JP6936954B2 - Glass substrate for microchannel devices - Google Patents

Description

The present invention relates to a glass substrate for a microchannel device.

A microchannel device is a device capable of performing various chemical operations such as reaction, separation, purification, and detection by handling a very small amount of sample. Since biotechnology and chemical analysis are microscaled, various applications are expected in the medical and biotechnology fields, such as reduction of environmental load, time, and cost, high reaction efficiency, and space saving. The microchannel device is manufactured by joining a substrate on which a channel is formed and a substrate that covers the substrate. The use of quartz glass as a substrate for microchannel devices is being studied. (See, for example, Patent Document 1)

Japanese Unexamined Patent Publication No. 2006-300563

However, since quartz glass has a high softening point, it is necessary to join the quartz glass to each other at a high temperature, which causes a problem that the production time is long and the cost is high.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a glass substrate for a microchannel device, which can shorten the manufacturing time of the microchannel device and reduce the cost.

The glass substrate for a microchannel device of the present invention has a glass composition of SiO ₂ 50 to 85%, Al ₂ O _{30 to} 20%, B ₂ O _{30 to} 17%, MgO 0 to 10% in mass%. , CaO 0 to 15%, SrO 0 to 15%, BaO 0 to 10%, R ₂ O (R is at least one selected from Li, Na and K) 0.1 to 10%. And.

A glass substrate for the microchannel device of the present invention is a multi-component, addition, since the contain a R 2 _O as an essential component, it is possible to lower the softening point. Since the softening point is low, the glass substrates can be joined at a low temperature. Therefore, the microchannel device can be manufactured in a short time, easily, and at low cost.

The glass substrate for a microchannel device of the present invention preferably has a softening point of 900 ° C. or lower. In this way, the glass substrates can be joined at a low temperature, which tends to lead to cost reduction.

The glass substrate for a microchannel device of the present invention preferably has a coefficient of thermal expansion (30 to 380 ° C.) of 80 × ^10-7 / ° C. or less. In this way, the glass is less likely to be damaged when the glass is rapidly cooled after the heat treatment for joining the glass substrates is performed.

The glass substrate for a microchannel device of the present invention preferably has a strain point of 500 ° C. or higher.

A glass substrate for the microchannel device of the present invention, it is preferable liquidus viscosity of 10 ^{4.0 dPa} · s or more.

The glass substrate for a microchannel device of the present invention preferably has a surface roughness Ra of 100 Å or less. In this way, the substrates can be easily joined to each other.

By using the glass substrate of the present invention, the manufacturing time of the microchannel device can be shortened, so that the microchannel device can be provided at low cost.

The reasons for limiting the glass composition as described above in the glass substrate for the microchannel device of the present invention are shown below. In the following description of each component, "%" means "mass%" unless otherwise specified.

SiO ₂ is a component that expands the vitrification range to facilitate vitrification and improves chemical durability. The content of SiO ₂ is 50 to 85%, preferably 55 to 82%, 60 to 79%, 65 to 76%, and particularly preferably 68 to 73%. If _{the content of SiO 2} is too small, it becomes difficult to form a glass network structure, vitrification tends to be difficult, the crack occurrence rate tends to increase, and the chemical durability tends to decrease. On the other hand, if _{the content of SiO 2} is too large, the meltability and moldability tend to decrease.

Al ₂ O ₃ is a component that improves chemical durability and enhances Young's modulus and strain point. The content of Al ₂ O ₃ is 0 to 20%, preferably 1 to 15%, 2 to 12%, 3 to 10%, and particularly preferably 5 to 8%. If _{the content of Al 2} O ₃ is too large, devitrified crystals are precipitated in the glass, and the liquidus viscosity tends to decrease.

B ₂ O ₃ is a component that lowers the softening point, liquid phase temperature, and density. The content of B ₂ O ₃ is 0 to 17%, 2 to 15%, 3 to 13%, 5 to 13%, 8 to 13%, 10 to 13%, 10.5 to 13%, especially 12 ~ 13% is preferable. If _{the content of B 2} O ₃ is too large, the strain point, Young's modulus, and acid resistance tend to decrease.

