JP4849890B2 - Glass component having through hole and method for manufacturing the same - Google Patents

Description

  The present invention relates to a glass component having a through hole having a uniform and fine diameter and a method for manufacturing the same.

  In recent years, glass substrates or glass parts having fine through-holes are being applied to printed wiring boards, inkjet printing heads, gas flow meters, etc., especially those using photosensitive glass as the glass material. Has been. As a method for forming a through hole in photosensitive glass, for example, methods disclosed in Patent Document 1 and Patent Document 2 are known.

  FIG. 8 is an explanatory diagram of a method for manufacturing a glass component having a through hole disclosed in Patent Document 1. Hereinafter, the manufacturing method of the glass component which has a through-hole disclosed by patent document 1 is demonstrated, referring FIG. FIG. 8 is a process flow chart of a process of forming a through hole in a photosensitive glass having a substrate shape, and a side sectional view schematically showing a state in each process. In the figure, reference numeral 100 denotes photosensitive glass, 101a denotes an exposure crystallization portion, 101 denotes a through hole, 102 denotes a photomask, 102a denotes a light shielding film of the photomask, and 103 denotes collimated ultraviolet light. The light shielding film 102a is formed on the photomask 102 as a pattern corresponding to the desired shape and arrangement of the through holes.

  First, as shown in FIG. 8A, a photomask is placed on the photosensitive glass 100 and irradiated with collimated ultraviolet light 103. By this ultraviolet light irradiation, an exposed crystallized portion 101a is formed as a latent image in the photosensitive glass 100. As shown in FIG. 8A, the latent image pattern corresponds to the negative pattern of the light shielding film 102a pattern of the photomask. After the heat treatment of the photosensitive glass 100 on which the latent image is formed, the exposed crystallization portion 101a, that is, the region where the so-called latent image is formed is removed by etching with a hydrofluoric acid solution, as shown in FIG. 8B. A desired through-hole pattern is obtained.

Moreover, the method disclosed in Patent Document 2 is a method in which the method disclosed in Patent Document 1 and the through hole forming method by laser processing are used in combination. That is, a through-hole smaller than a desired through-hole diameter is formed in advance by a laser processing method, and then the through-hole is formed through the latent image formation, heat treatment, and etching steps described above. The through holes formed in advance serve to improve the circulation of the etching solution in the through holes when etching is performed after the heat treatment.
JP 2001-44639 A JP 2001-105398 A

  By the way, the technical trend of increasing the density of printed wiring boards or increasing the definition of printed images is unknown, and in response to this, the demand for glass parts having fine through-holes has become stronger. However, as described above, the conventional method for forming a through hole in a photosensitive glass is a pattern forming method that uses a photomask having a pattern corresponding to a desired through hole shape or arrangement, and follows the photolithographic technique. In terms of miniaturization of the through-holes, it was not possible to cope with it sufficiently.

  FIG. 6 is an explanatory view of a latent image forming process by ultraviolet exposure using a conventional photomask. FIG. 6A is a schematic cross-sectional view schematically showing how a latent image is formed by ultraviolet exposure. In the figure, reference numeral 102b denotes a photomask opening, and 81 denotes a region where a latent image is formed. , AA ′ is a line indicating the surface position of the photosensitive glass 100, BB ′ and CC ′ are lines indicating arbitrary positions inside the substrate, and CC ′ is more from the photomask 102 than BB ′. Located in a remote location. The parts with other numbers are as described above. FIG. 6A shows a so-called contact exposure method in which exposure is performed in a state where the photomask 102 and the photosensitive glass are in close contact with each other.

