JP2005008509A - Cover glass for optical semiconductor package, and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cover glass which has high weatherability and high surface strength that are required for the cover glass for an optical semiconductor package such as a solid imaging device because of the spread of its application, and to provide its production method. <P>SOLUTION: The cover glass for the optical semiconductor package contains, by mass, 50-70% SiO<SB>2</SB>, ≥0.1% Al<SB>2</SB>O<SB>3</SB>, and 5-20% B<SB>2</SB>O<SB>3</SB>and is characterized in that the ratio of Sn<SP>2+</SP>to the whole content of Sn is ≥0.15 in the glass, the surface roughness on the translucent surface is ≤0.5 nm, the α-ray emitting quantity is ≤0.5 c/cm<SP>2</SP>×hr, the amount of alkali elution is <0.3 mg, the density is ≤2.7 g/cm<SP>3</SP>, and the specific Young's modulus is ≥27 GPa/g×cm<SP>-3</SP>. The production method for the cover glass for the optical semiconductor package includes a glass raw material controlling process, a feeding process for feeding the controlled raw material into a heat resistant vessel, a melting process, and a processing process for processing a formed material after forming. In the method, tin oxide is added, and the cover glass contains Sn in an amount of 0.01-2.0 mass % expressed in terms of SnO<SB>2</SB>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cover glass that is attached as a window on a front surface of a package that houses an optical semiconductor element such as a solid-state imaging element or a laser diode, and protects the optical semiconductor element, and a method for manufacturing the same.

  In general, a solid-state imaging device used as an image sensor, or a light-emitting device such as a laser diode or a photocoupler, a light-receiving device, or an optical semiconductor device such as a light-receiving or light-emitting device is housed inside a package having an airtight structure, A cover glass made of flat glass having translucency is used. This cover glass is variously bonded to various package cases such as ceramic materials such as alumina, metal materials such as Kovar (Fe-Ni-Co alloy), composite materials such as glass epoxy substrate, and plastic materials such as epoxy resin. Sealed using an agent and used as a translucent window.

  Optical semiconductors used as solid-state imaging devices include CCDs (Charge Coupled Devices), CMOSs (Complementary Metal Oxide Semiconductors), and the like. Of these, CMOS was announced in 1967, three years earlier than CCD, but initially it was supposed to be inferior in image quality to CCD, but it was overcome by providing an amplifier for each pixel. A circuit for reducing noise called fixed pattern noise can be mounted, and the image quality has been improved in recent years. On the other hand, CMOS can be reduced in size compared with CCD, and power consumption is as low as about one-fifth, and the manufacturing process of the microprocessor can be used as it is. Advantages such as being capable of being manufactured are attracting attention, and they are increasingly mounted on image input devices such as mobile phones and portable information input terminals. Such a solid-state imaging device is required to have a package with a thinner structure by using a flip chip technique or the like as disclosed in Patent Document 1.

  In such CCDs and CMOSs, high-quality cleanliness and strict tolerance standards are required for foreign matter, dirt and scratches adhering to the surface of the cover glass because it is necessary to accurately convert fine images to electronic information. It has been. Moreover, not only the surface of the cover glass, but also prevention of contamination of foreign substances such as crystals and platinum in the glass, as disclosed in Patent Documents 2, 3, and 4, U (uranium) which is a trace amount of radioactive component in the glass, Various measures have been taken, such as the use of high-purity raw materials to prevent soft errors caused by alpha rays emitted from Th (thorium) and Ra (radium), and the quality of the cover glass for solid-state image sensors has been improved. It has been broken.

  In addition, as a laser diode, generally, a molded body made of various alloys such as Kovar, 42 iron nickel alloy, 50 iron nickel alloy, and stainless steel is used, and its thermal expansion coefficient is slightly higher than the metal material of the molded body. A small cover glass is used as a cap material sealed as a translucent window with various sealing materials, and a package composed of the cap material is used.

And, as disclosed in Patent Document 5, the cover glass used as a light-transmitting window of the package that houses these optical semiconductor elements generally uses a high-purity glass raw material that is homogeneously mixed so as to have a desired mixing ratio. It is manufactured by heating to 1200 ° C. or higher in a heat-resistant container such as a high-purity platinum or SiO ₂ crucible and then molding and processing it into a desired shape.
JP 2002-43554 A JP-A-7-172868 Japanese Patent Application Laid-Open No. 6-121539 JP 7-215733 A JP-A-6-345480

  In recent years, in the field of solid-state imaging devices, a device that has been recognized to expand to new applications is CMOS. CMOS is often used for cellular phones, PDAs (Personal Digital Assistants) and the like because of the low cost of elements. Since these electronic devices are also used outdoors, they are lightweight and easy to carry, and at the same time, high weather resistance is required. Therefore, the cover glass for optical semiconductor packages used for such applications has high weather resistance in addition to the characteristics of being inexpensive and lightweight, and even when used in harsh outdoor environments, It is important to combine the characteristics that stable and accurate image information can be obtained without degrading the quality.

  However, since the conventional cover glass for optical semiconductor packages was not necessarily manufactured for outdoor use, when used in harsh environments for a long time, There has been a risk of problems in durability, particularly water resistance. Further, as described above, the thickness of the package for the solid-state imaging device has been further reduced due to the influence of weight reduction and higher integration of electronic devices, and accordingly, the thickness of the cover glass has also been reduced. There is an increased risk and risk that fine scratches generated on the surface of the cover glass lead to breakage of the solid-state imaging device or failure of the electronic device.

  In view of such circumstances, the present inventors have become necessary as the cover glass for optical semiconductor packages used for solid-state imaging devices and the like, in addition to various properties that have been required so far, with the recent expansion of applications. The present invention invents and provides a cover glass for an optical semiconductor package having both high weather resistance and strength characteristics against the glass surface deflection and the like, and a method for producing the same.

That is, in order to solve the above-mentioned problem, the cover glass for optical semiconductor packages of the present invention is a cover glass for optical semiconductor packages made of inorganic oxide glass, and the Sn component is 0.02 to 2.0 mass% in terms of SnO _2. It is characterized by containing.

Here, in the cover glass for optical semiconductor packages made of inorganic oxide glass, containing 0.02 to 2.0% by mass of Sn component in terms of SnO ₂ means that Sn (tin) contained as the glass composition of the cover glass. ) In the range of 0.02% to 2.0% in terms of mass ratio when converted to stannic oxide which is an oxide.

Sn in the glass can be evaluated in the water resistance of the cover glass surface, especially in environmental tests, in addition to the function as a fining agent added to remove bubbles that become defects due to remaining in the cover glass. It has a function to improve long-term durability, and is necessary to realize the performance that can withstand harsh humidity environment over time when the cover glass is mounted on an electronic device used outdoors etc. It is an ingredient. Then, the content thereof is required to be at least as SnO ₂ or 0.02 mass%. Furthermore, in order to exhibit a stable effect, it is better to add SnO ₂ in an amount of 0.03% by mass or more.