R ₂ O (R is at least one selected from Li, Na and K) is a component that lowers the softening point and the liquidus temperature. The content of R ₂ O (total amount of Li ₂ O, Na ₂ O and K ₂ O) is 0.1 to 10%, 0.5 to 10%, 1 to 8%, 2 to 7%, 3 to 7%, particularly 4 to 7% is preferable. When the content of R 2 _O is too small, the effect is difficult to obtain. On the other hand, when the content of R 2 _O is too large, the high temperature viscosity becomes higher, bubbles or the like are likely to occur in the glass.

The content of each component of R 2 _O is preferably as follows.

The content of Li ₂ O is preferably 0 to 10%, 0 to 5%, 0 to 3%, 0 to 1%, and particularly preferably 0 to 0.2%. If _{the content of Li 2} O is too large, the alkali elution becomes too large, the density and the coefficient of thermal expansion become high, and the devitrification tendency becomes strong.

Na ₂ O is a component that lowers the softening point and liquid phase temperature. The Na2O content is preferably 0.1 to 10%, 0.5 to 8%, 1 to 7%, 2 to 7%, 3 to 7%, and particularly preferably 4 to 7%. If _{the content of Na 2} O is too small, it becomes difficult to obtain the above effect. On the other hand, _{if the content of Na 2} O is too large, the alkali elution becomes too large, and the density and the coefficient of thermal expansion become high.

The content of K ₂ O is preferably 0 to 10%, 0 to 5%, 0 to 3%, 0 to 1%, and particularly preferably 0 to 0.2%. If the K ₂ O content is too high, the alkali elution will be too high, and the density and coefficient of thermal expansion will be high.

MgO is a component that increases Young's modulus and strain point, and lowers high-temperature viscosity and crack generation rate. The content of MgO is 0 to 10%, preferably 0 to 5%, 0 to 3%, 0 to 2%, 0 to 1.5%, 0 to 1%, and particularly 0 to 0.5%. If the content of MgO is too large, the liquidus temperature rises and the devitrification resistance tends to decrease.

CaO is a component that increases Young's modulus and strain point, and lowers high-temperature viscosity and crack generation rate. The CaO content is 0 to 15%, preferably 0.5 to 12%, 1 to 10%, 1 to 9%, and particularly preferably 1 to 8.5%. If the CaO content is too high, the density and coefficient of thermal expansion tend to increase.

SrO is a component that increases Young's modulus and strain point, and lowers high-temperature viscosity and crack generation rate. The content of SrO is 0 to 15%, preferably 0 to 12%, 0 to 8%, 0 to 5%, 0 to 3%, and particularly preferably 0 to 1%. If the content of SrO is too large, the density and coefficient of thermal expansion tend to increase.

BaO is a component that improves chemical durability. The content of BaO is preferably 0 to 10%, 0.1 to 7%, 0.5 to 5%, 0.5 to 3%, and particularly preferably 0.5 to 2%. If the BaO content is too high, the density and coefficient of thermal expansion tend to increase.

When a plurality of each component of MgO, CaO, SrO, and BaO is introduced, the liquidus temperature is lowered and crystalline foreign substances are less likely to be generated in the glass. The total amount of these components is preferably 0.1 to 30%, 0.5 to 15%, 1 to 8%, and particularly preferably 1 to 5%. If the total amount of these components is too small, it becomes difficult to obtain the above effect. On the other hand, if the total amount of these components is too large, the density increases, it becomes difficult to reduce the weight of the glass, and the crack occurrence rate tends to increase.

The glass constituting the present invention may contain the following components in addition to the above components.

The content of Fe ₂ O ₃ is preferably 300 ppm or less, 200 ppm or less, 150 ppm or less, 100 ppm or less, 80 ppm or less, 50 ppm or less, and particularly preferably 30 ppm or less. The _{smaller the content of Fe 2} O _3, the higher the transmittance, which makes it easier to observe the liquid in the microchannel. In _{order to reduce the content of Fe 2} O ₃ , it is preferable to use a high-purity raw material. The lower limit of the content of Fe ₂ O ₃ is not particularly limited, but in reality, it is 5 ppm or more, and further 10 ppm or more.

Y ₂ O ₃ , Nb ₂ O ₃ , and La ₂ O ₃ are components that increase the strain point, Young's modulus, and the like. However, if the content of these components is too large, the density tends to be high. Therefore, _{the content of Y 2} O ₃ , Nb ₂ O ₃ , and La ₂ O ₃ is preferably 3% or less, respectively.

