JP3283722B2 - Window glass for semiconductor package and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a window material glass for a semiconductor package and a method of manufacturing the same, and more particularly, to a glass material used as a window material for a semiconductor package such as a CCD (solid-state imaging device) used for a video camera or the like. And its manufacturing method.

[0002]

2. Description of the Related Art A semiconductor such as a CCD causes a soft error due to α rays emitted from a window material for a package.
Reduction of the amount of radioisotopes that emit α rays contained in window materials for packages has been performed. The radioisotope typically includes uranium (U), thorium (Th) and radium (Ra), but Ra is not usually a problem because of its small amount, and U and Th are problems. ing. In particular, U emits a large amount of α-rays, and is 5-1 to 1 compared with Th.
About 0 times more. Therefore, in order to reduce the amount of α-ray emission in the semiconductor peripheral material, it is particularly important to reduce the U content.

For this reason, several proposals have already been made for the purpose of reducing the α dose irradiated to the solid-state imaging device. For example, Japanese Patent Application Laid-Open No. 3-74874 proposes a solid-state imaging device characterized in that a silicate glass thin film containing lead is formed on a sensor portion to block radiation. However, in the manufacture of this solid-state imaging device, the process of forming the silicate glass thin film is complicated, and requires a long time and is expensive.

On the other hand, JP-A-5-275074 discloses that the content of radioisotopes is 100 ppb or less and the amount of emitted α-rays is 0.05 c / cm ² · hr or less, making it difficult to purify and separate α-ray radioactive elements. Fe ₂ O ₃ , TiO ₂ , Pb
Glasses free of O and ZrO ₂ have been proposed, and examples include α-ray emission of 0.08 to 0.005 c / cm ^2.
hr glass is disclosed. Also, Japanese Patent Laid-Open No.
No. 539 discloses that ZrO ₂ containing a large amount of U and Th,
A low-radiation glass that does not contain BaO and does not contain K ₂ O that causes β-ray generation has been proposed. Examples of the glass have an α-ray emission of 0.008 to 0.002 c / cm ² · hr. Is disclosed.

[0005]

However, in recent years,
With the increase in the density of solid-state imaging devices, noise and soft errors due to α-rays have become obstacles to improving image quality. Therefore, the demand for reducing the amount of emitted α-rays has become more severe, and recently, the demand for 0.0015 c / cm ² · h
The target has been reached below r. However, in order to achieve this goal, the content of U, which has a large amount of α-ray emission, is 5%.
Glasses above ppb were virtually impossible.

Incidentally, the window glass for a semiconductor package is required to be a material that does not generate cracks or distortion when sealed with an alumina ceramic package. As shown in FIG. 1, the optical system of the color VTR camera is composed of a lens system 1 for forming an image, a quartz plate 2, 3 acting as a low-pass filter, and a near-infrared absorption filter 4 having a sensitivity correcting function. Device 5 and solid-state imaging device 6
It is composed of In the solid-state imaging device 6, a CCD chip 7 having a three-color mosaic filter formed on its light-receiving surface is set in an alumina package 8, and a glass window material 9 serving as a light transmitting member for protection is adhered thereon with an epoxy resin or the like. Configuration. Therefore, it is necessary to match the thermal expansion coefficients of the glass package window material 9 and the alumina ceramic package 8. The coefficient of thermal expansion of alumina ceramic is usually in the range of 60 to 75 × 10 ⁻⁷ K ⁻¹ , and the coefficient of thermal expansion of glass is the same or slightly smaller, in the range of 45 to 75 × 10 ⁻⁷ K ⁻¹ . Desirably. The sensitivity range of the CCD extends from the visible light region to the near infrared light region. Therefore, it is necessary to use a near-infrared absorption filter to cut off the near-infrared portion of the incident light, make the overall sensitivity approximate to visibility, and improve color reproducibility, as shown in FIG. As described above, in the element 5, the near-infrared absorption filter 4 is incorporated between the three quartz plates 2 and one quartz plate 3, so that the number of layers constituting the element 5 is large and the manufacturing cost is high. There were drawbacks.

Accordingly, an object of the present invention is to (i) reduce the contents of U and Th, suppress the occurrence of soft errors in a solid-state imaging device, and contribute to the improvement of image quality. (Ii) Alumina package and thermal expansion coefficient Has the advantage of being excellent in the sealing property with the alumina package, and, if necessary, has (iii) a sensitivity correction function as well.
It is an object of the present invention to provide a window glass for a semiconductor package having advantages such as cost reduction and a method for manufacturing the same.