On the other hand, although it depends on the amount of bubbles generated in the molten glass, it is preferable to add 0.05% by mass or more as SnO ₂ for clarification performance, and even if the glass has a large number of bubbles, reliable clarification is realized. Requires 0.08% by mass or more. Then, in order to achieve higher environmental resistance is necessary to add more than 0.1% by mass as SnO _2, more preferably better to 0.12 mass% or more. On the other hand, if adding over 2.0% by mass as SnO ₂ , there are too many bubbles such as oxygen bubbles at the time of melting, so that it becomes difficult to sufficiently degas after that, and there is a possibility that the clarification may be hindered. Is not preferable. And in the case of glass with a high volatile component content that requires low-temperature clarification, the amount of SnO ₂ added to generate a large number of bubbles should be limited, and the upper limit is 1.9% by mass. Is good.

  In addition, for Sn, during melting, the Sn component forms an alloy with Pt used in a heat-resistant part of a melting apparatus such as a melting container, and becomes brittle, which may damage the container and the apparatus. If the upper limit of addition is further set from the viewpoint, it is preferably up to 1.5% by mass, and more preferably 1.3% by mass in order to use the peripheral device for a long period of time more reliably.

In addition to the above, the cover glass for an optical semiconductor package of the present invention has a Sn ²⁺ / total Sn ratio of 0.15 or more in the glass and contains 50 to 70% by mass of Si component in terms of SiO _2. And, the Al component is contained in an amount of 0.1% by mass or more in terms of Al ₂ O ₃ .

Here, the ratio of Sn ²⁺ / total Sn in the glass is 0.15 or more, the Si component is contained in an amount of 50 to 70% by mass in terms of SiO ₂ , and the Al component is 0.1 in terms of Al ₂ O _3. “Mass% or more” means that the content of divalent tin in all Sn contained in the glass is 15% or more, and this glass has a silicon component in terms of silicon dioxide (silica) as its composition. Means that the aluminum component is contained in an amount of 0.1% by mass or more in terms of aluminum oxide (alumina).

Sn exists as a divalent cation (Sn ²⁺ ) and a tetravalent cation (Sn ⁴⁺ ) in molten glass, but its equilibrium state is divalent on the high temperature side and tetravalent on the low temperature side. In order to change, by utilizing this valence change, oxygen bubbles can be foamed and a clarification effect can be realized. In this case, in order to realize a sufficient clarification effect, the ratio of Sn ²⁺ / total Sn is preferably 0.15 or more. In order to achieve higher fining performance, the Sn ²⁺ / total Sn ratio should be 0.18 or higher, and 0.21 or higher to achieve a more stable function. Is more preferable. In addition, the environmental resistance performance of the cover glass also has high chemical durability when the ratio of Sn ²⁺ / total Sn is 0.15 or more. In order to achieve higher performance, this ratio is preferably 0.23 or more.

About Si component, it is a main component used as the frame | skeleton which comprises glass, and is a component which contributes to the improvement of the weather resistance of glass. When the content of SiO ₂ is less than 50% by mass, the use of solid-state imaging devices, particularly those mounted on electronic devices used outdoors such as portable information terminals typified by mobile phones are long-term From the standpoint of maintaining excellent performance, it is not preferable because a problem may occur with respect to the weather resistance of the cover glass. On the other hand, if the content of SiO ₂ exceeds 70% by mass, it becomes difficult to melt the glass raw material homogeneously to obtain a high-quality glass product, and expensive melting equipment is required to overcome this problem. Therefore, it is not realistic because it leads to an increase in manufacturing cost and, in turn, an increase in product cost. The more preferable content of SiO ₂ is 53 to 69% by mass, and the more preferable content is 55 to 69% by mass.

On the other hand, the Al component is also a component that contributes to improving the weather resistance of the cover glass, and the content thereof is required to be at least 0.1% by mass or more. In particular, when water resistance is required from the use of a cover glass, addition of 0.5% by mass or more in terms of Al ₂ O ₃ is preferable. In order to achieve higher performance, the addition amount is preferably 1.5% by mass or more in terms of Al ₂ O ₃ and more preferably 3.0% by mass or more. It becomes.

In addition to the above, the cover glass for an optical semiconductor package of the present invention contains 5 to 20% by mass of B component in terms of B ₂ O ₃ and 0.1 to 19% by mass of Al component in terms of Al ₂ O _3. % Content.

Here, the B component contains 5 to 20 wt% in terms _of B ₂ O _3, and to what the Al component containing 0.1 to 19 wt% in terms of Al ₂ O _3, containing the B component in the cover glass In addition to the amount being 5 to 20% by mass in terms of boron dioxide, it means that the aluminum component is contained in an amount of 0.1 to 19% by mass or more in terms of aluminum oxide (alumina).

Component B is useful as a component that acts as a flux during glass melting, lowers the viscosity of the molten glass, and improves the meltability of the glass. When the B component is less than 5% by mass in terms of B ₂ O ₃ , the function as a flux at the time of melting the glass becomes insufficient, and the glass tends to be inhomogeneous. On the other hand, when it is more than 20% by mass in terms of B ₂ O ₃ , the weather resistance, particularly water resistance of the glass tends to be lowered. And more preferred content of component B 6-16% by mass in terms _of B ₂ O _3, more preferably from 7 to 16 mass% in terms _of B ₂ O _3, more preferably in terms _of B ₂ O ₃ 7-14 % By mass.

In addition, as described above, the Al component also contributes to improving the weather resistance of the cover glass. However, when the content in terms of Al ₂ O ₃ exceeds 19% by mass, the initial melting property of the glass is reduced when the glass raw material is melted. As it becomes worse, the production of homogeneous glass products is often hindered. As a result, in actual use as a cover glass for optical semiconductor packages, the optical characteristics and mechanical performance tend to be hindered. Moreover, the more preferable content in terms of Al ₂ O ₃ of the Al component is 0.1 to 17% by mass, or 0.1 to 15% by mass, and the more preferable content is 1.5 to 15% by mass.

In addition to the above, the cover glass for optical semiconductor packages of the present invention is SiO ₂ 50 to 70%, Al ₂ O ₃ 0.1 to 15%, B ₂ O ₃ 7 to 16%, BaO + SrO + MgO + CaO + ZnO 0 in addition to the above. It has a composition of 0.5 to 25% and SnO ₂ 0.03 to 1.9%.

Here, mass% SiO ₂ 50-70% by _{display, Al 2 O 3 0.1~15%,} B 2 O 3 7~16%, BaO + SrO + MgO + CaO + ZnO 0.5~25%, SnO 2 0.03~1. Having a composition of 9% means that the glass composition of the cover glass is expressed in terms of oxides of the respective components, SiO ₂ is in the range of 50 to 70% by mass, and Al ₂ O ₃ is 0.1 to 15 0.5 to 25% by mass as a total amount of oxide of each component in the range of mass%, B ₂ O _{3 in} the range of 7 to 16% by mass, and alkaline earth metal (Ba, Sr, Mg, Ca, Zn) , Which means 0.03 to 1.9% by mass as stannic oxide.

