig. 1 (a) shows a schematic configuration of a liquid crystal panel 10 according to an embodiment of the present invention. As shown in the figure, the liquid crystal panel 10 is configured such that an array substrate 12 and a color filter substrate 14 are bonded to each other with an intermediate layer such as a liquid crystal layer interposed therebetween. The structures of the array substrate 12 and the color filter substrate 14 may be the same as those of known structures, and therefore, the description thereof is omitted here.

The array substrate 12 has an electrode terminal portion 122 provided so as to extend from a region bonded to the color filter substrate 14. A plurality of circuits are connected to the electrode terminal portion 122, and the liquid crystal panel 10 and the circuits are housed in a housing, thereby constituting, for example, a smartphone 100 shown in fig. 1 (B).

Next, an example of a method for manufacturing the liquid crystal panel 10 will be described. As shown in fig. 2 (a) and 2 (B), the liquid crystal panel 10 is usually manufactured as a multi-surface-pattern-cut glass base material 50 including a plurality of the liquid crystal panels 10. Then, the multiple-piece glass base material 50 is divided to obtain individual liquid crystal panels 10.

In this embodiment, for convenience, a description will be given of a process of cutting out the multi-surface glass base material 50 in which 6 liquid crystal panels 10 are arranged in a matrix of 3 rows and 2 columns and a transparent thin film (a transparent conductive film such as an ITO film or an organic conductive film, or a transparent protective film) 17 is formed on the surface thereof. However, the number of liquid crystal panels 10 included in the multi-surface glass base material 50 is not limited to this, and may be increased or decreased as appropriate.

First, as shown in fig. 3 a and 3B, the multi-surface glass base material 50 is cut along a predetermined line corresponding to the shape (contour) of the liquid crystal panel 10 to form a modified line 20. The modified wire 20 is, for example, a thin wire array in which a plurality of thin wire layers are arranged by a beam pulse (beam diameter is about 1 to 5 μm) irradiated from a pulse laser such as a picosecond laser or a femtosecond laser (see fig. 4 a and 4B). For example, as shown in fig. 4 (a) and 4 (B), the modified thread 20 is a perforated thread having a plurality of through holes or modified layers. The modified line 20 has a property of being etched more easily than other portions of the multi-surface glass base material 50. Of course, the shape of the modified line 20 is not limited to this shape, and may be a shape other than this shape.

When the array substrate 12, the color filter substrate 14, and the transparent film 17 are simultaneously processed with one laser beam, there is a possibility that a defect may occur in the liquid crystal layer. Therefore, in the present embodiment, the occurrence of such a problem can be suppressed by using the laser processing as shown in fig. 3 (C) and 3 (D). That is, as shown in fig. 3 (C), it is preferable that the focal point adjustment and the intensity adjustment are performed so that the modified line 20 is formed only on the array substrate 12, and then the laser light is irradiated from the array substrate 12 side, so that energy is not easily transmitted to the vicinity of the liquid crystal layer. In this state, if the cutting of the multiple-block glass base material 50 can be performed by applying a physical action or a thermal action, the laser processing is terminated.

On the other hand, in the case where it is difficult to divide and cut the multi-surface glass base material 50 in this state, as shown in fig. 3 (D), it is preferable to perform the focus adjustment and the intensity adjustment so that the laser light is irradiated from the color filter substrate 14 side which is the opposite side only after the modified line 20 is formed on the color filter substrate 14. By performing the processing shown in fig. 3 (D), although the number of steps of laser processing increases, the division of the multi-surface glass base material 50 can be easily performed while suppressing the occurrence of defects in the liquid crystal layer.

The beam from the picosecond laser is preferably adjusted to the condensing area appropriately. For example, by adjusting the laser light condensing region so as not to reach the intermediate layer, it is possible to prevent the terminal wiring from being corroded by excessive penetration of an etching solution during the etching treatment.