[0008]

[SUMMARY OF Hitherto, radioactive isotopes contained in the glass, due to the raw material of the glass was believed to be almost. However, the present inventor
As a raw material for the glass, a glass was trial-produced using a high-purity glass having a very low content of radioisotope, and it was found that the radioisotope content of the obtained glass was still at a high level. That is, in order to reduce the radioisotope contained in the glass, it was found that it is necessary to suppress the contamination in the glass manufacturing process in addition to carefully selecting the raw material of the glass. As a specific means for preventing the mixing of radioisotopes during the glass production process, the glass is obtained by melting the glass in a state where all or a part of the surface of the molten glass is kept out of contact with the atmosphere in the melting furnace. The glass obtained has a U content of less than 5 ppb and a Th content of less than 5 ppb, so that the alpha emission is 0.0015 c / c
m ² · hr or less, and found to be suitable as window glass for semiconductor packages. Further, it has been found that it is preferable to use a specific borosilicate glass or a specific near-infrared absorbing glass as the glass material.

[0009] The present invention has been completed based on this finding, the present invention is the Weight%, the P ₂ O ₅ 50
８５85% and Al ₂ O ₃ ４4-20%, the total of both is 63% or more, CuO 、 0.1０．１10%, no alkali metal oxide, and thermal expansion coefficient 4
5~78 × 10 ^-7 K consists infrared absorbing glass is ^-1, U window material glass and semiconductor package, wherein the content of and Th are both 5ppb or less semi
Solid-state imaging device with window glass for conductor package
Is the gist.

[0010] The semiconductor package window material Glass semiconductor package window material glass is first present invention will be described.

In the window glass for a semiconductor package of the present invention, both the contents of U and Th are 5 ppb or less. As a conventional window glass for a semiconductor package, only a glass having a U content of more than 5 ppb has been obtained, and in this respect, the window glass for a semiconductor package of the present invention is a novel glass which has not existed conventionally. Such a window glass for a semiconductor package according to the present invention, in which both the contents of U and Th are extremely low at 5 ppb or less, has an extremely low U and Th content, and as a result, has an α-ray emission of 0.0015 c / cm.
^It is extremely low at ² · hr or less, and when used in a solid-state imaging device, the soft error rate can be significantly reduced.

In the window glass for a semiconductor package of the present invention, the contents of U and Th are both preferably 3 ppb or less, and the amount of α-ray emission is preferably 0.001 c / cm ² · hr or less.

As a material of the window glass for a semiconductor package of the present invention, a near-infrared absorbing glass containing borosilicate glass or CuO and based on P ₂ O ₅ —Al ₂ O ₃ can be mentioned.

The borosilicate glass, which is one embodiment of the glass material of the present invention, preferably contains 50% by weight of SiO ₂ .
To 78% B ₂ O ₃ 5 to 25% of Al ₂ O ₃ 0 to 8%
Li ₂ O 0-5% of Na ₂ O 0 to 18% and K ₂ O 0-20% (however, the _{Li 2 O + Na 2 O +} K 2 O 5~2
0%), the content of the above components is at least 80% or more, and the thermal expansion coefficient is preferably 45 to 75 × 10 ⁻⁷ K ⁻¹ .

The operation of each component in the borosilicate glass and the reason for limiting the composition will be described below.

SiO ₂ and B ₂ O ₃ are components that form the skeleton of borosilicate glass. SiO ₂ is less than 50% and B ₂
If O ₃ exceeds 25%, the weather resistance tends to decrease.
If the content of SiO ₂ exceeds 78% and the content of B ₂ O ₃ is less than 5%, the meltability tends to deteriorate. Therefore, SiO ₂ is 50
In the range of to 78%, and B ₂ O ₃ is suitably in the range of 5-25%.

Al ₂ O ₃ is a component for improving the weather resistance of glass. However, if it exceeds 8%, striae tend to be easily generated in the glass. Therefore, the content of Al ₂ O ₃ is suitably set to 8% or less.

Li ₂ O, Na ₂ O and K ₂ O are components that act as fluxes and improve devitrification resistance. For that purpose, the total content of one or more of these components is suitably 5% or more. However, one of these components
If the total content of the species or two or more species exceeds 20%, the weather resistance tends to deteriorate and the coefficient of thermal expansion tends to be too large. Further, among these components, Li ₂ O, when added in a large amount, tends to deteriorate the devitrification resistance and has a strong effect of eroding a refractory container. Therefore, the content of Li ₂ O is preferably set to 5% or less. Na ₂ O and K ₂
If O exceeds 18% and 20%, respectively, the weather resistance tends to deteriorate and the coefficient of thermal expansion tends to be too large.
Therefore, the contents of Na ₂ O and K ₂ O are 18
% And 20% or less.