As for the Al component and the B component, when the optimum component ranges are limited as described above, the Al ₂ O ₃ content is 0.1 to 15% and the B ₂ O ₃ content is 7 to 16%. Moreover, each component which is alkaline-earth metal (Ba, Sr, Mg, Ca, Zn) improves the meltability of glass by reducing the viscosity of glass while improving the weather resistance of glass, and homogenizes. It is a component having an effect that greatly contributes to the above. When the total alkaline earth metal oxide content is less than 0.5% by mass, the above effect cannot be obtained sufficiently, and conversely, the alkaline earth metal oxide content is 25% by mass. If it exceeds 1, the glass's devitrification tendency increases, so that the transmittance of the glass may decrease, or the homogeneity of the glass product may decrease, leading to a decrease in strength. Moreover, since the density of glass becomes high, so that content of alkaline-earth metal oxide increases, when the cover glass is reduced in weight, it is better.

In addition to the above, the cover glass for optical semiconductor packages of the present invention is SiO ₂ 55 to 69%, Al ₂ O ₃ 1.5 to 15%, B ₂ O ₃ 7 to 16%, MgO 0 in terms of mass%. It is characterized by having a composition of ˜5%, CaO 0-10%, BaO 0-12%, SrO 0-10%, CaO + BaO + SrO + ZnO 0.3-13%, SnO ₂ 0.03-1.9%.

Here, SiO ₂ fifty-five to sixty-nine% represented by _{mass%, Al 2 O 3 1.5~15%,} B 2 O 3 7~16%, 0~5% MgO, CaO 0~10%, BaO 0~12 %, SrO 0 to 10%, BaO + SrO + ZnO 0.3 to 13%, SnO ₂ 0.03 to 1.9% means that the glass composition of the cover glass is expressed in terms of oxide of each component. And SiO ₂ is in the range of 55 to 69% by mass, Al ₂ O ₃ is in the range of 1.5 to 15% by mass, B ₂ O ₃ is in the range of 7 to 16% by mass, and MgO is in the range of 0 to 5% by mass. Range, CaO in the range of 0 to 10% by mass, BaO in the range of 0 to 12% by mass, SrO in the range of 0 to 10% by mass, and the total amount of BaO, SrO and ZnO in the range of 0.3 to 13% by mass , Meaning that SnO ₂ is in the range of 0.03 to 1.9% by mass is doing.

As described above, the optimum component range for the B component is 7 to 16% by mass in terms of B ₂ O ₃ , but the Si component and Al component also have water resistance, acid resistance, and JIS-R3502. If it is necessary to obtain a higher performance with respect to the value of the alkali elution amount specified in Fig. 5 and to achieve a material that can be produced at low cost by realizing high solubility of the raw material, the range is SiO ₂ 55-69 mass. %, Al ₂ O ₃ 1.5 to 15% by mass.

  And as content of the above-mentioned alkaline earth metal, in addition to weather resistance, the density and specific Young's modulus can also be set to a desired performance, that is, the density is low, and the Young's modulus can be set to a sufficiently high value for practical use. If limited to the glass composition range, MgO 0-5%, CaO 0.3-10%, BaO 0-12%, SrO 0-10%, CaO + BaO + SrO + ZnO 0.3-13% in mass% are better. .

  And especially about the Ca component, it is an important component for stabilizing the weather resistance of the cover glass. However, if the content of the Ca component exceeds 10% by mass, a non-homogeneous dissolution state occurs at the initial stage of glass melting. For this reason, there may be a case where defective products are generated due to mixing of fine dissolved residual foreign matters into the molded product. Therefore, the Ca component is preferably 10% by mass or less in terms of CaO. More preferably, it is better to add Ca component in terms of oxide, that is, CaO as 0.1% by mass or more, more preferably as CaO, 0.3% by mass or more as CaO. It is to be.

  Furthermore, about the total amount of CaO + BaO + SrO + ZnO, it is possible to quickly dissolve the glass raw material by adopting a composition within the range of 0.3 to 13% by mass, that is, 0.3% by mass or more, and 13% by mass. By making the range not to exceed%, it becomes possible to suppress the scattering of the mixed raw material at the time of melting the glass raw material. Therefore, defining the total amount of CaO + BaO + SrO + ZnO to 0.3 to 13% by mass is preferable from the viewpoint of the sanitary environment around the glass melting equipment in addition to increasing the durability of the glass melting equipment. The total amount of CaO + BaO + SrO + ZnO is more preferably 0.5 to 13% by mass.

  In addition to the above, the cover glass for an optical semiconductor package of the present invention is made of alkali-free glass.

  Here, the alkali-free glass means a glass that essentially does not contain alkaline elements Li, Na, and K. That is, the inclusion of these alkali elements in the order of ppm mixed in the glass as impurities corresponds to a substance not substantially contained. It is because it is better not to mix an alkali element if possible, in order to satisfy the high weather resistance at the time of use of the cover glass of this invention, consisting of an alkali free glass. Also, the case where the cover glass is sealed with resin is not preferable because an alkali element from the glass surface may cause deterioration of the resin over time.

  Moreover, the cover glass for optical semiconductor packages of this invention contains 0.1-15 mass% of alkali metal elements in the total amount of oxide conversion in addition to the above.

Here, containing an alkali metal element in an amount of 0.1 to 15% by mass in terms of oxide means that Li, Na, and K are Li ₂ O and Na ₂ as the composition of the cover glass. This means that the total content of O and K ₂ O is 0.1 to 15% by mass. This is, as explained in the alkali-free glass, even if it is better to have as little alkali content as possible, high temperature is necessary for the glass melting condition for that, and the burden on the production equipment accompanying it is large, To overcome this, expensive equipment is required. In order to avoid such a situation, when it is possible to contain an alkali metal element in an amount of 0.1 to 15% by mass in terms of oxide, it is a suitable choice, and in particular, there is a demand for the cover glass of the present invention. This is preferable when production corresponding to the above is performed. Therefore, when the allowable range of production equipment and the like is expanded, the alkali metal element is preferably 0.1 to 12% by mass, more preferably 0.1 to 11% by mass in terms of oxide.

  In addition to the above, the cover glass for optical semiconductor packages of the present invention is characterized in that the surface roughness of the translucent surface is 0.5 nm or less in terms of Ra value.

  Here, the surface roughness of the light-transmitting surface is 0.5 nm or less in terms of Ra value. The surface roughness of the two light-transmitting surfaces having the maximum area of the cover glass is 0.5 nm or less. I mean. Ra conforms to the standard of JIS-B0601 (1994).

  If the surface roughness of the translucent surface exceeds 0.5 nm, there may be a problem in terms of strength with respect to the cover glass for translucent windows of packages that are mounted on electronic devices used outdoors and that store optical semiconductors. It is difficult to achieve a long-term stable strength grade. Therefore, the surface roughness of the translucent surface is preferably 0.4 nm or less, and more preferably 0.3 nm or less in order to obtain a more stable quality.

  Moreover, the cover glass for optical semiconductor packages of the present invention having the above-described configuration has various dimensions such as an outer dimension of 2 to 50 mm in length, 2 to 50 mm in width, and a thickness of 0.1 to 1 mm. The surface is in a mirror state. Further, no foreign matter, bubbles or the like are observed inside the glass of the light transmitting surface, and the color tone due to the transmitted light in the thickness direction is colorless. The end surface of the cover glass of the present invention may be a ground surface, but is preferably a mirror surface for preventing dust generation, a mirror surface by polishing finish, a mirror surface formed by acid treatment such as HF, and cleaving. There is no problem even if the surface is cleaved or a mirror surface obtained by low-temperature press molding.