After the reformed line 20 is formed along the planned shape cutting line in the multi-surface glass base material 50, the multi-surface glass base material 50 is attached with the etching resistant thin film 16 having etching resistance on both main surfaces as shown in fig. 5 (a) and 5 (B). The etching-resistant film 16 is made of polyethylene having a thickness of 50 to 75 μm. However, the structure of the etching resist film 16 is not limited thereto. For example, a film such as polypropylene, polyvinyl chloride, or olefin resin may be appropriately selected and used as long as it has resistance to an etching solution for etching glass.

After the adhesion of the etching resist film 16 is completed, as shown in fig. 5 (C), laser beam irradiation is performed on the etching resist film 16 along the planned shape cutting line corresponding to the shape of the liquid crystal panel 10 to be cut. By the irradiation of the laser beam, the etching resist film 16 is removed along the line to cut the shape. Then, the opening of the etching resist film 16 is formed along the shape-cutting line, and as a result, the forming position of the reformed line 20 of the multi-surface glass base material 50 is exposed to the outside, similarly to the configuration shown in fig. 3 (C).

When the laser processing is completed, as shown in fig. 6, the multi-surface glass base material 50 is introduced into an etching apparatus 300, and a first etching step using an etching solution containing hydrofluoric acid and an etching inhibitor is performed, and a second etching step (optional treatment) using a normal etching solution containing hydrofluoric acid, hydrochloric acid, or the like is performed as necessary. An etching solution containing about 1 to 10 wt% of hydrofluoric acid and about 5 to 20 wt% of hydrochloric acid is usually used, and a surfactant or the like is appropriately used in combination as needed, but in the first etching step, the etching solution usually further contains an etching inhibitor.

Examples of the etching inhibitor include bases such as ammonium hydroxide, sodium hydroxide, and potassium hydroxide, and fluorine complexing agents such as titanium oxide, aluminum chloride, boric acid, and silicon dioxide. The etching inhibitor acts to reduce the etching rate (etching rate) of the etching solution mainly composed of hydrofluoric acid and a strong acid. In general, the hydrofluoric acid concentration or the fluorine concentration has a positive correlation with the etching rate, and the etching rate becomes faster as the hydrofluoric acid concentration or the fluorine concentration increases.

However, the applicant speculates that by including an etching inhibitor in an amount of about 0.05 to 5.00 molar equivalents relative to the amount of hydrofluoric acid, the etching rate can be suppressed to as low as about 0.01 to 3.00 μm/min even if the concentration of hydrofluoric acid or the concentration of fluorine is increased, and by forming such a state, anisotropic etching is realized in which the influence of isotropy of wet etching is minimized.

As the compound of hydrofluoric acid and an etching inhibitor, there can be mentioned, as an example of a substance which can suitably realize anisotropic etching up to now, fluorinated titanic acid (H)₂TiF₆) Ammonium fluoride (NH)₄F) Tetrafluoroboric acid (HBF)₄) Hexafluorophosphoric acid (HPF)₆) Hexafluorosilicic acid (H)₂SiF₆) Hexafluoroaluminic acid (H)₃AlF₆) Hexafluoroantimonic acid (HSbF)₆) Hexafluoroarsenic acid (HAsF)₆) Hexafluorozirconic acid (H)₂ZrF₆) Beryllium tetrafluoride acid (H)₂BeF₄) Heptafluorotantalic acid (H)₂TaF₇) Etc. orSalts thereof.

In the etching apparatus 300, the multi-surface glass base material 50 is conveyed by the conveying rollers, and the etching solution is brought into contact with one surface or both surfaces of the multi-surface glass base material 50 in the etching chamber, thereby etching the multi-surface glass base material 50. Further, since a cleaning chamber for washing the etching solution adhering to the multi-surface glass base material 50 is provided at the rear stage of the etching chamber in the etching apparatus 300, the multi-surface glass base material 50 is discharged from the etching apparatus 300 in a state where the etching solution is removed.

As an example of a method of bringing the etching liquid into contact with the multi-surface glass base material 50, as shown in fig. 7 (a), spray etching in which the etching liquid is sprayed to the multi-surface glass base material 50 in each etching chamber 302 of the etching apparatus 300 is exemplified. Alternatively, instead of the shower etching, as shown in fig. 7 (B), a configuration may be adopted in which the split glass base materials 50 are conveyed in a flooded etching chamber 304 while being in contact with the overflowing etching liquid.