  FIGS. 6B to 6D are schematic distribution curves showing exposure dose distributions in directions along the lines AA ′, BB ′, and CC ′. The horizontal axis represents distance, and the vertical axis represents Represents exposure. Here, the origin O is a position corresponding to the center of the opening 102b in the photomask. As the ultraviolet light (not shown) transmitted through the opening travels through the photosensitive glass substrate, it oozes out to a portion corresponding to the light shielding film 102a, and as a result, reaches a portion covered with the light shielding film 102a. (Hereinafter, the phenomenon that light begins to bleed out is referred to as “bleeding effect”). FIG. 6B to FIG. 6D schematically show this state.

  FIG. 6B is an exposure amount distribution on the surface of the photosensitive glass 100 (AA ′ line). As described above, since the photomask 102 and the photosensitive glass 100 are in close contact with each other, the exposure amount distribution on the surface is represented by a box function. In this case, the width of the exposure amount distribution is equal to the width of the opening 102b, and the portion corresponding to the region immediately below the light shielding film 102a is not exposed. At the BB ′ position away from the photomask, as shown in FIG. 6C, the exposure width is widened due to the light bleeding effect, and the exposure amount is absorbed by the light absorption in the photosensitive glass substrate. Decays. This situation becomes more prominent at the position CC ′ as shown in FIG.

  FIG. 7 is a diagram schematically showing holes formed when a latent image forming region is removed by etching through a heat treatment after forming a latent image. FIG. 7 is a schematic side sectional view showing the shape after etching removal, and reference numeral 91 is a hole. In general, etching proceeds from the surface of the substrate. Further, the etching speed of the portion where the latent image is not formed is smaller than the speed of the area where the latent image is formed, but is not completely zero and is eroded by the etching solution. The etching rate of the portion where the latent image is not formed is about 1/50 of that of the latent image forming portion. From this, as the etching of the latent image forming region progresses, the planar etching on the surface of the photosensitive glass also proceeds, and as a result, as shown in FIG. It will be distributed in the direction.

  Thus, in the through hole forming process to which the conventional exposure method is applied, the diameter of the through hole depends on both the diameter of the opening in the photomask and the light bleeding effect. Of course, if the opening diameter of the photomask is reduced, the minimum value of the through-hole obtained is also reduced. However, as will be described below, as the through hole diameter decreases, the uniformity in the depth direction is relatively impaired. The light bleeding effect is determined by factors such as the parallelism of the light to be irradiated, the light diffraction effect, or scattering within the photosensitive glass 100. These factors are almost independent of the size of the opening 102b of the photomask, in other words, the diameter of the through hole. That is, when the through-hole diameter is sufficiently large, the ratio between the through-hole diameter and the amount of enlargement of the through-hole diameter due to the light bleeding effect, or the ratio between the through-hole diameter and the lack of uniformity of the through-hole diameter is small. . Therefore, when the through-hole diameter is sufficiently large, these fluctuations of the through-hole diameter due to the light oozing effect are values that can be ignored. However, the ratio increases as the through-hole diameter decreases, and as a result, formation of a through-hole having a uniform diameter becomes extremely difficult.

  As described above, in the above-described conventional method, it is extremely difficult to form a through hole having a uniform diameter in the depth direction of the through hole due to the diffraction effect of light as the through hole diameter decreases. Of course, when the depth of the through hole is shallow, that is, when the thickness of the photosensitive glass substrate is thin, a through hole having a diameter of several μm can be easily formed. Is about several tens of μm. In such a situation, a decrease in mechanical durability of the glass component having a through hole is inevitable, and its application is extremely limited. For example, when the substrate thickness is 350 μm, which can ensure mechanical strength, in other words, when the depth of the through hole is 350 μm, the diameter is about 30 μm or less and the aspect ratio (through hole In other words, it is extremely difficult to form a through hole having a diameter of about 12 or more and a uniform diameter in the depth direction. The present invention has been made in view of the above problems, and a glass component having a photosensitive glass substrate as a base material, a high aspect ratio, and a uniform fine through-hole having a diameter of 30 μm or less, and the glass component. The object is to provide a manufacturing method.