In addition to the above, the cover glass for optical semiconductor packages of the present invention is characterized in that the α-ray emission amount is 0.5 c / cm ² · hr or less.

As the cover glass of the present invention, U (uranium), Th (thorium), Ra (radium), Fe ₂ O are used by adopting a high-purity raw material and its maintained melting environment while having the above-mentioned characteristics. ₃ , PbO, TiO ₂ , MnO ₂ , ZrO _{2, and the} like are precisely controlled, and particularly for Fe ₂ O ₃ , PbO, TiO ₂ , and MnO ₂ that affect the transmittance in the vicinity of ultraviolet rays, It is preferable to be managed in the order of 1 to 100 ppm. With this, it is possible to manage U, Th, and Ra that cause a CCD soft error due to α rays in the order of 0.1 to 10 ppb. It has become. And from such a point, it is necessary that the α-ray emission amount of the package cover glass is 0.5 c / cm ² · hr or less.

  In addition to the above, the cover glass for an optical semiconductor package of the present invention has an alkali elution amount specified in JIS-R3502 of less than 0.3 mg, an acid resistance specified in JIS G06 of less than 0.2%, and water resistance. The property is less than 0.2%.

  Here, the alkali elution amount of the standard of JIS-R3502 is less than 0.3 mg, the acid resistance of the standard of JOGIS06 is less than 0.2%, and the water resistance is less than 0.2%. Also represents the weather resistance grade of the cover glass. The alkali elution amount of the standard of JIS-R3502 is measured when the alkali elution amount from the cover glass for a package of the present invention is measured by applying a test method based on Japanese Industrial Standard (JIS-R3502-1995). It means that the value is less than 0.3 mg. As a quality for realizing more stable weather resistance, the alkali elution amount is preferably 0.2 mg or less.

  The acid resistance and water resistance of the JOGIS06 standard are determined by the Japan Optical Glass Industry Association Standard (JOGIS06-1999). It is immersed in 80 ml of 0.01N nitric acid in a round bottom flask with a glass cooler for 60 minutes, heated in boiling water for 60 minutes, weighed after drying at 120 ° C, and the weight loss rate is less than 0.2%. Represents. In addition, the water resistance was immersed in 80 ml of pure water (pH 6.5 to 7.5) with the same apparatus, heated in boiling water for 60 minutes, dried at 120 ° C., weighed, and the weight loss rate was 0.00. It represents less than 2%. As the quality for realizing more stable weather resistance, it is preferable that the acid resistance is less than 0.1% and the water resistance is less than 0.1%.

In addition to the above, the cover glass for an optical semiconductor package of the present invention is characterized by having a density of 2.7 g / cm ³ or less and a specific Young's modulus of 27 GPa / g · cm ⁻³ or more.

Here, the density of the cover glass being 2.7 g / cm ³ or less means that the weight of the cover glass for the solid-state image sensor is as light as possible in electronic devices that are frequently carried, such as mobile phones. Therefore, it is suitable for such a use.

Further, depending on the portable electronic device to be mounted, the cover glass may require high strength, and Young's modulus is one index representing the strength. Since the Young's modulus represents the amount of deformation when the cover glass is loaded with a constant external force, the cover glass becomes difficult to deform as the Young's modulus increases. Therefore, by setting the specific Young's modulus (that is, Young's modulus / density) to 27 GPa / g · cm ⁻³ or more, it satisfies both of the two characteristics of being lightweight and difficult to deform, and is suitable for portable electronic devices. It will be something.

  The cover glass for an optical semiconductor package of the present invention is characterized in that, in addition to the above, the optical semiconductor is a solid-state imaging device and is used for a package for housing it.

  Here, the solid-state imaging device is classified into the interline transfer type (IT-CCD), the frame interline transfer type (FIT-CCD), the full frame transfer type (FF-CCD), which are classified according to the difference between the light receiving method and the transfer method. The frame transfer type (FT-CCD), photoconductive film stack type (PSD), etc. are included without distinction, and the cover glass of the present invention can be applied, and further classified into CMOS and other solid-state imaging devices. The cover glass of the present invention can also be used for a storage package of an element used in this field. In particular, the cover glass of the present invention is suitable as a cover glass for an element storage package used in a digital camera, a mobile phone, etc., such as an interline transfer type (IT-CCD) and a progressive scan type CCD included therein. It is.

  In addition to the above, the cover glass for an optical semiconductor package of the present invention is characterized in that the optical semiconductor is a CMOS, and is used for a package for housing it.

  Here, the CMOS is an element that can be used with low power consumption as described above, and that is smaller and more compact than a CCD. Therefore, the cover glass of the present invention has characteristics suitable for use in such a small element.

  The cover glass for an optical semiconductor package of the present invention is characterized in that, in addition to the above, the optical semiconductor is a laser diode, and is used for a package for housing the laser diode.

  Here, being used in a package for storing a laser diode means that a resin or the like is applied around a cover glass formed into a plate shape for a window of the laser diode, thereby opening the cap material of the laser diode. It means that it is sealed and used.

  The cover glass of the present invention has the properties required as a window material for a laser diode as described above, and has high transmittance for desired visible light, infrared light, and ultraviolet light, The cover glass has stable weather resistance and high practical strength, and is suitable as a window material for a laser diode.

  Further, the cover glass for a solid-state imaging device of the present invention having the above configuration has various dimensions of, for example, 2 to 50 mm in length, 2 to 50 mm in width, and 0.05 to 1 mm in thickness, and the light-transmitting surface is a mirror surface. Presents a condition. Further, no foreign matter, bubbles or the like are observed inside the glass, and the color tone due to the transmitted light in the thickness direction is colorless.

  The cover glass according to the present invention can also be used as a thin glass for filters by adding a predetermined amount of a transition metal element at a predetermined concentration or by precipitating a noble metal element or the like in a colloidal state. In addition, it can also be used for electronic equipment used in optical functional parts. Furthermore, it is possible to impart necessary optical characteristics by applying a deposited film or the like to the surface of the flat glass by various methods such as CVD.

The method for producing an optical semiconductor package cover glass according to the present invention includes a step of mixing glass raw materials to prepare a glass raw material preparation, a step of introducing the glass raw material preparation into a heat resistant container, and the heat resistance A method of manufacturing a cover glass for an optical semiconductor package in which a glass raw material composition is melted into a molten glass in a container and the molten glass is formed into a predetermined shape and then processed into a plate having a desired size. In addition, the glass raw material preparation contains Sn oxide added as a fining agent, contains 0.02 to 2.0% by mass of Sn component in terms of SnO ₂ , and the ratio of Sn ²⁺ / total Sn is 0. Obtaining the plate-like glass having a thickness of 15 or more.

  Here, melting a glass raw material formulation to which Sn oxide is added as a fining agent means that when preparing a glass raw material formulation in which a plurality of raw materials are weighed and homogeneously mixed so as to have a desired composition, the glass This means that Sn oxide is added when the raw material mixture is prepared, and then the melting operation is performed in a heat-resistant container using a melting apparatus such as a melting furnace.