As shown in fig. 7 (C), immersion etching may be employed in which one or a plurality of cut glass base materials 50 stored in a carrier are immersed in an etching bath 306 containing an etching solution.

In either case, it is important that: in the etching process, the planned shape cutting line is prevented from penetrating in the thickness direction and cutting the plurality of cut glass base materials 50. Therefore, in the etching process (particularly, in the latter half of the etching process), it is necessary to slow down the etching rate and accurately control the etching amount.

The time of the etching process can be shortened if a fast etching rate is used initially and the etching rate is slowed down in stages rather than in the whole etching process. For example, the following structure is preferably employed: the concentration of hydrofluoric acid in the etching solution decreases as the etching apparatus 300 moves to the subsequent stage.

When the cut multi-surface glass base material 50 passes through the etching apparatus 300, the modified wire 20 is etched. In the modified line 20, the etching solution penetrates faster than other portions, and the glass dissolves along the line, thereby facilitating the cutting of the color filter substrate by the modified line 20. In addition, when a flaw or the like is generated during laser irradiation, the flaw is also easily eliminated.

After the etching process is completed, the adhered etching resist film 16 is peeled off. Next, as shown in fig. 8 (a) to 8 (C), the multi-surface glass base material 50 is cut and processed to form the terminal-section-cut grooves 30 for removing the regions of the color filter substrate 14 that face the electrode terminal sections 122 of the array substrate 12. In this embodiment, the terminal portion cut groove 30 is formed inside the region of the color filter substrate 14 facing the electrode terminal portion 122 of the array substrate 12 by a scribing wheel (wheel cutter) 250. The terminal portion cutting groove 30 is formed along the predetermined terminal portion cutting line to remove a region of the color filter substrate 14 facing the electrode terminal portion 122 of the array substrate 12.

When the formation of the terminal-portion-cutting groove 30 by the scribing wheel 250 is completed, the process proceeds to the cutting of the multiple glass base materials 50 and the removal of the region facing the electrode terminal portion 122. In the multi-surface glass base material 50 to be cut, the modifying line 20 is formed by laser thinning, and the modifying line is further etched, whereby the multi-surface glass base material 50 can be cut at the modifying line 20 by only a slight mechanical pressure. For example, by applying a slight pressing force or a slight stretching force to the multi-surface glass base material 50 or applying a slight ultrasonic vibration, the multi-surface glass base material 50 can be divided without being stained as shown in fig. 9.

First, since the liquid crystal panel is not completely cut by the etching process, it is possible to prevent the end faces of the liquid crystal panel 10 separated in the etching process from colliding with each other and being damaged. Further, the multi-surface cutting glass base material 50 in a state of not being completely cut after the etching treatment may be directly conveyed (a large size state is maintained). Further, since the etching solution does not reach the electrode terminal portion, it is not necessary to protect the electrode terminal portion with a masking agent having etching resistance. Further, since the etching process is performed at least in the center portion of the end face of the liquid crystal panel 10, the strength (for example, bending strength) of the liquid crystal panel becomes higher than the case of cutting only by laser processing.

Fig. 10 (a) to 10 (C) show a schematic configuration of the divided liquid crystal panel 10. As shown in the figure, the end face of the liquid crystal panel 10 is substantially perpendicular to the main surface. That is, the taper widths (L1 to L4 in fig. 10C) generated at the end surfaces of the thick plate array substrate 12 and the color filter substrate 14 can be suppressed to substantially zero (specifically, 30 μm or less).

Since the liquid crystal panel 10 is manufactured in this manner, the influence of the side etching hardly occurs, and the multi-surface glass base material 50 for cutting can be designed so that the liquid crystal panels 10 are arranged close to each other. On the other hand, by decreasing the ratio of the treatment (first etching step) with the etching solution containing the etching inhibitor and increasing the ratio of the treatment (second etching step) with the etching solution containing hydrofluoric acid, hydrochloric acid, or the like, the values of the taper widths L1 to L4 can be increased. The ratio of the treatment with the etching solution containing the etching inhibitor is preferably adjusted in consideration of the shape of the end face required and the etching rate required.

