JP5418971B2 - Glass film - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a glass film, specifically, a display substrate such as a liquid crystal display or an organic EL display, a chip size package (CSP), a charge coupled device (CCD), an equal magnification proximity solid-state imaging device (CIS), or the like. The present invention relates to a glass film suitable for an image sensor substrate, a substrate for an illumination device such as organic EL lighting, and a wiring substrate.

  In recent years, devices such as organic EL displays have been reduced in size, thickness, and weight. Moreover, these devices are mounted on mobile phones, notebook PCs, TVs, and the like, and it is desired to further reduce power consumption in the future. Moreover, these devices are not only used in a flat state but also used in a curved shape. For example, a case used for a display part of a flexible wristwatch or a display part installed on a curved wall. Is also increasing.

JP 2008-305557 A JP 2009-70759 A

  In general, a glass substrate having a thickness of 0.5 to 0.7 mm is used for an organic EL display or the like. However, the glass substrate having a thickness of 0.5 to 0.7 mm has a problem that it cannot be applied to a use in which the glass substrate is bent into a curved surface because of poor flexibility.

  In addition, an organic EL display or the like has a mechanism in which display of a pixel is changed by a current flowing through the EL element being changed by an electric signal sent to each pixel. However, when a voltage is applied to each pixel, an opposite charge is induced on the substrate, and this induced charge lowers the voltage to be applied to the pixel electrode, resulting in an increase in the driving voltage of the TFT. There is a possibility that power consumption becomes high. Furthermore, when a voltage is applied to each pixel, the substrate may generate heat and adversely affect the operation characteristics of the device.

  Therefore, the present invention can be curved into a curved surface by creating a substrate material that has flexibility and is less likely to induce charge on the substrate and to generate heat when a voltage is applied to each pixel. Therefore, it is a technical problem to manufacture a device with low power consumption and high reliability.

  As a result of repeating various experiments, the present inventors have found that the above technical problem can be solved by using a glass film having a small film thickness as a substrate material and reducing the dielectric constant and dielectric loss tangent of the glass film. This is proposed as the present invention. That is, the glass film of the present invention has a film thickness of 100 μm or less, a dielectric constant at a frequency of 1 MHz, and a dielectric loss tangent at a frequency of 1 MHz of 0.5 or less. Here, “dielectric constant at a frequency of 1 MHz” refers to a value measured at 25 ° C. by a method based on ASTM D150. The “dielectric loss tangent at a frequency of 1 MHz” refers to a value measured by a method based on ASTM D150 at 25 ° C.

  If the film thickness of the glass film is regulated to 100 μm or less, flexibility can be enhanced. When this glass film is used for a substrate, it becomes easy to produce a flexible device. Moreover, if the dielectric constant of the glass film is regulated to 5 or less, the amount of charge induced when a voltage is applied to the pixel electrode can be suppressed, and as a result, the power consumption of the device increases. Can be prevented. Furthermore, if the dielectric loss tangent of the glass film is regulated to 0.5 or less, it is possible to prevent the glass film from generating heat and adversely affecting the operation characteristics of the device.

Second, the glass film of the present invention has a glass composition, in _{mass%, SiO 2 40~80%, Al} 2 O 3 0~20%, B 2 O 3 10~30%, 0~10% MgO, CaO 0 to 10%, SrO 0 to 10%, BaO 0 to 10% are contained.

Thirdly, the glass film of the present invention has a glass composition, in _{mass%, SiO 2 55~75%, Al} 2 O 3 10~20%, B 2 O 3 13~30%, 0~4% MgO, _{CaO 1~10%, SrO 0~5%,} BaO 0~5%, Li 2 O + Na 2 O + K 2 O (Li 2 O, Na 2 O, the total content of _{K 2} O), characterized in that it contains 6% And

Fourth, the glass film of the present invention has a glass composition, in _{mass%, SiO 2 55~63%, Al} 2 O 3 10~20%, B 2 O 3 13~20%, 0~2% MgO, CaO 6-10%, SrO 0-3%, BaO 0-3%, MgO + CaO + SrO + BaO (total amount of MgO, CaO, SrO, BaO) 6.5-10%, Li ₂ O + Na ₂ O + K ₂ O 0-0.1 % Content.