And obtaining 0.02 to 2.0% by mass of Sn component in terms of SnO ₂ and obtaining a plate-like glass having a Sn ²⁺ / total Sn ratio of 0.15 or more means melting the glass. In the process, by making the amount of heat received by the molten glass as high as necessary, Sn oxide added to the glass raw material preparation in advance is uniformly dispersed in the molten glass and lost due to volatilization from the molten glass, etc. By suppressing the amount of Sn to the minimum, the Sn component is 0.02 to 2.0% by mass in terms of SnO ₂ , and the ratio of divalent Sn to the total Sn is 0.15. It means to do so. Specifically, in order to make the amount of heat received by the molten glass as high as necessary, means such as sufficiently increasing the melting time or raising the glass melting temperature can be used. Moreover, in order to improve the homogeneity at the time of glass melting, use of various stirring devices etc. should naturally be performed.

  Moreover, the manufacturing method of the cover glass for optical semiconductor packages of this invention is characterized by not using an As component as a clarifier in addition to the above.

  Here, not using the As component as a fining agent means that the As component that has been frequently used so far is essentially not used as the fining agent of the cover glass for semiconductor element storage package windows. Therefore, any arsenic compound is not allowed. Even in applications other than the refining agent, the As component needs to be handled with care, and therefore, this is avoided as much as possible in the production of the cover glass for a semiconductor element storage package window of the present invention.

Moreover, the manufacturing method of the cover glass for optical semiconductor packages of this invention mixes a glass raw material in the container whose content of any one or more component of U, Th, Ra is 0.01 ppm or less in addition to the above. From the glass of the plate-shaped body by adjusting the raw material composition and melting it by putting it in a heat-resistant container made of SiO ₂ and / or Pt-containing heat-resistant container while holding the glass raw material composition in the container The amount of α-ray emission is 0.5 c / cm ² · hr or less.

  Here, adjusting the glass raw material mixture by mixing the glass raw material in a container having a content of one or more of U, Th, Ra of 0.01 ppm or less is a high-purity raw material as a glass raw material However, when a plurality of raw materials are weighed and mixed for a predetermined time, U, Th, and Ra that emit alpha rays to the material used in the container are 0.01 ppm (ppb In other words, if the content exceeds 10 ppb), the raw material after the mixing operation may be contaminated with U, Th, and Ra. Therefore, it means that U, Th, and Ra are 0.01 ppm or less (10 ppb or less) in the material in the container. If more stable quality is desired, 0.005 ppm (5 ppb or less) is more preferable.

Moreover, the amount of alpha rays emitted from the glass of the plate-like body can be reduced by charging it into a heat-resistant container made of SiO ₂ and / or Pt-containing heat-resistant container while holding the glass raw material composition in the container. If it is 0.5 c / cm ² · hr or less, the glass raw material after the mixing operation may be transferred from the container to another container, or may be kept and stored as it is. When the raw material is melted by connecting the container that was used for storage after storage to the raw material charging device and charging the glass raw material into the heat-resistant container heated to the high temperature state of the melting device. It means that the storage container connected to the charging device is a clean container having a U, Th, and Ra content of 0.01 ppm or less (10 ppb or less) as in the case of the mixing container. And if further stable quality is required for this container, it is more preferable to set it to 0.005 ppm (5 ppb or less). By realizing such an environment, the amount of α rays emitted from the glass sheet can be reduced to 0.5 c / cm ² · hr or less.

And for SiO ₂ and platinum crucibles used as heat-resistant containers for melting devices, since mixing of U, Th, Ra becomes a problem when melting glass, Similar high purity is required. For these containers, attention was often paid only to the melting container, but due to the downsizing of the melting equipment in recent years, the area of the wall surface of the melting container that comes into contact with the glass at the time of melting is relatively small. More attention must be paid to storage containers and mixing containers. For this reason, it is necessary to carry out production in a situation where the cleanliness of the storage container and the mixing container is improved, and at the same time, the components contained therein are also restricted.

  In addition to the above, for storage containers and mixing containers, common precautions include moisture contamination, segregation of Sn raw materials, and segregation. In addition, it is necessary to pay sufficient attention to segregation associated with vibrations when the storage period is long or when moving from the storage place or the mixing place to the melting place.

  In addition, as long as the above points are taken into account, as a charging method into the heat-resistant container of the melting apparatus, any charging method such as a screw feeder, a vibration feeder, a blanket feeder, an oscillation feeder, etc. may be adopted. Since there is no hindrance, the raw material composition to be input may be changed as necessary.

  Moreover, the manufacturing method of the cover glass for optical semiconductor packages of this invention is characterized by using the apparatus which employ | adopted the shaping | molding means which carries out an extending | stretching downward downward in addition to the above.

  Here, using an apparatus that employs a molding means that stretch-forms downward means that a molding method such as an overflow down-draw method, a slot-down draw method, or a roll-out down-draw method is suitable as a method for molding the glass after melting. Means. By adopting these molding methods, it is possible to produce a thin glass plate with good surface accuracy. And by adopting such a forming means, it is possible to easily realize the quality that the surface roughness of the light transmitting surface is 0.5 nm or less in terms of Ra value.

(1) As described above, the cover glass for optical semiconductor packages of the present invention contains 0.02 to 2.0% by mass of Sn component in terms of SnO ₂ in the cover glass for optical semiconductor packages made of inorganic oxide glass. When manufacturing cover glass, it is possible to easily remove the fine bubbles that become an obstacle from the glass. By reducing the rate, the manufacturing cost can be greatly reduced.

(2) In addition to the above, the cover glass for optical semiconductor packages of the present invention has a Sn ²⁺ / total Sn ratio of 0.15 or more in the glass, and the Si component is 50 to 70% by mass in terms of SiO _2. Since it contains 0.1% by mass or more of Al component in terms of Al ₂ O ₃ , the environmental durability such as water resistance of the cover glass surface is high, especially under the environment where the cover glass is used. Because it has high durability performance with respect to humidity, it improves the performance of the semiconductor storage package in which the cover glass is used, and makes it possible to use it stably for a long time without impairing the function of the stored semiconductor element. is there.

(3) Furthermore, the cover glass for optical semiconductor packages of the present invention contains 5 to 20% by mass of B component in terms of B ₂ O ₃ in addition to the above, and 0.1 to 0.1% in terms of Al ₂ O _3. Since it contains 19% by mass, in addition to high chemical durability, it has stable thermal characteristics that can sufficiently withstand the thermal history received in the semiconductor element assembly process such as thermal shock required as hard glass, A plurality of options can be considered as a sealing method at the time of package assembly, and a high-quality package can be assembled according to the function of the semiconductor to be stored.

(4) Further, the optical semiconductor package cover glass of the present invention, SiO ₂ 50-70% by mass percentage in addition to the _{above, Al 2 O 3 0.1~15%,} B 2 O 3 7~16%, Since it has a basic composition of BaO + SrO + MgO + CaO + Zn 0.5 to 25% and SnO ₂ 0.03 to 1.9%, it has desired optical properties such as light transmittance in addition to high chemical durability. It is also suitable for use in electronic equipment that is used outdoors, such as a highly reliable package window that can transmit accurate optical information to semiconductor elements over a long period of time. It is what you have.