Next, another embodiment of the through-hole processing will be described with reference to fig. 11 to 14. Fig. 11 shows one step of processing a glass substrate 510 for manufacturing a glass interposer having a plurality of through holes. In this embodiment, at least the modification step and the etching step are performed on the glass substrate 510 when manufacturing the glass interposer.

The type of the glass substrate 510 is not particularly limited as long as it is glass, but when it is used for a package of a semiconductor device such as a glass interposer, alkali-free glass is preferable. This is because, in the case of alkali-containing glass, there is a possibility that an alkali component in the glass precipitates and adversely affects the semiconductor element. The thickness of the glass substrate 510 is not particularly limited, and the glass substrate 10 can be appropriately processed to have a thickness of 0.1mm to 2.0mm, for example.

In the modification step, the laser heads 512 irradiate the predetermined positions for forming the plurality of through holes in the glass substrate 510 with laser light. The irradiated laser light passes through an optical system unit 514 for forming a focal line having a relatively high energy density in the thickness direction of the glass substrate 510.

The optical system unit 514 is constituted by a single or a plurality of optical elements (lenses and the like), and is configured to focus the laser beam from the laser head 512 into a focal line of the laser beam having a length within a predetermined range in the thickness direction of the glass substrate 510.

Therefore, by irradiating the glass substrate 510 with the laser beam, the through-hole formation-scheduled position in the glass substrate 510 is modified over the entire region in the thickness direction, for example, a void-like modified portion 102 is formed. In order to form a plurality of modifying portions 102 on the glass substrate 510, a stage for moving the glass substrate 510 on the XY plane may be used, and a laser processing apparatus including the laser head 512 and the optical system unit 514 may be provided with a driving mechanism for moving these components in the XY direction.

The type and irradiation conditions of the laser are not limited as long as the laser can modify the intended position of the through hole of the glass substrate 510 to be easily etched. In the present embodiment, laser beams oscillated from a short pulse laser (for example, picosecond laser or femtosecond laser) are irradiated from the laser head 512, but for example, CO may be used₂Lasers, UV lasers, etc. In the present embodiment, the output is controlled so that the average laser energy of the laser beam is about 30 μ J to 300 μ J.

After the modification step, the modified portion formed at the predetermined position of the through hole of the glass substrate 510 is etched to dissolve the modified portion 102, thereby forming a through hole at the predetermined position of the through hole.

The reforming step and the subsequent etching step will be described with reference to fig. 12 (a) to 12 (C). Fig. 12 (a) shows the modification step described above. The laser beam emitted from the laser head 512 is condensed at a predetermined position of the through hole formed in the glass substrate 510 by the optical system unit 514, and a focal line is formed in the thickness direction of the predetermined position of the through hole. The optical system unit 514 includes at least a diffusion lens for diffusing the laser light, a condensing lens for condensing the laser light, and the like, and can condense the laser light to form images at a plurality of points on the focal line, for example.

As a result, as shown in fig. 12 (B), the reformed portion 102 is formed in the entire region in the thickness direction at the predetermined position in the through-hole formation of the glass substrate 10. The modified portion 102 exhibits a property of being more easily etched than other portions by receiving energy from the laser. When the etching solution is brought into contact with the modified part 102, the modified part 102 is dissolved, and as a result, as shown in fig. 12 (C), a through hole 104 is formed at a predetermined position of the through hole.

In the etching step, as shown in fig. 13 (a), the glass substrate 510 is introduced into an etching apparatus 520, and is subjected to etching treatment using an etching solution containing hydrofluoric acid, hydrochloric acid, or the like. In the etching apparatus 520, while the glass substrate 510 is conveyed by the conveying rollers, the etching solution is brought into contact with one surface or both surfaces of the glass substrate 510 in the etching chamber 522, thereby performing etching processing on the glass substrate 510.