As the clarifying agent, 0 to 3% of one or more selected from the group of _{As 2} O ₃ , Sb ₂ O ₃ , CeO ₂ , SnO ₂ , F, Cl and SO _{3 may be added.} However, _{it is preferable to refrain from using As 2} O ₃ , Sb ₂ O ₃ and F, especially As ₂ O ₃ and Sb ₂ O _3, from an environmental point of view, and the content of each is less than 0.1%. It is preferable to limit to. Preferred clarifiers are SnO ₂ , SO ₃ and Cl. The SnO ₂ content is preferably 0 to 1%, 0.01 to 0.5%, and particularly 0.05 to 0.4%. The content of SnO ₂ + SO ₃ + Cl (the _{total amount of SnO 2} , SO ₃ and Cl) is preferably 0.001 to 1%, 0.01 to 0.5%, and particularly 0.01 to 0.3. %.

The glass substrate for a microchannel device of the present invention preferably has a softening point of 900 ° C. or lower, 880 ° C. or lower, 860 ° C. or lower, 840 ° C. or lower, and particularly preferably 820 ° C. or lower. If the softening point is too high, the temperature at which the glass substrates are joined rises, making it difficult to manufacture a microchannel device at low cost.

The glass substrate for a microchannel device of the present invention has a coefficient of thermal expansion (30 to 380 ° C.) of 80 × ^10-7 / ° C. or less, 75 × ^10-7 / ° C. or less, 70 × ^10-7 / ° C. or less, particularly. It is preferably 68 × 10 ^-7 / ° C. or lower. If the coefficient of thermal expansion is too high, the glass substrates are likely to be damaged when the glass substrates are rapidly cooled after the heat treatment for joining them.

When a plurality of glass substrates are bonded together, the difference in the coefficient of thermal expansion of each glass substrate to be bonded is 5 × 10 ^-7 / ° C or less, 3 × 10 ^-7 / ° C or less, and 2 × 10 ^-7 / ° C or less. It is preferably 1 × 10 ^-7 / ° C or less, particularly preferably 0.5 × 10 ^-7 / ° C or less. If the difference in the coefficient of thermal expansion is too large, the glass substrate is likely to be damaged during joining and cooling, and the glass substrate is likely to be warped.

The glass substrate for a microchannel device of the present invention preferably has a strain point of 500 ° C. or higher, particularly 520 ° C. or higher. If the strain point is too low, the heat resistance tends to decrease, and even if the heat treatment for reuse is performed at a high temperature after conducting an experiment using various solvents, the glass substrate is unlikely to be deformed or deteriorated. It will be easier to use. By treating at a high temperature, the amount of organic matter remaining in the flow path can be reduced to almost zero.

The glass substrate for a microchannel device of the present invention has a liquid phase viscosity of 10 ^4.0 dPa · s or more, 10 ^5.0 dPa · s or more, 10 ^5.6 dPa · s or more, and 10 ^5.8 dPa ·. It is preferably s or more, particularly ^106.0 dPa · s or more. Further, the liquid phase temperature is preferably 1200 ° C. or lower, 1150 ° C. or lower, 1130 ° C. or lower, 1110 ° C. or lower, 1090 ° C. or lower, particularly 1070 ° C. or lower. If the liquidus viscosity is too low and the liquidus temperature is too high, the glass tends to devitrify during molding.

The glass substrate for a microchannel device of the present invention preferably has a crack generation rate of 70% or less, 50% or less, 40% or less, 30% or less, and particularly preferably 20% or less. If the crack occurrence rate is too high, the glass substrate is liable to be damaged. Here, the "crack generation rate" is determined by driving a Vickers indenter set to a load of 1000 g into a glass surface (optically polished surface) for 15 seconds in a constant temperature and humidity chamber maintained at a humidity of 30% and a temperature of 25 ° C. After 15 seconds, the number of cracks generated from the four corners of the indentation is counted (maximum of 4 per indentation), this operation is repeated 20 times (that is, the indenter is driven 20 times), and the total number of cracks is counted. , (Total number of cracks generated / 80) × 100 (%).