The glass component provided by the present invention is:
In a glass part having a through hole, the base of the glass part is made of photosensitive glass, and the diameter of the through hole is substantially constant regardless of the part of the through hole. The length (L) of the through hole and the through hole A glass part having a through hole, wherein the ratio (L / d) to the diameter (d) is 15 or more and the diameter (d) is 30 μm or less.
The glass component provided by the present invention is
The photosensitive glass contains 0.001 to 0.05% by weight of Au, 0.001 to 0.5% by weight of Ag, 0.001 to 1% by weight of Cu ₂ O, 0.001 as a photosensitive material. A glass characterized in that it is a photosensitive glass containing at least one of Pt of 0.1 wt% and further containing 0.001 to 0.2 wt% of CeO ₂ as a photosensitizer. It is a part.
The first means for manufacturing the glass part is:
The first step of forming a latent image by irradiating the portion of the photosensitive glass substrate where the through-hole is formed with a condensed light beam, the latent image is formed by heat-treating the photosensitive glass irradiated with the condensed light beam in the first step. A glass part having a through hole, comprising: a second step of crystallizing the formed portion; and a third step of forming a through hole by dissolving and removing the portion crystallized in the second step It is a manufacturing method.
The second means is a method of manufacturing a glass part having a through-hole according to the first means. When the condensed light beam is irradiated in the first step, the beam waist of the condensed light beam is the photosensitive glass. It is a manufacturing method of the glass component which has a through-hole characterized by being located inside.
The third means is
In the method for manufacturing a glass part having a through hole according to the first means, when the condensed light beam is irradiated in the first step, the position of the beam waist of the condensed light beam is along the optical axis of the condensed light beam. A method of manufacturing a glass component having a through hole, wherein the condensed light beam is irradiated continuously or intermittently while moving within the photosensitive glass substrate intermittently or continuously.

  In the method of forming a through hole in a photosensitive glass, when a latent image is formed by light irradiation and a method in which a portion where the latent image is formed is basically removed, the diameter, aspect ratio, or depth of the through hole is determined. The shape of the through-hole, such as the uniformity of direction, depends on both condition factors of the latent image formation process and the etching removal process, and in some cases, the influence of the latter is considered to be greater than the former. . As a result of intensive studies on both of the factors described above, the present inventors determined that the minimum value of the through-hole diameter that can be realized when forming a fine through-hole is that the factors of the latent image forming step described above are determined. The inventors have found that it is more dominant than various factors in the etching removal process, and have completed the present invention based on the result. According to the present invention, it is possible to form a through hole having a uniform and fine hole diameter and a high aspect ratio (the ratio is 15 or more) in the photosensitive glass, and the photosensitive glass having the through hole is used as a substrate. Glass parts can be provided.

  FIG. 1 is an explanatory view of a method for manufacturing a glass component having a through hole according to the first embodiment of the present invention. FIG. 1 (a) is a schematic side sectional view schematically showing the light irradiation state during exposure, and FIG. 1 (b) schematically shows the distribution of exposure amount in each part of the photosensitive glass. It is. In the figure, reference numeral 21 denotes a condensed light beam, 21a denotes a beam waist of the condensed light beam, AA ′ denotes a line indicating a central portion of the substrate-shaped photosensitive glass 100, and BB ′ denotes a position of the surface of the photosensitive glass 100. CC ′ is a line indicating the position of the back surface of the photosensitive glass 100, 22 is an exposure distribution in the direction along the AA ′ line, 23 is the same distribution in the direction along the BB ′, E, R Is the exposure amount and position at the intersection of the exposure distributions 22 and 23. In FIG. 1B, the origin (position where the distance is 0) corresponds to the position corresponding to the intersection of the optical axis of the condensed light beam 21 and the line AA ′ or BB ′, and the horizontal axis represents AA ′ or BB. 'The distance along the line (distance from the origin), the vertical axis indicates the exposure amount.