(5) Further, the optical semiconductor package cover glass of the present invention, SiO ₂ fifty-five to sixty-nine% represented by mass% added to the _{above, Al 2 O 2 1.5~15%,} B 2 O 3 7~16%, Since it has a basic composition of MgO 0-5%, CaO 0-10%, BaO 0-12%, SrO 0-10%, CaO + BaO + SrO + ZnO 0.3-13%, SnO ₂ 0.03-1.9%, Glass can be homogenized easily when melted, so that foreign glass with fine dimensions is not mixed, and it is possible to prevent obstructive molding as a window glass for the package. It facilitates the final inspection at the time and brings the trust that can be used with confidence.

  (6) Moreover, since the cover glass for optical semiconductor packages of this invention consists of an alkali free glass in addition to the above, since it does not contain an alkali component substantially, it is various adhesives used when sealing a cover glass. Because it is possible to achieve high confidentiality over a long period of time without degrading the performance of the device, it is applicable to various semiconductor storage packages used in harsh environments than before. This expands the range of use of the semiconductor storage package.

  (7) Furthermore, since the cover glass for optical semiconductor packages according to the present invention contains 0.1 to 15% by mass of an alkali metal element in terms of oxide in addition to the above, high-temperature melting can be easily realized. Even when melting using non-manufacturable manufacturing equipment, it is possible to manufacture cover glass for optical semiconductor packages with a function that can withstand practical use at a low cost, and to support a wide range of elements from high-class devices to popular devices. Is possible.

  (8) Furthermore, since the cover glass for optical semiconductor packages of the present invention has a Ra value of the surface roughness of the light-transmitting surface of 0.5 nm or less in addition to the above, in addition to the high chemical durability of the cover glass, The surface quality is such that fine scratches and cracks are unlikely to occur on the surface, and even thin glass has high strength characteristics, so it can be used for thinning electronic devices such as portable information terminals. It is possible to cope with a reduction in thickness.

(9) Furthermore, since the cover glass for optical semiconductor packages of the present invention has an α-ray emission amount of 0.5 c / cm ² · hr or less in addition to the above, the optical semiconductor element housed in the package is particularly resistant to α-rays. Even if it is poor, it can be used as a cover glass without causing problems such as device malfunction, so it is a package that uses a new optical semiconductor that is highly functional but weak in radiation resistance. It can be used.

  (10) In addition to the above, the cover glass for an optical semiconductor package of the present invention has an alkali elution amount of less than 0.3 mg according to JIS-R3502, an acid resistance of less than 0.2% according to JIS G06, and water resistance. Is less than 0.2%, so it has high performance in terms of acid resistance in addition to water resistance, so even if the portable electronic device is accidentally exposed to acid rain, etc. It is possible to ensure the quality without causing any fundamental trouble, and it is possible to expand the use of the optical semiconductor element storage package and further apply it to electronic devices used outdoors. .

  (11) In addition to the above, the cover glass for an optical semiconductor package of the present invention is used for a package for storing a solid-state imaging device, a package for storing a CMOS, and a package for storing a laser diode. Since the surface properties of the glass brought about by chemical durability that can maintain the performance of high-performance semiconductor elements, it is possible to realize stable electrostatic properties of the cover glass surface. It is a surface property that makes it difficult for foreign matter or the like due to electrification to adhere and easily maintains a clean state immediately after production.

(12) Moreover, the manufacturing method of the cover glass for optical semiconductor packages of this invention mixes a glass raw material, the process of adjusting a glass raw material formulation, The process of throwing this glass raw material formulation in a heat resistant container, , A step of melting a glass raw material preparation into a molten glass in the heat-resistant container, and manufacturing a cover glass for an optical semiconductor package that is processed into a plate-like body having a desired size after the molten glass is formed into a predetermined shape It is a method, The said glass raw material formulation adds Sn oxide as a clarifier, contains 0.02-2.0 mass% of Sn components in conversion of SnO2, and Sn < ₂ ⁺ > / total Sn Therefore, the desired environmental performance, optical properties, mechanical properties, etc. can be obtained without depending on the size of the melting device or the melting glass. Cover glass with Technology that improves the performance of optical functional semiconductors used in information electronic devices such as mobile phones, and technology related to semiconductor products required for higher-performance electronic devices. It is possible to supply a sufficient amount of cover glass to boost the market.

  (13) Moreover, since the manufacturing method of the cover glass for optical semiconductor packages of this invention is characterized by not using an As component, it can improve the safety | security of a glass manufacturing environment in the case of glass manufacture. It will be possible, and will not require toxic management as before.

(14) Moreover, the manufacturing method of the cover glass for optical semiconductor packages of this invention adjusts a glass raw material formulation in the container whose content of any one or more of U, Th, and Ra is 0.01 ppm or less. The amount of α rays emitted from the glass of the plate-like body is reduced to 0 by charging it into a heat-resistant container made of SiO ₂ and / or Pt-containing heat-resistant container while holding the glass raw material composition in the container. .5 c / cm ² · hr or less, the quality of the high purity glass raw material used for the cover glass can be reduced without deteriorating the quality of the glass raw material mixing operation. Since it is possible to continuously mass-produce very few cover glasses, high-quality purity glass can be used without wasting the measures for mixing impurities against other equipment such as glass melting equipment. Stable product Be one that makes it possible to have a small package cover glass with α-ray emission by stable supply to the market, it is made as to encourage further development of the semiconductor industry.

  (15) In addition, since the method for manufacturing a cover glass for optical semiconductor packages according to the present invention is characterized by using an apparatus that employs a molding means that stretches downward, in addition to the various functions described above. Therefore, it is possible to manufacture plate glass with high surface accuracy with a small number of manufacturing processes, and to improve the surface quality of the light-transmitting surface portion of the plate glass that is expected to be accompanied by further increase in the density of optical semiconductor elements in the future. It can be realized reliably.

  The cover glass for optical semiconductor packages and its manufacturing method of the present invention will be described below based on examples.

  About the cover glass of this invention, in order to confirm the performance in clarification, the present inventors investigated by the procedure as shown below. The investigated glass compositions are shown in Table 1. First, weighing was performed using a glass raw material having a purity of reagent quality, which was confirmed by analyzing in advance that impurities and the like can be sufficiently grasped so as to have the glass composition shown in Table 1. Thereafter, mixing was performed for a predetermined time with a small rocking mixer, and a glass raw material mixing batch was prepared in which mixing was sufficiently homogeneous. Next, this glass raw material mixed batch is put into a substantially conical crucible made of platinum-gold, and is installed in an indirect electric resistance furnace maintained at a predetermined temperature, and maintained at 1300 ° C., 2 hours, 1500 ° C., 10 minutes. Then, after vitrification and melting, it was cooled to room temperature in a slow cooling furnace. The glass lump obtained as described above was cut into a thin glass plate having a thickness of 1 mm with a small wire saw. And this thin glass is immersed in the organic solvent which has a refractive index comparable as glass, a binarization process is performed by image analysis under a microscope, and the bubble number below 0.1 mm remain | survives in glass. Measurement was carried out.