Here, as shown in fig. 13 (B), the glass substrate 510 is subjected to shower etching in which an etching solution is sprayed into each etching chamber 522 of the etching apparatus 520. As the etching solution, for example, an etching solution containing 1 to 10 wt% of hydrofluoric acid, 5 to 20 wt% of hydrochloric acid and the etching inhibitor can be used. In addition, since a cleaning chamber for washing away the etching solution adhering to the glass substrate 510 is provided at the rear stage of the etching chamber 520 in the etching apparatus 520, the glass substrate 510 is discharged from the etching apparatus 520 with the etching solution removed.

In addition to the method of spraying the etching solution, the etching solution may be brought into contact with the glass substrate 10 by immersing the glass substrate 510 in the etching solution. However, from the viewpoint of allowing the etching solution to penetrate into the fine through-holes, the systems shown in fig. 13 (a) and 13 (B) are preferably used in which the etching solution is sprayed.

When the etching solution is sprayed onto the glass substrate 510 with a sufficient pressure, the modified portion 102 of the glass substrate 510 is normally dissolved appropriately, and the through hole 104 is formed in the glass substrate 510 as shown in fig. 12 (C). In the present embodiment, the discharge pressure at the time of spraying is, for example, 0.05Mpa to 0.10Mpa, and preferable results are obtained when the treatment is performed with the amount of the etching liquid discharged from each spray nozzle being about 1.25 to 2.50 l/min.

In the conventional treatment with an etching solution, a through-hole 105 having a narrowed portion in the central portion may be formed as shown in fig. 14 (a) depending on the spray pressure, concentration, viscosity of the etching solution, or the size of the modified portion 102. Such a through hole 105 is not preferable because it may cause a failure such as conduction failure when used for an interposer.

In the present embodiment, by appropriately using an etching solution containing an etching inhibitor, as shown in fig. 14 (B), a narrowed portion is less likely to be formed in the central portion of the glass substrate 510 in the thickness direction.

By using an etching solution containing an etching inhibitor in this way, the influence of side etching due to isotropy of wet etching hardly occurs, and thus a through hole without a narrow portion can be formed. On the other hand, the shape of the narrowing portion can be adjusted by decreasing the ratio of the treatment (first etching step) with the etching solution containing the etching inhibitor and increasing the ratio of the treatment (second etching step) with the normal etching solution. The ratio of the first etching step to the second etching step is preferably adjusted in consideration of the shape of the through hole required and the etching rate required. As described above, since the second etching step is an arbitrary process, the ratio can be made zero.

The through-hole formed by the above method is subjected to spray etching to reduce or eliminate the microcracks. Therefore, there is an advantage that not only the shape of the through hole can be appropriately maintained, but also the strength of the glass interposer can be maintained. Here, although an example in which the glass substrate 510 is used as a glass interposer is described, the use of the glass substrate 510 is not limited thereto. For example, it can be applied to MEMS packaging or a microchip device for life science.

Here, the mechanism of anisotropic etching in the above embodiment will be described with reference to fig. 15. As shown in this figure, in a chemical equilibrium state, the fluorine complex (here, titanium fluorotitanate) is likely to release hydrofluoric acid as an active species at a position away from the main surface of the glass substrate as hydrofluoric acid is consumed by etching treatment. As a result, the hydrofluoric acid easily reaches a position away from the main surface of the glass substrate. Therefore, etching in a direction perpendicular to the main surface of the glass substrate (for example, in the thickness direction and the depth direction) is easily advanced.

If hydrofluoric acid is continuously consumed in the vicinity of the main surface of the glass substrate, etching proceeds in a direction parallel to the main surface of the glass (for example, in the width direction), and the influence of isotropic etching is likely to occur.

Next, the operation and effect of the etching solution for glass containing an etching inhibitor according to the embodiment of the present invention will be described using practical examples. First, an experimental method for verifying the action and effect of the etching liquid for glass will be described with reference to fig. 16 (a) to 16 (D). As shown in fig. 16 (a), before the etching treatment, first, output control is performed so that the average laser energy of the laser beam is about 250 μ J, and then, reformed holes are formed in a glass substrate having a thickness of about 200 μm.

Next, etching treatment was performed for about 40 minutes using an etching solution (40 ℃ C.) having a composition shown in Table 1 below. Fig. 16 (B) shows a glass substrate etched with the etching solution according to the comparative example, and fig. 16 (C) shows a glass substrate etched with the etching solution according to each example.