  An important difference between the present embodiment and the above-described prior art is that a condensed light beam 21 focused by an optical system such as a lens is used without using a photomask at the time of exposure and without using a collimated light beam. There is in point. In general, the exposure amount distribution by the condensed light beam is approximated by a Gaussian distribution. As indicated by reference numeral 22 in FIG. 1, the distribution at the position of the beam waist 21a (corresponding to the line AA ') is the sharpest, and the peak value of the exposure amount is also the maximum. On the other hand, at a position away from the position of the beam waist 21a, for example, at a position corresponding to the substrate surface BB ′ line, the shape is as indicated by reference numeral 23 in FIG. 1B, the distribution width is increased, and the exposure amount is increased. The peak value of also decreases.

  The exposure dose distribution has a point-symmetric relationship with the beam waist position as the center of symmetry. For example, the exposure dose distribution along the CC ′ line is equal to the distribution along the BB ′ line. FIG. 2 shows a latent image formed when the exposure amount E by the condensed light beam 21 in FIG. 1 is set to an exposure critical value necessary for forming a latent image on the photosensitive glass 100 and a penetration formed based on the latent image. It is explanatory drawing of a hole. Here, FIG. 2A shows a state where a latent image after exposure is formed, and FIG. 2B shows a state after the latent image is removed by etching. In the figure, reference numeral 31a denotes a latent image forming area, and 31 denotes a formed through hole.

  As shown in FIG. 1B, the position where the exposure amount is E is the inner central portion of the photosensitive glass along the AA ′ line, the substrate surface portion along the BB ′ line, and the CC ′ line. In the back surface part of the photosensitive glass, all are positions R. From this, as shown in FIG. 2A, a cylindrical latent image region 31a having a uniform radius R in the thickness direction of the photosensitive glass 100 is formed. The photosensitive glass 100 in such a state is heated and heat-treated and then etched to form the through hole 31 having a cross-sectional shape as shown in FIG. As described above, the reason why the diameter of the through hole 31 is enlarged near the front and back surfaces of the photosensitive glass 100 is as the etching of the latent image forming region progresses even in the region where the latent image is not formed. This is because planar etching on the surface of the photosensitive glass 100 also proceeds.

  In this case, if the hole diameter is enlarged, a uniform through-hole diameter can be obtained by removing it by a machining method such as grinding or lapping, or a dry etching method such as ion milling or RIE (Reactive Ion Etching). A glass substrate having the same can be obtained. In this case, strictly speaking, the exposure amount distributions at all positions inside the substrate do not intersect at one point. For example, in FIG. 1A, the exposure dose distribution at a portion located between the AA ′ line and the BB ′ line is a distribution showing an intermediate shape between the exposure dose distributions 22 and 23 in FIG. Thus, the intersection of this distribution and the exposure dose distributions 22 and 23 does not become the distance R in the exposure dose E, but has different values. However, the amount of deviation from the distance R is very small, and a cylindrical latent image having a uniform diameter is formed as shown in FIG. 2B.

  FIG. 3 is an explanatory view of a method for manufacturing a glass component having a through hole according to the second embodiment of the present invention. FIG. 3a is a schematic side cross-sectional view schematically showing the light irradiation state during exposure, and FIG. 3b is a dual view showing the distribution of exposure dose at each part of the photosensitive glass. In the figure, DD ′ is a line indicating a position corresponding to ¼ of the thickness of the photosensitive glass from the surface of the photosensitive glass 100, and EE ′ is 3/4 of the thickness of the photosensitive glass from the surface of the photosensitive glass 100. , 24 is an exposure amount distribution along the DD ′ line, 41a is a latent image forming region, E2 is a peak value of the exposure amount distribution 24, and R2 is an exposure amount E2 in the exposure amount distribution 22. Position.

