JPS6077144A - Ultraviolet light transmitting glass - Google Patents

Abstract

PURPOSE:The titled glass, containing specific composition amounts of SiO2, B2O3, Na2O and Al2O3, obtained by replacing oxygen ions partially with fluorine ions, fusible to alumina packages for semiconductors, meltable at relatively low temperatures, and having a low viscosity. CONSTITUTION:An ultraviolet light transmitting borosilicate glass, containing 56-70wt%, preferably 63-68wt% SiO2, 16-35wt%, preferably 20-25wt% B2O3, 4.7-13.0wt%, preferably 5-11wt% Na2O, 3-7wt% Al2O3, <0.55 ratio (Na2O/B2O3), >=95wt%, preferably >=97wt% SiO2+B2O3+Na2O+Al2O3, obtained by replacing oxygen ions with fluorine ions to contain 2.5-10wt% fluorine in the above-mentioned composition, having a high transmittance particularly of light at about 253nm wavelength, and meltable at <= about 1,500 deg.C temperature. The above-mentioned glass can be produced at a low cost by adding 0.2-1.5wt% reducing agent to a compounding raw material to make the raw material containing much impurities, e.g. iron, usable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to borosilicate glass that has excellent ultraviolet transmission performance and can be melted into alumina packages for semiconductors at temperatures below 1,500 tons, and is particularly used in computers. The present invention relates to a glass for an ultraviolet-transmitting window of an ultraviolet-erasable ROM (UV-type EPROM), which is a type of semiconductor memory.

The glass used as the window glass for UV-type IPROM is required to have the following properties: high transmittance for light with a wavelength of 253 nm, ability to be fused to an aluminum nano arm cage, and ease of mass production.

Due to these requirements, S10. Borosilicate glass, which has a high N82°'BtOs ratio and a low ratio, was used. This type of glass has extremely high viscosity when melted, making it difficult to defoam, and it is difficult to remove bubbles when melted. However, it has been difficult to obtain homogeneous glass without bubbles.

The present invention is based on sto, 'yo weight% or less, Na2O34,7
By adding an appropriate amount of fluorine to borosilicate salt glass containing more than % by weight! The transmittance at a wavelength of lls253 nm is improved and the viscosity of the glass is reduced. The reason why the transmittance at the wavelength of 5.253 nm increases and the viscosity decreases by adding fluorine is BO.
This is because some of the oxygen ions in the 4 groups are replaced by fluorine ions, a part of the glass network is cut by the fluorine ions, and the fluorine ions bond to the terminals, so that single-bonded oxygen is not generated. Conceivable. By adding a reducing agent, raw materials with many impurities such as iron can be used due to its reducing effect, and raw material costs can be reduced. That is, according to the present invention, it can be sufficiently melted at a temperature of i.
A glass having a transmittance of 80% or more can be obtained.

The composition range of the present invention is sio in weight percentage, 56-70%, preferably 63-68% B2
O3 16-35%, preferably 20-25% Nano
47. ~13%, preferably 5-11%kl*os”
~7% Na20/B, O, <0.55 8 i 0. +B20n 10N a, O+A 12
0s≧95%.

Preferably, it is 297%, and oxygen ions are replaced with fluorine ions so that 2.5 to 10% by weight of fluorine is included in the above composition.

To explain the reason for limiting the composition range of the present invention, 8102 is 7
If it is more than 0%, a melting temperature of 1,500 C or more is required, which is contrary to the purpose of the present invention, and if it is less than 56%, the chemical durability is poor and it is not practical. B! When 03 is less than 16%, the melting temperature is high and it is unsuitable, and when it is more than 35%, it has poor chemical durability. ) If Ja40 is 4.7% or less, it requires a dissolution humidity of 1,500C or more, which is contrary to the purpose of the present invention.
If it is 1% or more, the transmittance at a wavelength of 253 nm becomes poor. It is also possible to replace a part of Na2O with Li, 0, and O, but 1, 1.0 increases the phase separation tendency of this glass, and K and O tend to decrease the transmittance in the ultraviolet region. Therefore, these components account for 3% of the total alkali metal oxides.
It is desirable that it is 0% or less. A J, ox completely suppresses the phase separation of this type of glass and improves the chemical durability, so it is necessary to have an amount of 3% or more, but if it is more than 7%, the glass becomes highly viscous υ, and it is not suitable for the purpose of the present invention. do not have. Although a small amount of MgO, CaO, etc. can be introduced to promote glass melting, it reduces the transmittance in the ultraviolet region, so 810
, , Nano, Am, 01 and B20. The total amount of other components is 5% or less, preferably 3% or less.