Fifth, the glass film of the present invention has a thermal expansion coefficient of 25 to 50 × 10 ⁻⁷ / ° C. Here, the “thermal expansion coefficient” refers to an average value measured with a dilatometer in a temperature range of 30 to 380 ° C. In general, in an organic EL display or the like, a low expansion Si-based film (thermal expansion coefficient: about 32 to 34 × 10 ⁻⁷ / ° C.) is formed on a substrate. For this reason, if the thermal expansion coefficients of the glass film and Si are mismatched, the glass film is warped. Therefore, if the thermal expansion coefficient of the glass film is regulated within the above range, it becomes easy to match the thermal expansion coefficient of Si, and as a result, it becomes easy to prevent warping of the glass film.

Sixth, the glass film of the present invention has a liquidus viscosity of 10 ^4.0 dPa · s or more. Here, “liquid phase viscosity” refers to a value obtained by measuring the viscosity of glass at the liquid phase temperature by a platinum ball pulling method. In addition, the “liquid phase temperature” passes through a standard sieve 30 mesh (500 μm), and the glass powder remaining in 50 mesh (300 μm) is placed in a platinum boat and kept in a temperature gradient furnace for 24 hours to precipitate crystals. Refers to the value measured temperature. In addition, the higher the liquidus viscosity and the lower the liquidus temperature, the better the devitrification resistance and the moldability.

  Seventh, the glass film of the present invention is formed by an overflow down draw method. Here, the “overflow down draw method” is also referred to as a fusion method. The molten glass is overflowed from both sides of the heat-resistant cage structure, and the overflowed molten glass is joined at the lower end of the cage structure. However, this is a method for producing a glass film by stretching downward.

  Eighth, the glass film of the present invention is used for a substrate of an organic EL display.

  Ninthly, the glass film of the present invention is used for a wiring board.

  In the glass film of the present invention, the film thickness is 100 μm or less, preferably 80 μm or less, 50 μm or less, and particularly preferably 30 μm or less. The smaller the film thickness, the lighter the glass film and, as a result, the lighter the device. Moreover, since the flexibility of a glass film improves so that film thickness is small, it becomes easy to provide flexibility to a device and it becomes easy to install a device in the curved part.

  In the glass film of the present invention, the dielectric constant at 1 MHz is 5 or less, preferably 4.9 or less, more preferably 4.8 or less. When the dielectric constant increases, the charge induced when a voltage is applied to the pixel electrode increases, and the power consumption tends to increase.

  In the glass film of the present invention, the dielectric loss tangent at 1 MHz is 0.5 or less, preferably 0.1 or less, more preferably 0.01 or less, still more preferably 0.005 or less, particularly preferably 0.001 or less, Most preferably, it is 0.0005 or less. When the dielectric loss tangent increases, the glass film generates heat, which may adversely affect the operation characteristics of the device.

  The reason for limiting the content of each component in the glass composition as described above in the glass film of the present invention will be described below.

The content of SiO ₂ is 40 to 80%, preferably 50 to 75%, more preferably 55 to 70%, still more preferably 57 to 63%, and most preferably 58 to 62%. When the content of SiO ₂ is less than 40%, it is difficult to reduce the density. On the other hand, when the content of SiO ₂ is more than 80%, the high temperature viscosity becomes high and the meltability is lowered. In addition, defects such as devitrified crystals (cristobalite) are likely to occur in the glass.