The glass substrate for a microchannel device of the present invention preferably has a Young's modulus of 65 GPa or more, 67 GPa or more, 68 GPa or more, 69 GPa or more, 70 GPa or more, 71 GPa or more, 72 GPa or more, and particularly 75 GPa or more. If the Young's modulus is too low, the glass substrate tends to warp, and problems such as breakage tend to occur.

The glass substrate for a microchannel device of the present invention has a density of 2.7 g / cm ³ or less, 2.6 g / cm ³ or less, 2.5 g / cm ³ or less, and particularly 2.4 g / cm ³ or less. preferable. If the density is too high, it will be difficult to reduce the weight of the microchannel device.

The glass substrate for a microchannel device of the present invention has a transmittance of 30% or more, 50% or more, 70% or more, 80% or more, 85% or more, particularly 89% or more at a wavelength of 300 nm at a thickness of 500 μm. preferable. Further, the transmittance at a wavelength of 350 nm is preferably 50% or more, 70% or more, 80% or more, 85% or more, 89% or more, 90% or more, particularly 91% or more. Further, the transmittance at a wavelength of 550 nm is preferably 85% or more, 89% or more, 90% or more, particularly 91% or more. If the transmittance is too low, it is difficult to obtain a clear image when observing the liquid flowing in the flow path.

Next, a method for manufacturing the glass substrate for the microchannel device of the present invention will be described.

First, a glass raw material prepared so as to have a desired composition is heated and melted to obtain a glass melt. Next, the obtained glass melt is plate-molded to obtain a glass substrate for a microdevice. The method of plate drawing is not limited, but it is preferably formed by the overflow down draw method. The glass substrate produced by this method has excellent surface quality and does not require polishing. The reason why the glass substrate formed by the overflow down draw method is excellent in surface quality is that the surface to be the surface of the glass substrate does not come into contact with the gutter-shaped refractory and is formed in a free surface state. Here, in the overflow down draw method, the molten glass is overflowed from both sides of the heat-resistant gutter-shaped structure, and the overflowed molten glass is stretched downward while being merged at the lower end of the gutter-shaped structure to form a glass substrate. Is a method of manufacturing. The structure and material of the gutter-shaped structure are not particularly limited as long as the dimensions and surface accuracy of the glass substrate are in a desired state and the quality that can be used for the glass substrate can be realized. In addition, a force may be applied to the glass in any way in order to perform downward stretching molding. For example, a method of rotating and stretching a heat-resistant roll having a sufficiently large width in contact with the glass may be adopted, or a plurality of pairs of heat-resistant rolls may be brought into contact with only the vicinity of the end face of the glass. You may adopt the method of letting and stretching. In addition to the overflow down draw method, for example, a molding method such as a slot down method or a redraw method can also be adopted.

The obtained glass substrate preferably has an unpolished surface. The theoretical strength of glass is originally very high, but stress far lower than the theoretical strength often leads to fracture. This is because a small defect called Griffith flow occurs on the surface of the glass substrate in a process after molding the glass, for example, a polishing process. Therefore, if the surface of the glass substrate is unpolished, the original mechanical strength is less likely to be impaired, and the glass substrate is less likely to be broken. Moreover, since the polishing step can be omitted, the manufacturing cost of the glass substrate can be reduced. If the entire effective surface of both surfaces is an unpolished surface, the glass substrate is more difficult to break.

The surface roughness Ra of the obtained glass substrate is preferably 100 Å or less, 50 Å or less, 10 Å or less, 8 Å or less, 4 Å or less, 3 Å or less, and particularly preferably 2 Å or less. If the surface roughness Ra of the surface of the glass substrate is too large, it becomes difficult to bond the substrates to each other. The surface roughness Ra of the end face of the glass substrate is preferably 100 Å or less, 50 Å or less, 10 Å or less, 8 Å or less, 4 Å or less, 3 Å or less, and particularly preferably 2 Å or less. If the surface roughness Ra of the end face of the glass substrate is too large, the glass substrate is liable to be damaged. The waviness of the glass substrate is preferably 1 μm or less, 0.08 μm or less, 0.05 μm or less, 0.03 μm or less, 0.02 μm or less, and particularly preferably 0.01 μm or less. If the swell of the glass substrate is too large, it becomes difficult to join the substrates.
Further, the difference between the maximum thickness and the minimum thickness of the glass substrate is preferably 10 μm or less, 5 μm or less, 2 μm or less, and particularly preferably 1 μm or less. If this difference is too large, it becomes difficult to join the substrates.