[ Table 1]

The etching solution of comparative example 1 was adjusted to have an etching rate of about 1.0. mu.m, and contained hydrofluoric acid at a concentration of 0.90 mol/L.

On the other hand, examples 1 to 6 are etching solutions in which ammonium hydroxide, potassium hydroxide, sodium hydroxide, silica, boric acid, and aluminum chloride were added to hydrofluoric acid as etching inhibitors, respectively. Since the etching rate decreases when these etching inhibitors are added, the hydrofluoric acid concentration is higher than that of the etching solution of comparative example 1 so that the etching rate becomes about 1.0 μm/min.

After the etching treatment, as shown in fig. 16 (D), the width of the formed hole (W0 in the case of the comparative example, W1 in the case of the example) and the depth D of the hole were measured, and the value of the depth D divided by the value of the width (W0 or W1) was taken as "degree of anisotropy". It can be said that the larger the value of the degree of anisotropy, the more anisotropic etching is achieved. The measurement of the glass substrate after etching was performed using an optical microscope.

As shown in Table 1, the degree of anisotropy obtained by using the etching solution of comparative example 1 was 3.1. In general, in the case of isotropic etching, the degree of anisotropy is 1, but here, since modified pores are formed by laser processing, the degree of anisotropy greatly exceeding 1 can be obtained without adding an etching-inhibiting substance.

The degrees of anisotropy obtained from the etching solutions of examples 1 to 6, to which the etching inhibitor was added, were higher than the degree of anisotropy obtained from the etching solution of comparative example 1. This shows that the anisotropic etching is further realized by the etching stopper.

Here, table 2 is used to explain other experimental results.

[ Table 2]

The etching solution of comparative example 2 was adjusted to have a hydrofluoric acid concentration of 0.10 mol/L. The etching solutions of examples 7 to 12 were prepared by adding 0.10 molar equivalent of an etching inhibitor (ammonium hydroxide, potassium hydroxide, sodium hydroxide, silicon dioxide, boric acid, and aluminum chloride) to the amount of hydrofluoric acid.

As shown in Table 2, the degree of anisotropy obtained by using the etching solution of comparative example 2 was 3.0. On the other hand, the degrees of anisotropy obtained from the etching solutions of examples 7 to 12, to which the etching inhibitors were added, were higher than the degree of anisotropy obtained from the etching solution of comparative example 2 (maximum 6.8). As is clear from the experimental results shown in table 2, the etching inhibitor further realizes anisotropic etching.

The above description of embodiments is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the scope of the claims. Further, the scope of the present invention is intended to include all changes within the meaning and range equivalent to the scope of the appended claims.

Description of the symbols

10-liquid crystal panel

12-array substrate

14-colour filter substrate

16-etching-resistant film

17-transparent film

20-modified wire

30-terminal part cutting groove

50-cutting a glass base material for multiple blocks

100-smart phone

122-electrode terminal part

250-scribing wheel

300-etching apparatus

302. 304-etching chamber

306-etching a trench.

Claims

1. An etching solution for glass, which is used for etching glass,

the etching liquid for glass contains at least an etching inhibitor which reduces the etching rate of glass and contains at least either an alkali or a fluorine complexing agent.

2. The etching solution for glass according to claim 1, wherein,

the etching inhibitor is attached to a modified portion of the glass, which is modified to be easily etched, to generate a reaction product that inhibits an etching reaction.

3. A method for producing a glass substrate using the etching solution for glass according to claim 1 or 2, wherein,

the glass substrate manufacturing method includes:

a modification step of modifying a predetermined etching position of a glass substrate by irradiating the glass substrate with laser light so as to form a focal line having a relatively high energy density in a thickness direction of the predetermined etching position; and

and a first etching step of etching the etching target position with the etching solution for glass after the modification step.

4. The glass substrate manufacturing method according to claim 3,

the method for manufacturing a glass substrate further includes a second etching step of etching the etching target position with an etching solution containing at least hydrofluoric acid after the first etching step.