The content of Al ₂ O ₃ is 0 to 20%. When the content of Al ₂ O ₃ is less or hardly enhance the heat resistance, the higher the viscosity at high temperature, the melting property tends to decrease. Therefore, the preferred lower limit range of Al ₂ O ₃ is 0.1% or more, 3% or more, 5% or more, 10% or more, 12% or more, 14% or more, 14.5% or more, 15% or more, particularly 15 .5% or more. On the other hand, when the content of Al ₂ O ₃ is large, the liquidus temperature increases, devitrification resistance tends to decrease. Therefore, the preferable upper limit range of Al ₂ O ₃ is 19% or less, 18% or less, and particularly 17% or less.

B ₂ O ₃ is a component that lowers the dielectric constant. Moreover, it is a component which acts as a flux, lowers the high temperature viscosity, and improves the meltability, and its content is 10 to 30%. When the content of B ₂ O ₃ is small, it becomes difficult to lower the dielectric constant, and the function as a flux becomes insufficient, so that the high-temperature viscosity becomes high and the bubble quality tends to be lowered. Furthermore, it is difficult to reduce the density of the glass. Therefore, the preferable lower limit range of B ₂ O ₃ is 11% or more, 11.5% or more, 12% or more, 13% or more, 14% or more, 15% or more, particularly 15.5% or more. On the other hand, if the content of B ₂ O ₃ is large, heat resistance and weather resistance tends to lower. Therefore, the preferable upper limit range of B ₂ O ₃ is 25% or less, 20% or less, 19% or less, 18% or less, particularly 17% or less.

  MgO is a component that increases the meltability by lowering the high-temperature viscosity without lowering the strain point, and is the component that has the effect of reducing the density most among the alkaline earth metal oxides. 0-10%, 0-6%, 0-2%, 0-1%, 0-0.5%, 0-0.1% are preferable. However, when the content of MgO is too large, the dielectric constant and dielectric loss tangent tend to be high. Moreover, when there is too much content of MgO, liquidus temperature will rise, devitrification resistance will fall easily, and also it will become easy to phase-divide glass, and there exists a possibility that transparency may be impaired.

  The content of CaO is 0 to 10%. CaO is a component that lowers the high-temperature viscosity without significantly lowering the strain point and significantly increases the meltability, and is a component that has a large effect of suppressing devitrification in the glass composition system according to the present invention. Furthermore, when the content is relatively increased in the alkaline earth metal oxide, the glass is easily reduced in density. Therefore, the preferable lower limit range of CaO is 1% or more, 2% or more, 3% or more, 6% or more, 6.5% or more, particularly 7% or more. On the other hand, if the content of CaO is large, the dielectric constant and dielectric loss tangent are likely to be high, the thermal expansion coefficient and density are too high, the component balance of the glass composition is impaired, and devitrification resistance is likely to be reduced. Become. Therefore, the preferable upper limit range of CaO is 9.5% or less, 9% or less, and particularly 8.5% or less.

  The content of SrO is 0 to 10%. SrO is a component that increases the meltability by lowering the high-temperature viscosity without lowering the strain point. However, as the SrO content increases, the density and thermal expansion coefficient tend to increase, and the dielectric constant and dielectric loss tangent. Will also rise. In addition, when the SrO content is increased, the CaO and MgO contents must be relatively reduced in order to match the thermal expansion coefficient of Si. It becomes easy to invite the situation where permeability falls and high temperature viscosity rises. Therefore, the content of SrO is preferably 0 to 5%, 0 to 2%, 0 to 1.5%, 0 to 1%, 0 to 0.5%, particularly preferably 0 to 0.1%.

  The content of BaO is 0 to 10%. BaO is a component that increases the meltability by lowering the high-temperature viscosity without lowering the strain point. However, as the content of BaO increases, the density and thermal expansion coefficient tend to increase, and the dielectric constant and dielectric loss tangent. Will also rise. Further, when the content of BaO increases, in order to match the thermal expansion coefficient of Si, the content of CaO and MgO must be relatively decreased, resulting in a decrease in devitrification resistance. , The high temperature viscosity is likely to increase. Therefore, the content of BaO is 0-6%, 0-3%, 0-2%, 0-1.5%, 0-1%, 0-0.5%, especially less than 0-0.1%. preferable.