In addition to the above components, alkaline earth metal oxides (MgO, CaO) may be used within a range of 20% or less for the purpose of improving weather resistance, melting property and devitrification resistance, and adjusting the coefficient of thermal expansion. ,
It is also possible to add halogens such as (SrO, BaO), ZnO, and Cl. Further, a defoaming agent such as As ₂ O ₃ or Sb ₂ O ₃ can be appropriately added as needed. or,
Other trivalent or higher valent metal oxides can be added to such an extent that desired properties are not impaired.

Another embodiment of the glass material according to the invention, the near-infrared absorbing glass containing CuO and based on P ₂ O ₅ —Al ₂ O ₃ , is preferably P ₂ O ₅ 5
It contains 0 to 85% and 4 to 20% of Al ₂ O ₃ , the total of both is 63% or more, contains 0.1 to 10% of CuO, and has a thermal expansion coefficient of 45 to 75 × 10 ^−7. Those which are K ^-1 are preferred. The CuO content, the use of P ₂ O ₅ -Al ₂ O ₃ based near-infrared absorbing glass as window material glass for semiconductor packages, can serve also as a function of the near infrared absorption filter. That is, as shown in FIG. 2, by using a near-infrared absorbing glass 11 in which the thermal expansion coefficient of the alumina ceramic package 8 is matched with the thermal expansion coefficient as the window glass for the package, as shown in FIG. There is no need to provide the external absorption filter 4 between the quartz plate 2 and the quartz plate 3, which makes it possible to reduce the size and cost of the product.

The function of each component of the near-infrared absorbing glass and the reason for limiting the composition will be described below.

P ₂ O ₅ has a high visible light transmittance, a good cut-off property for near-infrared light, and is an essential component for obtaining a glass suitable for sensitivity correction. However, if it exceeds 85%, the viscosity of the glass tends to be too high, and the volatilization becomes severe, making the melting difficult. Therefore, the upper limit is 85%.
Preferably it is 80%. On the other hand, if P ₂ O ₅ is less than 50%, the coefficient of thermal expansion tends to be too large, so the lower limit is 50%, preferably 55%.

Al ₂ O ₃ is a particularly effective component for improving chemical durability. However, if it is less than 4%, the effect is not sufficient, and if it exceeds 20%, the devitrification resistance tends to deteriorate. Therefore, the lower limit is 4%, preferably 7%, and the upper limit is 20%, preferably 15%.

The content of CuO is 0.1 to 10%, preferably 0.1 to 6%. CuO is effective in cutting near-infrared light, but less than 0.1% is less effective.
If it exceeds 0%, the transmittance of visible light tends to deteriorate together with the devitrification resistance.

Further, the content of B ₂ O ₃ is 0 to 15%, the content of SiO ₂ is 0 to 25%, and MgO, C
aO-, SrO, is one or more of the content of the group consisting of BaO and ZnO is _{0~25%, B 2 O 3,} SiO
₂ , the content of one or more of the group consisting of MgO, CaO, SrO, BaO and ZnO is 5 to 37%;
And P ₂ O ₅ , Al ₂ O ₃ , B ₂ O ₃ , SiO ₂ , MgO,
The total content of the group consisting of CaO, SrO, BaO and ZnO is preferably at least 85%.

SiO ₂ and B ₂ O ₃ are effective for improving the devitrification resistance and reducing the coefficient of thermal expansion. However, SiO ₂
Becomes the flame熔性exceeds 25%, B ₂ O ₃ tends to deteriorate resistance to devitrification when it exceeds 15%.

MgO, CaO, SrO, BaO and Zn
O is effective for improving the melting property and the devitrification resistance. However, if it exceeds 25%, the coefficient of thermal expansion becomes too large, and it becomes difficult to obtain a desired coefficient of thermal expansion.

Further, B ₂ O ₃ , SiO ₂ , MgO, Ca
The total amount of the group consisting of O, SrO, BaO and ZnO is in the range of 5 to 37%, preferably 6 to 30%, from the viewpoints of meltability, devitrification resistance, coefficient of thermal expansion and transmission characteristics. Appropriate.