The results are shown in Table 1. Sample No. tested 1 to sample no. For No. 12, the number of bubbles was 1.1 to 6.2 pieces / 100 g glass, which was a sufficiently small number of bubbles. On the other hand, as a comparative example, when SnO ₂ added to Sample No. 12 to Sample No. 12 was not added, and melting was performed under the same conditions as described above, the number of bubbles became 150 to 480/100 g glass, and any sample. But it was two orders of magnitude more. From the above facts, it has been found that the tested sample has a foam quality capable of realizing high performance as the cover glass for a semiconductor element storage package window of the present invention.

Further, an indirect electric resistance furnace in which a glass raw material mixed batch prepared by the same procedure as described above so as to have the same glass composition as in Table 1 above was placed in a platinum-rhodium (rhodium 15%) container and maintained at a predetermined temperature. It is placed inside and melted by holding at 1500 ° C. for 3 hours, while stirring with a paddle type stirrer for 1 hour to perform a homogenization operation, then casting on a glassy carbon plate, and in a slow cooling furnace Cooled to room temperature. Using the obtained glass lump, the ratio of Sn ²⁺ / total Sn in the glass, the amount of alkali elution, water resistance, acid resistance, density, and Young's modulus were measured. The obtained results are also shown in Table 1.

As shown in Table 1, sample no. 1 to sample no. No. 12 has a ratio of Sn ² / total Sn in the range of 0.2 to 1.4, and the Sn component is effectively used to clarify fine bubbles present in the glass. It has been found. Also, from Table 1, sample No. From sample 1, sample no. For any of the 12 samples, the alkali elution amount was at most 0.19 mg, the water resistance was 0.02 to 0.11%, and the acid resistance was 0.01 to 0.10%. And was found to have a sufficiently high chemical durability. By the way, in the table, “ND” means that the test has not been performed or is below the detection limit.

Further, for characteristics other than chemical durability, sample No. 1 to sample no. No. 12 has a density of 2.31 to 2.68 g / cm ³ and a specific Young's modulus of 27.3 to 32.4 GPa / g · cm ^−3. As a cover glass for a package window, it has been found to have a property capable of realizing a high function.

  Next, the manufacturing method of the cover glass for optical semiconductor packages of the present invention will be described below. The manufacturing method of the cover glass for the image sensor storage package window, which is a solid-state imaging device, is as follows. First, a plurality of high-purity raw materials are confirmed in advance in a resin-coated container that has been confirmed to have no problem with the U, Th, and Ra contents. Then, the semiconductor element storage package window cover glass of the present invention is precisely weighed so as to have a predetermined composition. The raw materials for which each weighing was completed were confirmed to be covered with high-purity alumina having a total content of U, Th, and Ra of 0.01 ppm or less and maintained in a sufficiently clean state. It is sequentially put into the rocking mixer. Thereafter, a mixing operation is performed by a rocking mixer for 3 hours to perform homogeneous mixing. The mixed batch that has been blended also serves as a raw material charging container, and is stored in a storage container that is coated with high-purity alumina having U, Th, and Ra contents of 0.1 ppm or less. Thereafter, the containers are sequentially installed at the container installation position of the screw charger, the glass mixed raw material is guided to the screw charger, and the glass raw material is supplied into the furnace.

And the glass raw material thrown into the furnace is heated in a SiO ₂ crucible having a capacity of 10 liters heated and held in advance at 1570 ° C. by indirect heating using a SiC heating element, and the vitrification reaction is carried out. Causes it to melt. Thereafter, carbon dioxide bubbles, oxygen bubbles, and the like generated by the decomposition of carbonate and the like are expanded by the action of SnO ₂ added to the glass raw material, and the fine bubbles expand in the molten glass to be clarified. The glass from which bubbles are released in this way has a sufficient degree of homogeneity so that it is sufficiently mixed by a stirrer in which two paddle type stirrers are arranged in series in a mixing tank for homogenization so that there is no striae. Improvement is achieved, and finally it is formed into a thin glass sheet by downdraw molding in a molding tank. The thin glass thus obtained is not only optically homogeneous, but also has a sufficiently small amount of U, Th, Ra, so that the α-ray emission amount is 0.003 to 0.25 c as measured by a gas flow proportional counter. A value of / cm ² · hr was obtained.

  Next, in order to specifically confirm the long-term chemical durability performance of the cover glass for optical semiconductor packages of the present invention, no haze or the like is generated on the light-transmitting surface by HAST (Highly Actressed Stress Test) using a highly accelerated life test apparatus. Or conducted a survey. Table 2 shows the glass compositions evaluated simultaneously as examples and comparative examples of the present invention. For all samples, glass raw materials were mixed in the same manner as described above, and melted at 1500 ° C. for 4 hours in an indirect heating furnace using a platinum-rhodium (rhodium 15%) crucible. After homogenous mixing for 1 hour with a stirrer, the cast block formed by casting was gradually cooled to obtain a glass lump cooled to room temperature. Then, the plate-like body was sliced, and a glass plate was processed as a cover glass using aluminum oxide particles and cerium oxide particles as an abrasive. As a result, a glass plate having both sides mirror-polished to a thickness of 0.7 mm was obtained, and the sample was used for evaluation by HAST. By the way, the surface roughness of the cover glass used in the test is 0.2 to 0.3 nm for the surface roughness of the light-transmitting surface and Ra for each sample by a stylus type measurement using Taly Step manufactured by Taylor-Hobson. It was confirmed that there was. Regarding long-term chemical durability evaluation conditions, the cover glass is kept in a horizontal state under conditions of a temperature of 130 ° C. and a relative humidity of 85%, and left to stand for 100 hours. It was evaluated whether it was recognized. As an evaluation result summarized in Table 2, no abnormality was observed in the sample represented by ◯, and a clouding phenomenon due to surface precipitates or the like was confirmed in the sample represented by X.

As can be seen from Table 2, the sample No. 13-No. No. 16 was a material containing SnO ₂ , but no fogging due to foreign matter precipitation or the like was observed on the surface of the cover glass, and the sample was in a clean state. On the other hand, sample No. evaluated as a comparative example. 17-No. As for No. 20, precipitated foreign matter was observed on the surface, and it was found that there was a problem.

  From the above test results, it becomes clear that the cover glass for an optical semiconductor package of the present invention has high chemical durability and has durability performance even in severe tests such as the HAST test. It was.

In addition, about the ratio of Sn <2 ⁺ > / total Sn in glass, a part of glass lump was used for the chemical analysis, and total Sn and Sn ^{< 2+} > which exist in glass were quantified. For quantification, the glass was decomposed in an acid solution and subjected to instrumental analysis and oxidation-reduction titration. Regarding the Sn ²⁺ content, and the amount of Fe ²⁺ which is generated is reduced by Sn ²⁺ in exploded solution calculated in an indirect way by titration with cerium sulfate solution. Specifically, total Sn was quantified by using an ICP-AES apparatus after thermally decomposing glass powder prepared in advance with sulfuric acid and hydrofluoric acid and dissolving it in hydrochloric acid. Sn ²⁺ is decomposed first in an inert gas atmosphere by adding 2 ml of a 0.1% Fe ³⁺ solution to glass powder, then adding sulfuric acid and hydrofluoric acid and heating in a water bath for 10 minutes. It was. Fe ³⁺ During this warming decomposition operation is reduced with Sn ²⁺ and Fe ²⁺ is produced. Next, boric acid was added thereto to neutralize excess hydrofluoric acid, and then the introduction of inert gas was stopped. Thereafter, 1 ml of 0.015M OsO ₄ solution was added as a catalyst for this reaction, and 1.0 ml of O-phenanthroline indicator was added and then titrated with an N / 200 cerium sulfate solution until the color changed from orange to light blue. Sn ²⁺ was analyzed and quantified.