  MgO + CaO + SrO + BaO is a component that lowers the liquidus temperature and makes it difficult to generate crystalline foreign matter in the glass, and is a component that improves meltability and formability, and its content is 0 to 25%, 1 to 20%, 3 to 15%, 5 to 10%, 6.5 to 9.5%, particularly 7 to 9% are preferable. When the content of MgO + CaO + SrO + BaO is small, the function as a flux cannot be sufficiently exhibited, and in addition to the decrease in meltability, the thermal expansion coefficient becomes too low and it becomes difficult to match the thermal expansion coefficient of Si. On the other hand, if the content of MgO + CaO + SrO + BaO is large, the density increases, it becomes difficult to reduce the weight of the glass, the specific Young's modulus decreases, and the thermal expansion coefficient becomes too high.

  In addition to the above components, other components can be added to the glass composition, for example, up to 25%, preferably up to 15%.

A fining agent is a component used to improve foam quality. Conventionally, As ₂ O ₃ and Sb ₂ O ₃ have been used as fining agents. However, As ₂ O ₃ and Sb ₂ O ₃ are environmentally hazardous substances, and it is required to reduce their usage from an environmental point of view. Therefore, when SnO ₂ is used as a fining agent, the foam quality can be improved while considering environmental requirements.

SnO ₂ is a component that exhibits a good clarification action in a high temperature range and a component that lowers the high temperature viscosity, and its content is 0 to 1%, 0.001 to 1%, 0.01 to 0.00. 5%, particularly 0.05 to 0.3% is preferable. When the content of SnO ₂ is more than 1%, a devitrified crystal of SnO ₂ is likely to be precipitated in the glass. Incidentally, when the content of SnO ₂ is less than 0.001%, it becomes difficult to enjoy the effect of the above.

As ₂ O ₃ and Sb ₂ O ₃ also act effectively as fining agents, and the present invention does not completely exclude the inclusion of these components, but from an environmental point of view, the content of these components is It is preferable to regulate to less than 0.1%, particularly less than 0.05%. In addition, halogens such as F and Cl lower the melting temperature and promote the action of the clarifying agent. As a result, it is possible to extend the life of the glass manufacturing kiln while reducing the melting cost. it can. However, if the content of F or Cl is too large, the metal wiring pattern formed on the glass film may be corroded. Therefore, the contents of F and Cl are preferably 1% or less, 0.5% or less, less than 0.1%, 0.05% or less, particularly 0.01% or less, respectively.

As described above, SnO ₂ is suitable as a fining agent, but CeO ₂ , SO ₃ , C, and metal powder (eg, Al, Si, etc.) can be added up to 5% as long as the glass properties are not impaired.

  ZnO is a component that enhances meltability, but as its content increases, the dielectric constant and dielectric loss tangent increase, the glass tends to devitrify, the strain point decreases, and the density also increases easily. Become. Therefore, the content of ZnO is preferably 0 to 10%, 0 to 5%, 0 to 3%, 0 to 0.5%, particularly preferably 0 to 0.3%, and ideally not substantially contained. desirable. Here, “substantially does not contain ZnO” refers to a case where the content of ZnO in the glass composition is 0.1% or less.

ZrO ₂ is a component that enhances the weather resistance, but as its content increases, the dielectric constant and dielectric loss tangent increase. Therefore, the content of ZrO ₂ is preferably 0 to 5%, 0 to 3%, 0 to 0.5%, particularly preferably 0 to 0.2%, and ideally not substantially contained. Here, “substantially does not contain ZrO ₂ ” refers to a case where the content of ZrO _{2 in} the glass composition is 0.01% or less. Incidentally, For greater weather resistance, it is preferable that a content of ZrO ₂ in 0.01% or more.

TiO ₂ is a component that lowers the viscosity at high temperature and increases the meltability, and is a component that suppresses solarization, but when added in a large amount in the glass composition, the dielectric constant and dielectric loss tangent increase, and the glass is colored. , The transmittance tends to decrease. Therefore, the content of TiO ₂ is preferably 0 to 5%, 0 to 3%, 0 to 1%, particularly preferably 0 to 0.02%.