Further, P ₂ O ₅ , Al ₂ O ₃ , B ₂ O ₃ , SiO
_2. The total content of the group consisting of MgO, CaO, SrO, BaO and ZnO is suitably at least 85%, preferably at least 90%, for the same reason. In addition to the above components, for the purpose of improving weather resistance, melting property, devitrification resistance, etc., adjusting the coefficient of thermal expansion, etc., within 15%, preferably 1%.
Sb ₂ O ₃ , Nb ₂ O ₅ , PbO, La within the range of 0%
It is also possible to contain ₂ O ₃ , an alkali metal oxide and the like.

The raw materials for forming the above borosilicate glass and CuO-containing, P ₂ O ₅ —Al ₂ O ₃ base glass may be in any form such as an aqueous solution, a carbonate, a nitrate, a hydroxide and an oxide. . However, as described above, it is necessary to select a raw material having a low content of U and Th mixed as impurities. The present invention relates to the semiconductor package described above.
Solid-state image sensor with window glass
However, other configurations of the solid-state imaging device are
It is the same as

Method for Producing Window Material Glass for Semiconductor Package The method for producing window material glass for a semiconductor package according to the present invention comprises:
The method is characterized in that the glass is melted in a state where all or part of the surface of the molten glass is kept out of contact with the atmosphere in the melting furnace.

As a method for preventing all or a part of the surface of the molten glass from coming into contact with the atmosphere in the melting furnace, there are the following methods: (a) All or part of the surface of the molten glass in the melting furnace is cut off with a blocking gas. (B) a method of covering all or a part of the surface of the molten glass in the melting furnace with a lid made of platinum and / or a ceramic having a small content of radioisotope, (c) contacting the atmosphere in the melting furnace. Platinum and / or inner wall
Alternatively, there is a method using a melting furnace made of ceramics having a small content of radioisotope . The reason why the glass having very low U and Th contents can be obtained by employing the above method (a), (b) or (c) is presumed as follows. That is, in the melting operation of glass, a radioisotope, particularly U vapor is generated from a brick or a heating element (for example, a silicon carbide sintered body or a molybdenum silicide sintered body) constituting the inner wall of the melting furnace. By blocking at least one of a) to (c) from contacting all or a part of the glass surface with the atmosphere in the melting furnace, U vapor is prevented from being mixed into the glass.

The method of the present invention comprises the above methods (a) and (b)
The method (c) may be carried out by employing any one of the methods (a) and (c), and the method (a) or the method (b) may be used in combination with the method (c).

As the blocking gas used in the above method (a), it is possible to prevent the glass from coming into contact with the atmosphere of the melting furnace,
Any type is possible as long as it is substantially inert to the glass. For example, hydrocarbon gases such as N ₂ , Ar, air, carbon dioxide, CH ₄ , and LNG can be used.

The melting furnace used in the above method (c) comprises:
It is preferable to use a muffle furnace in which the inner wall is made of a ceramic having a small content of radioisotope, but the muffle structure does not necessarily have to be used.
The effect can be obtained even if the side walls and the like are made of a ceramic having a small radioisotope content. These ceramics include U
Alumina electroformed bricks and silica blocks having a content of 20 ppm or less, preferably 1 ppm or less are suitable.
Further, it is desirable to suppress the use of a resistance heating element such as a silicon carbide sintered body or a molybdenum silicide sintered body, and to heat a gas such as LNG.

In the method for manufacturing a window glass for a semiconductor package according to the present invention, the amount of Th can be further reduced by removing the surface layer on the end surface other than the opposing polished surface. This point is described in detail below. That is, when polishing the glass to the package window material, usually, the ends of the non-polishing surface opposite to it is a cut surface or rough shear surface, the CeO ₂ abrasive on the cut surface or rough shear surface By sticking and remaining without being washed, ThO ₂ which is an impurity in CeO ₂ becomes an α-ray source.
Therefore, by fixing the uneven portion at the end portion in advance by acid treatment or the like, it is possible to prevent CeO ₂ from sticking during polishing. After polishing, the end surface layer may be removed by an acid treatment or the like.

The characteristic requirements of the method for manufacturing a window glass for a semiconductor package according to the present invention have been described above.
In order to obtain a glass having both U and Th contents of 5 ppb or less, a prerequisite is to use a high-purity raw material having the lowest possible radioisotope content, and to minimize the radioisotope in the preparation of the raw material and transfer to the melting furnace. Of course, care must be taken to avoid mixing. The present invention
Semiconductor package obtained by the method detailed above
Related to a solid-state imaging device equipped with window glass for windows
However, other configurations of the solid-state image sensor are conventional
Is the same as

[0038]

The present invention will be described in more detail with reference to the following examples.