In order to improve the transmittance in the ultraviolet region, 2.5% or more of fluorine is required, but if it exceeds 10%, the fluorine content will be too strong and a homogeneous glass will not be obtained. .5 to 10% is appropriate. In order to eliminate absorption in the ultraviolet region by iron ions contained in trace amounts in the glass raw materials or mixed in during the glass manufacturing process, all of the reducing agent is added to the blended raw materials to reduce the amount of Fe in the glass to "f Fe". It is effective to do so. Effective reducing agents include organic compounds such as marten powder and mannitol, and metallic silicon. Appropriate amount of reducing agent Melts Mi
When melting using :, the content is 1.5% or less in the case of ten flour and 0.1% or less in the case of metallic silicon. If the amount added is too large, carbon and metallic silicon will remain and the glass will be colored, which is not preferable.

Next, examples of the present invention will be described.

(tvt%) T113 (%) ' Transmittance at wavelength of 2s 3Hm, sample 1m thickness F + NaF, AJF, calculated from fluorine content award. Alumina, sodium carbonate, aluminum fluoride or sodium fluoride were blended as raw materials, and 0.5 to 1.0% of starch was added as a reducing agent to the blended raw materials as required. All of this blended raw material is placed in a melting pot and melted at 1400 to 1500C in an electric furnace.
After degassing while stirring, the mixture was poured into a mold and slowly cooled at room temperature. All samples were taken from a part of this glass and the thickness was 1ffl.
#1 and the transmittance at 253 nm was measured using a total spectrophotometer. The results are also shown in the table together with the transition temperature Ty and thermal expansion coefficient α of these glasses.

In FIG. 1, the thickness is j==1. The spectral transmittance curve in the case of Q13m is shown. Figure 2 shows 810.59.5 wt%
-B, 03 28.5- Na, 07.2- AJ20
．． Glass with a composition of 4.8 and iF using this as a pace,
The spectral transmittance curves of glass having a composition (No. 2 in the table) in which 105.4 wt% of fluorine was added using g'i were shown. None of them contain reducing agents. The increase in transmittance in the ultraviolet region due to the inclusion of fluorine is remarkable.

As described above, according to the present invention, conventional borosilicate glass for transmitting ultraviolet rays can be melted at a low temperature, and a 25.3 nm
A glass with high transmittance can be obtained.

This glass is homogeneous with few bubbles, so it is suitable for EPROM
Suitable as ultraviolet transmitting glass.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the spectral transmittance curve of one example of the ultraviolet transmitting glass of the present invention, and FIG. 2 is a diagram showing the difference in the transmittance curves of the glass containing fluorine and that containing no fluorine. Fukaya Glass Co., Ltd. Agent Masayuki Asakura

Claims (1)

[Claims] 1. 810 in overlapping percentage, 56-70% B, 0, 16-35% Na, 0 4.7-13.0% Al, 033-7% NatOs/BtQa (0, 55 8i 02+B2O3+Na, O+AJ10g 2 9
5% and that oxygen ions are replaced with fluorine ions so that the above composition contains seven types of 2.5 to 10% by weight. 2. S10. in weight percentage. 63-68% Btos 20-25% Na, 05-11% A J, 0. 3-7% Na, O/B, 08 (0,55 810H+B10B +Na, O+A To Os
2. The ultraviolet transmitting glass according to claim 1, wherein the composition contains 2.5 to 10% by weight of fluorine by replacing oxygen ions with fluorine ions. 3. The ultraviolet transmitting glass according to claim 1 or 2, wherein 0.2 to 1.5 weight percent of a reducing agent is added to the raw materials.