P ₂ O ₅ is a component that enhances devitrification resistance. However, when it is added in a large amount in the glass composition, in addition to the occurrence of phase separation and milk white in the glass, the water resistance is significantly reduced. Therefore, the content of P ₂ O ₅ is preferably 0 to 5%, 0 to 1%, particularly preferably 0 to 0.5%.

Y ₂ O ₃ , Nb ₂ O ₅ , and La ₂ O ₃ have a function of increasing the strain point. However, when the content thereof is large, the dielectric constant, dielectric loss tangent, and density are likely to increase. Therefore, the content of these components is preferably 0 to 3%, 0 to 1%, particularly preferably 0 to 0.1%, respectively.

When the content of Li ₂ O + Na ₂ O + K ₂ O increases, the thermal expansion coefficient increases, the strain point decreases, and the TFT characteristics deteriorate. Therefore, the content of Li ₂ O + Na ₂ O + K ₂ O is preferably 0 to less than 10%, 0 to 6%, 0 to less than 5%, 0 to 3%, 0 to 1%, particularly preferably 0 to 0.1%. Ideally, it is desirable not to contain substantially. Here, "substantially free of _{Li 2 O + Na 2 O +} K 2 O ", the content of _{Li 2 O + Na 2 O +} K 2 O in the glass composition refers to a case of less than 0.1%.

In the glass film of the present invention, if the glass composition range is defined as follows, the dielectric constant decreases, and it becomes easy to match the thermal expansion coefficient of Si, the high temperature viscosity decreases, and the liquid phase viscosity is high. Prone.
(1) as a glass composition, in _{mass%, SiO 2 50~70%, Al} 2 O 3 0.1~20%, B 2 O 3 11~25%, MgO + CaO + SrO + BaO 5~13%, 0~10% MgO, CaO 0-9%, SrO 0-7%, BaO 0-7%, As ₂ O ₃ content less than 0.5%, Sb ₂ O ₃ content less than 0.5%, F The content is less than 0.1%, the Cl content is less than 0.1%, the alkali metal oxide content is less than 10%,
(2) as a glass composition, in _{mass%, SiO 2 55~70%, Al} 2 O 3 11~18%, B 2 O 3 12~22%, MgO + CaO + SrO + BaO 7~11%, MgO 0~9%, CaO 0 0.1 to 9%, SrO 0 to 6%, BaO 0 to 6%, As ₂ O ₃ content less than 0.1%, Sb ₂ O ₃ content less than 0.1%, F The content is less than 0.1%, the Cl content is less than 0.1%, the alkali metal oxide content is less than 5%,
(3) as a glass composition, in _{mass%, SiO 2 55~70%, Al} 2 O 3 12~17%, B 2 O 3 12~19%, MgO + CaO + SrO + BaO 7~11%, 0~5% MgO, CaO 2 -9%, SrO 0-3%, BaO 0-3%, As ₂ O ₃ content less than 0.1%, Sb ₂ O ₃ content less than 0.1%, F content Is less than 0.1%, the Cl content is less than 0.1%, the alkali metal oxide content is less than 1%,
(4) as a glass composition, in _{mass%, SiO 2 55~65%, Al} 2 O 3 13~18%, B 2 O 3 13~19%, MgO + CaO + SrO + BaO 7~10%, 0~1% MgO, CaO 6 0.5-9%, SrO 0-1%, BaO 0-1%, As ₂ O ₃ content less than 0.05%, Sb ₂ O ₃ content less than 0.05%, The content is less than 0.1%, the Cl content is less than 0.1%, the alkali metal oxide content is less than 0.1%,
(5) As a glass composition, by mass%, SiO ₂ 57 to 63%, Al ₂ O ₃ 15 to 17%, B ₂ O ₃ 15 to 18%, MgO + CaO + SrO + BaO 7 to 9%, MgO 0 to 1%, CaO 7 -9%, SrO 0-0.5%, BaO 0-0.5%, SnO ₂ 0.01-0.6%, As ₂ O ₃ content less than 0.05%, Sb ₂ O ₃ content is less than 0.05%, F content is less than 0.1%, Cl content is less than 0.1%, and alkali metal oxide content is less than 0.1%.