(Example 1) Using various high-purity raw materials,
No. 1 in Table 1. A raw material batch was prepared to have a composition of 1. The amounts of U and Th contained in this raw material batch were 0.8 ppb and 3.2 ppb, respectively, calculated from the amounts of impurities of U and Th contained in each raw material. This raw material batch (10 kg in terms of oxide) is put into a 5 liter platinum crucible, and N ₂ gas is flown in a Kanthal super furnace (using a molybdenum silicide heating element) at a flow rate of 40 liter /
Then, the glass material was melted and purified (defoamed, homogenized) at 1480 ° C. for 8 hours while shutting off the glass material from the atmosphere of the melting furnace. A glass block (hereinafter referred to as glass A) was obtained by casting into an iron metal frame and performing predetermined annealing. The U and Th contents of this glass A were determined using the Yokogawa Electric Corporation's TCP-M
As a result of analysis using ASS, 2.5 ppb
And 3.4 ppb, and the U and Th contents are both 5 ppb.
pb or less.

Comparative Example 1 A glass block (hereinafter referred to as comparative glass V) was obtained in the same manner as in Example 1 except that N ₂ gas was not introduced. This comparative glass V
Have a U and Th content of 42 ppb and 3.6 p, respectively.
pb, and the U content was significantly higher than that of Example 1.

From the results of Example 1 and Comparative Example 1, it was found that the U content can be significantly reduced by replacing the atmosphere in the furnace with N ₂ gas and isolating the glass from the atmosphere in the furnace.

(Example 2) A raw material batch was prepared using a high-purity raw material so as to have a composition of 4. The amount of U and Th contained in this raw material batch was calculated from the amount of impurities of U and Th contained in each raw material.
ppb and 0.1 ppb. As shown in FIG. 3 for heating and melting the glass, it is composed of an outer wall material 12 and a silicon carbide heating element 13, and an inner wall 14 is partitioned by a silica block.
An electric furnace 15 having a muffle structure was used. The U and Th contents of the inner wall 14 (silica block) and the outer wall material 12 (chamotte brick) of the electric furnace are U: 19 ppb, respectively.
Th: 0.1 ppb and U: 30 ppm, Th: 55 p
pm. 1 batch of raw material (2 kg in oxide)
Using a platinum crucible having a liter capacity, the mixture was melted and purified at 1430 ° C. for 6 hours, cast into an iron metal frame, and annealed in a predetermined manner to obtain a glass block (hereinafter referred to as glass B).
When this glass B was analyzed, the contents of U and Th were 1.2 ppb and 0.2 ppb, respectively.

Comparative Example 2 A glass block (hereinafter referred to as Comparative Glass W) was prepared under the same conditions as in Example 2 except that an electric furnace was used in which the inner wall of the silica block 14 in FIG. 3 was removed.
). The analysis values of U and Th of the comparative glass W were 18 ppb and 0.3 ppb, respectively.

From the results of Example 2 and Comparative Example 2, it was found that the portion in contact with the furnace atmosphere was made of a material having a low content of radioisotopes, and the glass was cut off from the furnace atmosphere. It has been found that the content can be reduced.

(Example 3) Glass A obtained in Example 1
Is polished by an ordinary method to obtain a predetermined shape (15.5 × 1
7.7 × 0.8 mm) package window glass (hereinafter referred to as glass C) was produced. 15.5 of this glass C
The × 17.7 mm surface is a polished surface, but 15.5 ×
The 0.8 mm plane and the 17.7 × 0.8 mm plane are chamfered cut surfaces. A protective film was applied to the polished surface, immersed in a hydrofluoric acid aqueous solution, and only the end face was etched. Then, the protective film was removed to obtain glass (hereinafter referred to as glass D). The U and Th analysis values of glass C before etching are U:
2.5 ppb, Th: 5.8 ppb, and the U and Th analysis values of the glass D after etching are U: 2.3 p, respectively.
pb, Th: 3.8 ppb. That is, it has been found that the removal of the rough surface at the end can reduce the Th of the polished product.