  Further, the beam waist 21a of the condensed light beam 21 is located on the AA 'line. The latent image forming area 41a is a latent image obtained when E2 is set to a value that matches the critical exposure amount for forming a latent image in the photosensitive glass 100 and is exposed with the exposure amount E2. In this case, the formed latent image forming region 41a has a substantially spheroid shape, and its minor axis coincides with R2. Furthermore, this R2 is smaller than R in the first embodiment. However, in this latent image state, a through hole that is a hole communicating with the front and back surfaces of the substrate cannot be formed.

  Therefore, it is effective to perform exposure of the photosensitive glass by a two-stage process described below. FIG. 4 is an explanatory diagram of the two-stage exposure process, and FIG. 5 is a diagram showing a latent image formed by the two-stage exposure. In the figure, reference numerals 51, 51a and 51b denote latent image forming areas. In FIG. 4a, when the beam waist 21a of the condensed light beam 21 is set to be positioned on the DD ′ line and exposed, FIG. 4b is set and exposed to set the beam waist 21a to be on the EE ′ line. The case is shown schematically. The exposure amount is E2 as in the case described above. That is, the two-stage exposure process is a first-stage exposure process, and as shown in FIG. 4a, a latent image 51 is formed from the surface side of the photosensitive glass 100 to the central portion, and subsequently, FIG. As shown in FIG. 4, the latent image 51b is formed from the center to the bottom of the photosensitive glass 100 in the second exposure process.

  Through the two-stage exposure process described above, as shown in FIG. 5, the photosensitive glass 100 capable of obtaining a continuous latent image forming region from the surface to the bottom of the photosensitive glass is the same as that of the first embodiment. Similarly, by performing heat treatment and etching away the latent image forming region, it is possible to form a through hole having a smaller diameter than in the first embodiment. In the second embodiment, the two-stage exposure process has been described. However, the second embodiment is not limited to the two-stage exposure process, and an exposure process having two or more stages is also possible. That is, in a multi-stage exposure process, the beam position of the condensed light beam can be set at an arbitrary position inside the substrate along the optical axis according to the irradiation exposure amount, and when necessary. It is possible to set the position of the beam waist also outside the substrate. Also, the method of changing the beam waist position can be changed intermittently or continuously.

  In the embodiment of the present invention, either laser light or normal ultraviolet light can be used as the light source. Hereinafter, the present invention will be described in more detail based on examples.

This example is an example of the first embodiment described above. As the photosensitive glass 100, a glass substrate (trade name: PEG3 manufactured by HOYA Corporation) having the following composition and a thickness of 0.5 mm was used.
SiO ₂ : 78.0% by weight
Li ₂ O: 10.0% by weight
AI ₂ O ₃ : 6.0% by weight
K ₂ O: 4.0% by weight
Na ₂ O: 1.0% by weight
ZnO: 1.0% by weight
Au: 0.003% by weight
Ag: 0.08% by weight
CeO: 0.08% by weight

The light source used is a third harmonic of a YAG laser having a wavelength of 355 nm, and when exposing the photosensitive glass substrate using the light, the NA of the condensed light flux is set to 0.4. Used pulsed light (pulse width: about 6 nsec) and controlled the number of times of pulse irradiation to control the integrated exposure amount. It should be noted that the beam waist of the condensed light beam was set so as to be located at the inner central portion (position of 0.25 mm from the substrate surface) of the photosensitive glass. After exposure with a predetermined integrated light amount shown below, the entire photosensitive glass substrate was heat treated at 580 ° C. for 4 hours.
In this case, the rate of temperature increase is 1 ° C./min, and the rate of temperature decrease is 0.2 ° C./min. After the heat treatment, a dilute hydrofluoric acid aqueous solution (about 7%) was used as an etching solution, and the etching solution was sprayed on the front and back of the photosensitive glass substrate to form through holes.