In order to lower the dielectric constant, it is generally effective to increase the content of SiO ₂ in the glass composition. However, in the case of an alkali-free glass or a low alkali glass, increasing the SiO ₂ content may significantly decrease the meltability. However, if the glass composition range is regulated as in the above (3) to (5), it is possible to suppress a decrease in meltability while reducing the dielectric constant.

In the glass film of the present invention, the density is 2.6 g / cm ³ or less, 2.5 g / cm ³ or less, 2.45 g / cm ³ or less, 2.42 g / cm ³ or less, 2.40 g / cm ³ or less, 2 .38g / cm ³ or less, 2.35 g / cm ³ or less, particularly preferably 2.34 g / cm ³ or less. When the density is larger than 2.6 g / cm ³ , it is difficult to reduce the weight of the glass film. Here, “density” refers to a value measured by the well-known Archimedes method.

In the glass film of the present invention, the thermal expansion coefficient is 25 to 50 × 10 ⁻⁷ / ° C., 29 to 45 × 10 ⁻⁷ / ° C., 31 to 39 × 10 ⁻⁷ / ° C., and 32 to 38 × 10 ⁻⁷ / ° C. 33 to 37 × 10 ⁻⁷ / ° C., particularly 33 to 35 × 10 ⁻⁷ / ° C. is preferable. When the thermal expansion coefficient is outside the above range, the glass film tends to warp due to a difference in thermal expansion coefficient from a film such as a TFT. In addition, a glass film becomes easy to warp, so that film thickness is small. Therefore, the smaller the film thickness, the higher the necessity of regulating the thermal expansion coefficient within the above range.

  In the glass film of the present invention, the strain point is preferably 500 ° C. or higher, 550 ° C. or higher, 620 ° C. or higher, 630 ° C. or higher, 640 ° C. or higher, 650 ° C. or higher, and particularly 660 ° C. or higher. When the strain point is low, when the glass film is used for an organic EL display substrate, the glass film is likely to be thermally contracted in the manufacturing process of the p-Si • TFT.

High temperature melting increases the burden on the glass melting furnace. Refractories such as alumina and zirconia used in a glass melting furnace are eroded violently by molten glass as the temperature rises. When the erosion amount of the refractory is increased, the life cycle of the glass melting furnace is shortened, and as a result, the manufacturing cost of the glass film is increased. In addition, when performing high temperature melting, it is necessary to use a high heat resistance component for the glass melting kiln, so the glass melting kiln becomes expensive, resulting in a high glass melting cost. . Furthermore, high-temperature melting requires that the interior of the glass melting furnace be maintained at a high temperature, so that the running cost is higher than that at low-temperature melting. Therefore, in the glass film of the present invention, the temperature at 10 ^2.5 dPa · s is preferably 1590 ° C. or lower, 1580 ° C. or lower, 1570 ° C. or lower, 1560 ° C. or lower, particularly 1550 ° C. or lower. When the temperature at 10 ^2.5 dPa · s is higher than 1590 ° C., low-temperature melting becomes difficult, and the bubble quality tends to be lowered, and as a result, the production cost of the glass film is likely to increase. Here, “temperature at 10 ^2.5 dPa · s” corresponds to the melting temperature and indicates a value measured by a platinum ball pulling method.

  In the glass film of the present invention, the liquidus temperature is preferably 1180 ° C. or lower, 1150 ° C. or lower, 1110 ° C. or lower, 1070 ° C. or lower. In this way, devitrification crystals are less likely to occur in the glass, and it becomes easier to form the glass by the overflow downdraw method or the like. For this reason, the manufacturing cost of a glass film can be reduced, improving the surface quality of a glass film. The liquidus temperature is an index of devitrification resistance. The lower the liquidus temperature, the better the devitrification resistance.