  Moreover, the alkali elution amount was measured according to Japanese Industrial Standard (JIS-R3502-1995) as described above. Specifically, glass is collected from a part of the glass lump, washed well, dried, then carefully pulverized in an agate or steel mortar, passed through a standard sieve of 420 μm, and over a standard sieve of 250 μm. A powdery glass having a particle size that remains at a value of 1 is obtained. After 5 g of this powdery glass is thoroughly washed with ethyl alcohol to remove fine powder, it is dried in an air bath at about 125 ° C. for 30 minutes. And after cooling this powdery glass in a desiccator, the same gram number as the specific gravity of sample glass is accurately measured from the obtained powdery glass. On the other hand, after putting 40 cc of distilled water in a round bottom flask in advance and holding it in a boiling water bath for 10 minutes, a sample weighed in the flask was added, and another sample adhered to the inner surface of the container with 10 cc of distilled water. Wash off the part. While slowly rocking in this state, the upper part of the sample is stabilized to be a uniform plane. A condenser is then attached to the top of the flask and heated in a boiling water bath for 60 minutes. Then, the flask is taken out of the water bath, immediately cooled with running water, the content liquid is transferred to a beaker made of hard glass, 3 drops of methyl red indicator are dropped and titrated with N / 100 sulfuric acid. On the other hand, a blank test is performed in the same test procedure, and the results are compared. The result thus obtained is calculated by subtracting the result of the blank test, and finally the result as the alkali elution amount is obtained.

  As for water resistance and acid resistance, the weight loss rate under each condition was measured in accordance with the regulations of the Optical Glass Industry Association Standard (JOGIS06) as described above. Further, the density was measured by the well-known Archimedes method. The specific Young's modulus is a value calculated from Young's modulus and density measured by a bending resonance method using a non-destructive elastic modulus measuring device (KI-11) manufactured by Kanebo Co., Ltd.

  Based on the results of the series of investigations described above, the glass composition shown in Table 3 was melted using a melting facility provided with a heat-resistant container made of larger platinum-rhodium 15%, and finally A plate glass was formed by adopting a forming method using molten glass overflowed from the refractory soot as a downward stretch forming method as a forming method. And it investigated whether the plate glass shape | molded by this shaping | molding method can implement | achieve the surface quality which becomes fully practical.

As a result, no. 21 to No. For samples up to 25, the surface roughness was 0.08 to 0.32 nm, and it was found that the surface roughness was 0.5 nm or less. In addition, other bubble numbers, density, specific Young's modulus, Sn ²⁺ / total Sn ratio, etc. are not affected by the same measurement method as described above, and are characteristic as the cover glass for optical semiconductor packages of the present invention. We were able to confirm that we have both.

Claims (18)

In the cover glass for optical semiconductor packages made of inorganic oxide glass,
Optical semiconductor package cover glass, characterized in that it contains 0.02 to 2.0 wt% of Sn component in terms of SnO _2. The ratio of Sn ²⁺ / total Sn in the glass is 0.15 or more, the Si component is contained in an amount of 50 to 70% by mass in terms of SiO ₂ , and the Al component is in an amount of 0.1% by mass or more in terms of Al ₂ O ₃ The cover glass for optical semiconductor packages according to claim 1, which is contained. The B component contains 5 to 20 wt% in terms _of B ₂ O _3, and wherein the Al component in claim 1 or claim 2, characterized in that it contains 0.1 to 19 wt% in terms of Al ₂ O ₃ Cover glass for optical semiconductor packages. SiO ₂ 50-70% by mass _{percentage, Al 2 O 3 0.1~15%,} B 2 O 3 7~16%, BaO + SrO + MgO + CaO + ZnO 0.5~25%, of SnO ₂ 0.03 to 1.9% The cover glass for optical semiconductor packages according to any one of claims 1 to 3, which has a composition. SiO ₂ 55-69%, Al ₂ O ₃ 1.5-15%, B ₂ O ₃ 7-16%, MgO 0-5%, CaO 0-10%, BaO 0-12%, SrO 5. The cover glass for an optical semiconductor package according to claim 1, having a composition of 0 to 10%, CaO + BaO + SrO + ZnO 0.3 to 13%, SnO ₂ 0.03 to 1.9%.   The cover glass for optical semiconductor packages according to any one of claims 1 to 5, wherein the cover glass is made of alkali-free glass.   The cover glass for an optical semiconductor package according to any one of claims 1 to 5, comprising an alkali metal element in an amount of 0.1 to 15% by mass in terms of oxide.   8. The cover glass for an optical semiconductor package according to claim 1, wherein the surface roughness of the light transmitting surface is 0.5 nm or less in terms of Ra value. The cover glass for an optical semiconductor package according to any one of claims 1 to 8, wherein the α-ray emission amount is 0.5 c / cm ² · hr or less.   The alkali elution amount specified in JIS-R3502 is less than 0.3 mg, the acid resistance specified in JOGIS06 is less than 0.2%, and the water resistance is less than 0.2%. The cover glass for optical semiconductor packages according to any one of 9. 11. The cover glass for an optical semiconductor package according to claim 1, wherein the density is 2.7 g / cm ³ or less and the specific Young's modulus is 27 GPa / g · cm ⁻³ or more.   The optical semiconductor package cover glass according to claim 1, wherein the optical semiconductor is a solid-state imaging device.   The optical semiconductor package cover glass according to claim 1, wherein the optical semiconductor is a CMOS.   The optical semiconductor package cover glass according to any one of claims 1 to 11, wherein the optical semiconductor is a laser diode. A step of mixing a glass raw material to prepare a glass raw material preparation, a step of introducing the glass raw material preparation into a heat-resistant container, and a melting step of the glass raw material preparation into the molten glass in the heat-resistant container A process and a method for producing a cover glass for an optical semiconductor package, wherein the molten glass is formed into a predetermined shape and then processed into a plate-like body having a desired dimension,
The glass raw material preparation is obtained by adding Sn oxide as a fining agent, containing 0.02 to 2.0% by mass of Sn component in terms of SnO ₂ , and the ratio of Sn ²⁺ / total Sn is 0.00. A method for producing a cover glass for an optical semiconductor package, comprising obtaining a plate-like glass of 15 or more.   The method for producing a cover glass for an optical semiconductor package according to claim 15, wherein an As component is not used as a fining agent. While mixing a glass raw material in a container having a content of one or more of U, Th, and Ra of 0.01 ppm or less to adjust the glass raw material preparation, while holding the glass raw material preparation in the container The amount of alpha rays emitted from the glass of the plate-like body is reduced to 0.5 c / cm ² · hr or less by being poured into a heat-resistant container made of SiO ₂ and / or a Pt-containing heat-resistant container and melted. A method for producing a cover glass for an optical semiconductor package according to any one of claims 15 to 16.   18. The method for producing a cover glass for an optical semiconductor package according to claim 15, wherein an apparatus that employs a molding means that stretches downward is used.