  At this time, the temperature of the etching solution was not particularly controlled. Table 1 shows the relationship between the integrated exposure amount and the through-hole diameter and aspect ratio in the vicinity of the central portion of the photosensitive glass substrate. In addition, the shape of the through hole formed in the present embodiment is the same as the shape shown in FIG. 2b, the hole diameter in the vicinity of the front and back surfaces of the substrate is larger than that in the vicinity of the center of the substrate, and the uniform through hole diameter. The part from which it was obtained was from the part which entered about 75 μm inside from the front and back surfaces of the substrate. This is because, as described above, even in a region where a latent image is not formed, planar etching on the surface of the photosensitive glass also proceeds with the progress of etching of the latent image forming region.

Therefore, the aspect ratio shown in Table 1 is calculated with the substrate thickness set to 0.35 mm. As shown in the table, the diameter of the through hole is increased with the increase of the integrated exposure amount. This is because the area where the latent image is formed is enlarged as the integrated exposure amount is increased.

This example is an example according to the second embodiment described above. The through hole formation conditions in this example are the same as those described in Example 1 except for the exposure process. In this example, exposure of the photosensitive glass substrate was performed by dividing it into first and second exposure processes. In the first exposure process, as shown in the figure, exposure is performed by setting the position of the beam waist of the condensed light beam to a position of 1/4 of the substrate thickness from the surface of the photosensitive glass substrate, and the second exposure process. In the exposure process, as shown in FIG. 4b, the same position was set to a position 3/4 of the substrate thickness from the surface of the photosensitive glass substrate. The exposure conditions such as the first and second integrated exposure amounts are the same. Table 2 shows the relationship between the integrated exposure amount and the through-hole diameter and aspect ratio at the central portion of the photosensitive glass substrate. The method for obtaining the aspect ratio is the same as in the first embodiment.

  The present invention relates to a glass component having a through hole having a uniform and fine diameter and a method for producing the same, and can be used as a printed wiring board, an inkjet print head, a gas flow meter component, or the like.

It is explanatory drawing of the manufacturing method of the glass component which has a through-hole concerning the 1st Embodiment of this invention. Description of a latent image formed when the exposure amount E by the condensed light beam 21 in FIG. 1 is set to an exposure critical value necessary for forming a latent image of the photosensitive glass 100 and a through hole formed based on the latent image FIG. It is explanatory drawing of the manufacturing method of the glass component which has a through-hole concerning the 2nd Embodiment of this invention. It is explanatory drawing of a two-step exposure process. It is explanatory drawing of a two-step exposure process. It is explanatory drawing of the latent image formation process by the ultraviolet exposure using the conventional photomask. It is a figure which shows typically the hole formed when a latent image formation area | region is etched and removed through heat processing after forming a latent image. It is explanatory drawing of the manufacturing method of the glass component which has a through-hole disclosed in patent document 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Photosensitive glass 21 Condensed light beam 21a Beam waist 22 Light quantity distribution 23 along AA 'line Light quantity distribution along BB' line

Claims (1)

A first step of forming a latent image by irradiating a portion of the photosensitive glass substrate forming a through hole with a condensed light beam;
A second step of crystallizing the portion where the latent image is formed by heat-treating the photosensitive glass irradiated with the condensed light beam in the first step;
And a third step of forming a through hole by dissolving and removing the portion crystallized in the second step, and a method for producing a glass component having a through hole,
In the first step, the condensed light beam is irradiated so that a beam waist of the condensed light beam is located at an inner central portion of the photosensitive glass,
In the condensed light flux, the exposure distribution is centered on the beam waist position so that a cylindrical latent image region having a uniform radius in the thickness direction of the photosensitive glass substrate is formed. A position that has a point-symmetrical relationship and has a light quantity that is an exposure critical value necessary for forming a latent image is a certain distance from the optical axis of the condensed light flux in a direction along the front and back surfaces of the substrate-like photosensitive glass. The manufacturing method of the glass component which has a through-hole characterized by the above-mentioned relationship.

Images