In the glass film of the present invention, the liquid phase viscosity is 10 ^4.5 dPa · s or more, 10 ^5.0 dPa · s or more, 10 ^5.5 dPa · s or more, 10 ^5.7 dPa · s or more, particularly 10 ^{5. .8} dPa · s or more is preferable. In this way, since devitrification crystals are less likely to occur during molding, it becomes easier to mold glass by the overflow down draw method or the like, and the glass film manufacturing cost is reduced while improving the surface quality of the glass film. be able to. The liquid phase viscosity is an index of moldability. The higher the liquid phase viscosity, the better the moldability.

  The glass film of the present invention is preferably formed by an overflow downdraw method. In this way, a glass film that is unpolished and has good surface quality can be produced. The reason is that, in the case of the overflow downdraw method, the surface to be the surface of the glass film does not come into contact with the bowl-like refractory and is molded in a free surface state. The structure and material of the bowl-shaped structure are not particularly limited as long as desired dimensions and surface quality can be realized. Moreover, in order to perform the downward extending | stretching shaping | molding, the method of applying force with respect to a glass film will not be specifically limited if a desired dimension and surface quality are realizable. For example, a method may be adopted in which a heat-resistant roll having a sufficiently large width is rotated and stretched in contact with the glass film, or a plurality of pairs of heat-resistant rolls are only near the end face of the glass film. You may employ | adopt the method of making it contact and extending | stretching. The lower the liquidus temperature and the higher the liquidus viscosity, the easier it is to mold the glass film by the overflow downdraw method.

  Various molding methods can be applied to the glass film of the present invention in addition to the overflow downdraw method. For example, a slot down draw method, a redraw method, or the like can be applied.

  In the glass film of the present invention, the surface roughness Ra is 50 Å or less, 30 Å or less, 10 Å or less, 5 Å or less, 3 Å or less, 2 Å or less. When the surface roughness Ra is increased, the quality of a film such as ITO or TFT formed on the glass film is lowered, and the device may cause a display defect. Here, “surface roughness (Ra)” refers to a value measured by a method based on JIS B0601: 2001.

  In the glass film of the present invention, a glass batch prepared so as to have a predetermined glass composition is put into a continuous glass melting furnace, and after the glass batch is heated and melted, the obtained molten glass is clarified and put into a molding apparatus. It can be manufactured by forming into a thin plate shape after being supplied.

  Hereinafter, based on an Example, this invention is demonstrated in detail.

  Table 1 shows examples of the present invention (sample Nos. 1 to 10).

Sample no. 1-10 were produced. First, a glass batch prepared so as to have the glass composition shown in the table was put in a platinum crucible, melted at 1600 ° C. for 24 hours, and then poured out onto a carbon plate to form a flat plate shape. Next, for each sample obtained, dielectric constant, dielectric loss tangent, the density, the thermal expansion coefficient alpha, strain point, annealing point, softening ^point, temperature at ^{10 4.0 dPa · s, 10 3.0} dPa · s at a ^temperature, temperature at ¹⁰ 2.5 dPa · s, the liquid phase temperature TL, to evaluate the liquidus viscosity LogitaTL.

  The dielectric constant and dielectric loss tangent are measured values at a frequency of 1 MHz and 25 ° C. in accordance with ASTM D150.

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

  The thermal expansion coefficient α is a value measured with a dilatometer, and is an average value in a temperature range of 30 to 380 ° C.

  The strain point, annealing point, and softening point are values measured based on the method of ASTM C336.

The temperature at 10 ^4.0 dPa · s, the temperature at 10 ^3.0 dPa · s, and the temperature at 10 ^2.5 dPa · s are values measured by the platinum ball pulling method.