The width dimension of the glass substrate for the microchannel is preferably 500 mm or more, 600 mm or more, 800 mm or more, 1000 mm or more, 1200 mm or more, 1500 mm or more, and particularly preferably 2000 mm or more. In this way, it is possible to manufacture a large number of microchannel devices at one time by writing a flow path on a large glass substrate by photolithography or a laser, laminating the cover glass, and then cutting the flow path.

Next, a method of manufacturing a microchannel device using the glass substrate for a microchannel device of the present invention will be described. The microchannel device is composed of a flow path forming substrate and a glass substrate covering the substrate (hereinafter referred to as a cover glass substrate), and the glass substrate of the present invention is a flow path forming substrate and a cover glass substrate. It can be used for both.

A glass substrate for forming a flow path and a glass substrate for a cover are produced by the above method. The thickness of the glass substrate for forming a flow path is 30 to 3000 μm, 50 to 2800 μm, 100 to 2000 μm, 200 to 1800 μm, 200 to 1500 μm, 200 to 1200 μm, 200 to 1000 μm, 200 to 800 μm, 200 to 700 μm, 200 to 500 μm, in particular. It is preferably 200 to 300 μm. If the thickness is too small, the rigidity of the entire device will be insufficient and it will be easily damaged during handling. On the other hand, if the thickness is too large, it becomes difficult to reduce the weight of the flow path device. The thickness of the glass substrate for the cover is preferably 1000 μm or less, 700 μm or less, 600 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, and particularly preferably 50 μm or less. The lower limit of the thickness is not particularly limited, but in reality, it is 5 μm or more. If the thickness is too large, it becomes difficult to attach the cover glass substrate onto the flow path forming glass substrate while bending it, and it becomes easy for air to be entrained between the laminated glasses.

Next, a flow path is formed on the flow path forming glass substrate. Photolithography, laser, or the like can be used to form the flow path. A flow path forming glass substrate and a cover glass substrate on which a flow path is formed are heat-sealed at 500 to 900 ° C. to obtain a micro flow path device. If the heat fusion temperature is too high here, the flow path pattern tends to melt. On the other hand, if it is too low, it becomes difficult for the substrates to fuse with each other.

A flow path formed of through holes may be formed on the flow path forming glass substrate. In this case, the glass substrate for the cover is joined to both sides of the glass substrate for forming the flow path. In this case, the thickness of the flow path forming glass substrate is preferably 500 μm or less, 300 μm or less, 100 μm or less, 70 μm or less, 50 μm or less, and particularly preferably 30 μm or less. If the thickness is too large, the tact time increases when the through hole is produced by photolithography, laser, or the like, so that the manufacturing cost tends to increase. The thickness of the glass substrate for the cover is preferably 2000 μm or less, 1800 μm or less, 1500 μm or less, 1200 μm or less, 1000 μm or less, 800 μm or less, 700 μm or less, 500 μm or less, and particularly preferably 300 μm or less. The lower limit of the thickness is not particularly limited, but in reality, it is 5 μm or more. If the thickness is too large, it becomes difficult to reduce the weight of the flow path device.

A suitable example of the glass substrate used in the present invention will be described below. However, the following examples are merely examples. The glass substrate used in the present invention is not limited to the following examples.

Table 1 shows the glass composition and characteristics of the glass substrate (Samples Nos. 1 to 3).

First, glass raw materials were prepared so as to have the glass composition shown in Table 1, and the obtained glass raw materials were supplied to a glass melting furnace and melted at 1500 to 1600 ° C. Next, the obtained molten glass was formed by an overflow down draw method so as to have a thickness and a width dimension of 1500 mm in the table. Subsequently, the glass substrate immediately after molding was moved to a slow cooling area and cooled to obtain a flow path forming glass substrate and a cover glass substrate. At that time, the temperature of the slow cooling area and the substrate withdrawal speed were adjusted so that the cooling rate at the temperature of ^{10 12} to ^{14 dPa · s was 20 ° C./min.} A flow path was formed on the obtained glass substrate for forming a flow path by a laser. Then, the glass substrate for forming the flow path and the glass substrate for the cover were heat-sealed at 500 to 900 ° C. to prepare a micro flow path device.