  The liquid phase temperature TL passes through a standard sieve 30 mesh (500 μm), and the glass powder remaining in 50 mesh (300 μm) is placed in a platinum boat and held in a temperature gradient furnace for 24 hours to measure the temperature at which crystals precipitate. It is the value.

  The liquid phase viscosity log ηTL is a value obtained by measuring the viscosity of the glass at the liquid phase temperature TL by the platinum pulling method.

As is clear from Table 1, sample No. In Nos. 1 to 10, since the glass composition is regulated within a predetermined range, the dielectric constant is 4.93 or less, the dielectric loss tangent is 0.0007 or less, the density is 2.39 g / cm ³ or less, and the thermal expansion coefficient α is 30 to 30. 35 × 10 ⁻⁷ / ° C., strain point was 511 ° C. or higher, temperature at 10 ^2.5 dPa · s was 1548 ° C. or lower, liquidus temperature TL was 1190 ° C. or lower, and liquidus viscosity logηTL was 4.0 or higher. . Sample No. 1-10, but it does not contain _{As 2 O 3, Sb 2 O} 3 in the glass composition, the foam quality was good.

  In the test melting furnace, sample No. When 1-4 was melted and a glass film having a film thickness of 50 μm was formed by the overflow downdraw method, the surface roughness (Ra) was 20 mm or less. In forming the glass film, the speed of the pulling roller, the speed of the cooling roller, the temperature distribution of the heating device, the temperature of the molten glass, the flow rate of the molten glass, the drawing speed, the rotation speed of the stirring stirrer, etc. are appropriately adjusted. The surface quality of the was adjusted. “Surface roughness (Ra)” is a value measured by a method based on JIS B0601: 2001.

  In the test melting furnace, sample No. 1 to 10 were melted, and a glass film having a film thickness of 30 μm was formed by the overflow downdraw method or the redraw method. Next, the obtained glass film is irradiated with an Nd: YAG laser to form a through hole having a diameter of 30 μm, and further, the through hole is subjected to aluminum plating so that conduction is established between the front surface and the back surface of the glass film. Processing was performed so that it could be removed. Subsequently, a wiring pattern such as an electrode was formed on the front surface of the glass film. Finally, a plurality of patterned glass films were prepared and laminated to prepare a wiring board.

Claims (9)

  A glass film having a film thickness of 100 μm or less, a dielectric constant at a frequency of 1 MHz of 5 or less, and a dielectric loss tangent at a frequency of 1 MHz of 0.5 or less. As a glass composition, in _{mass%, SiO 2 40~80%, Al} 2 O 3 0~20%, B 2 O 3 10~30%, 0~10% MgO, CaO 0~10%, SrO 0~10% BaO 0 to 10% is contained, The glass film of Claim 1 characterized by the above-mentioned. As a glass composition, in _{mass%, SiO 2 55~75%, Al} 2 O 3 10~20%, B 2 O 3 13~30%, 0~4% MgO, CaO 1~10%, SrO 0~5% , BaO _{0 to 5%,} the glass film according to claim 1, characterized in _{that Li 2 O + Na 2 O +} K 2 O containing 6%. As a glass composition, in _{mass%, SiO 2 55~63%, Al} 2 O 3 10~20%, B 2 O 3 13~20%, 0~2% MgO, CaO 6~10%, SrO 0~3% glass film according to claim 1, wherein BaO 0~3%, MgO + CaO + SrO + BaO 6.5~10%, by containing _{Li 2 O + Na 2 O +} K 2 O 0~0.1%. The thermal expansion coefficient is 25-50 * 10 < ^-7 > / degreeC, The glass film in any one of Claims 1-4 characterized by the above-mentioned. Glass film according to claim 1, liquidus viscosity, characterized in that of ¹⁰ 4.0 dPa · s or more.   The glass film according to claim 1, wherein the glass film is formed by an overflow downdraw method.   It uses for the board | substrate of an organic electroluminescent display, The glass film in any one of Claims 1-7 characterized by the above-mentioned.   It uses for a wiring board, The glass film in any one of Claims 1-7 characterized by the above-mentioned.