As is clear from Table 1, the sample No. In Nos. 1 to 3, the softening point was as low as 740 to 792 ° C., so that the heat fusion temperature was low. In addition, sample No. Nos. 1 to 3 had a small thickness and good surface accuracy. Therefore, it was possible to manufacture the microchannel device without causing an increase in cost.

The density is a value measured by the well-known Archimedes method.

The strain point is a value measured based on the method of ASTM C336-71.

The glass transition temperature is a value measured from the thermal expansion curve based on the method of JIS R3103-3.

The softening point is a value measured based on the method of ASTM C338-93.

The temperature at 10 ^4.0 , 10 ^3.0 , and 10 ^2.5 dPa · s is a value measured by the platinum ball pulling method. The lower this temperature, the better the meltability.

Young's modulus is a value measured by the resonance method.

The coefficient of thermal expansion is a measurement of the average coefficient of thermal expansion at 30 to 380 ° C. using a dilatometer. As a sample for measuring the coefficient of thermal expansion, a cylindrical sample having a diameter of 5 mm × 20 mm with an R-processed end face was used.

The liquidus temperature was measured by passing through a standard sieve of 30 mesh (500 μm), placing the glass powder remaining in 50 mesh (300 μm) in a platinum boat, and holding it in a temperature gradient furnace for 24 hours to measure the temperature at which crystals precipitate. It is a thing. The liquidus viscosity is a value obtained by measuring the viscosity of glass at the liquidus temperature by the platinum ball pulling method.

The chemical durability was confirmed by the following method. The water resistance was confirmed in accordance with ISO719 and JISR3502, the alkali resistance was confirmed in accordance with ISO695, and the acid resistance was confirmed in accordance with DIN12116.

The surface roughness Ra of the surface is a value measured by a method according to JIS B0601: 2001.

The surface roughness Ra of the end face is a value measured by a method according to JIS B0601: 2001.

The swell is a value obtained by measuring WCA (perpendicular center line swell) described in JIS B0601: 2001 using a stylus type surface shape measuring device, and this measurement is SEMI STD D15-1296 "FPD glass plate". The cutoff at the time of measurement is 0.8 to 8 mm, and the length is 300 mm in the direction perpendicular to the pull-out direction of the glass substrate.

The difference between the maximum thickness and the minimum thickness of the glass substrate is determined by measuring the maximum thickness and the minimum thickness of the glass substrate by scanning the laser from the thickness direction on any one side of the glass substrate using a laser type thickness measuring device. Is the value obtained by subtracting the minimum thickness value from the maximum thickness value.

The transmittance was measured using a UV-3100PC under the conditions of slit width: 2.0 nm, scanning speed: medium speed, and sampling pitch: 0.5 nm.

Claims (7)

As the glass composition, in _{terms of mass%, SiO 2} 65-85%, Al ₂ O ₃ 6.9 to 20%, B ₂ O _{30 to} 17%, MgO 0 to 10%, CaO 0 to 15%, SrO 0 to 0 _{15%, BaO 0.1 ~1.2%,} ( at least one R is Li, is selected from Na and _{K) R 2 O 7.9 ~10%} , Li 2 O 0~1%, Na 2 O A glass substrate for a microchannel device containing 5.9 to 10% and having a surface waviness of 0.08 μm or less. The glass substrate for a microchannel device according to claim 1, wherein the softening point is 900 ° C. or lower. The glass substrate for a microchannel device according to claim 1 or 2, wherein the coefficient of thermal expansion (30 to 380 ° C.) is 80 × ^{10-7 / ° C. or less.} The glass substrate for a microchannel device according to any one of claims 1 to 3, wherein the strain point is 500 ° C. or higher. Microchannel glass substrate device according to claim 1, wherein the liquidus viscosity of 10 ^{4.0 dPa} · s or more. The glass substrate for a microchannel device according to any one of claims 1 to 5, wherein the surface roughness Ra is 100 Å or less. The glass substrate for a microchannel device according to any one of claims 1 to 6, wherein the difference between the maximum thickness and the minimum thickness of the glass substrate is 5 μm or less.