(Embodiment 4) A raw material batch was prepared using various high-purity raw materials so as to obtain a composition of 1. The amounts of U and Th contained in this raw material batch were 0.7 ppb and 0.4 ppb, respectively, calculated from the amounts of U and Th impurities contained in each raw material. This raw material batch (12 kg in terms of oxide) was supplied to the muffle furnace shown in FIG.
Using a 1-liter silica crucible, the mixture was roughly melted at 1350 ° C. for 3 hours, transferred to a 5-liter platinum crucible, further melted at 1350 ° C. for 5 hours, and purified. A glass block was obtained by casting into an iron metal frame and performing predetermined annealing. After polishing this glass by a conventional method, the end face was removed in the same manner as in Example 3 to obtain 15.5 × 17.7 ×
A 2.0 mm window glass for a package (hereinafter referred to as glass E) was obtained. The analysis values of U and Th of this glass E were 1.9 ppb and 0.8 ppb, respectively. The spectral transmittance of the glass E is, as shown in FIG.
It had a near-infrared light cutoff characteristic suitable for sensitivity correction.

(Test Example) As a window material glass for a package, a polished plate obtained by polishing glass A or B by a conventional method and glass C, D or E itself are used, and these have an effective pixel number of 580,000 pixels. CCD
The chip was sealed in an alumina ceramic package having a built-in chip using an epoxy resin-based adhesive to produce a solid-state imaging device.

For comparison, a commercially available package window glass (hereinafter referred to as Comparative Glass X) was used as the package window glass.
) Was similarly polished to obtain a solid-state imaging device.

An attempt was made to manufacture a solid-state image sensor using a commercially available near-infrared absorbing glass for sensitivity correction (fluorophosphate glass, hereinafter referred to as comparative glass Y). This comparative glass Y had a thermal expansion coefficient of 158. It was as large as × 10 ⁻⁷ K ⁻¹ , cracking occurred during sealing, and a solid-state imaging device could not be obtained.

Next, using these obtained solid-state imaging devices, the presence or absence of a soft error was examined. Table 3 shows the results. In the table, the amount of emitted α-rays was measured with an α-ray measuring device LACS manufactured by Sumitomo Analysis Center. As is clear from Table 3, it was found that the use of the glass according to the present invention can significantly reduce the soft error.

The present invention is not limited to the above embodiment, and it goes without saying that various variations can exist as described above.

Tables 1 and 2 show various glass compositions which can be used in the present invention by weight%. In the table, the coefficient of thermal expansion is a value measured by a TMA analyzer. Each has a coefficient of thermal expansion suitable for sealing with alumina ceramic.

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

According to the present invention, it is possible to provide a glass for a package window material for a semiconductor such as a solid-state imaging device having a remarkably low soft error rate. Further, by limiting the composition to a specific composition range, it is possible to provide a glass having a good thermal expansion coefficient in bonding with the alumina ceramic package. ADVANTAGE OF THE INVENTION According to the manufacturing method of the glass of this invention, mixing of U and Th in a manufacturing process can be suppressed significantly, and the glass suitable for the window material for packages can be obtained, and the soft error caused by alpha rays from the glass can be obtained. Can be significantly reduced, which can contribute to higher resolution and higher density of semiconductors such as solid-state imaging devices. If an infrared absorbing glass having a sensitivity correction function is used as a window material for a package, the size of the CCD can be reduced, and cost reduction can be expected.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of an optical system of a VTR camera.

FIG. 2 is an explanatory diagram showing a configuration of an optical system of a VTR camera using a window glass for semiconductor package made of near-infrared absorbing glass of the present invention.

FIG. 3 is an explanatory view showing a cross section of an electric furnace used for melting glass in an example.

FIG. 4 shows a spectral transmittance curve of a window glass for semiconductor package made of the near infrared absorbing glass of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lens system 2, 3 Quartz plate 4 Near-infrared absorption filter 6, 10 Solid-state image sensor 7 CCD chip 8 Alumina ceramic package 9 Window material for package 11 Protective filter 12 Outer wall material 13 Silicon carbide heating element 14 Inner wall 15 Electric furnace

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI H04N 5/335 C03C 3/089 // C03C 3/064 3/091 3/089 3/093 3/091 H01L 27/14 D 3 / 093 31/02 B (56) References JP-A-6-211539 (JP, A) JP-A-6-211538 (JP, A) JP-A-5-343659 (JP, A) JP-A-3-16933 (JP, A) JP-A-2-221129 (JP, A) JP-A-2-22131 (JP, A) JP-A-6-329422 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) C03C 3/16 C03C 3/062 C03C 3/089

Claims (2)

(57) [Claims] 1. The composition contains 50 to 85% of P ₂ O ₅ and 4 to 20% of Al ₂ O ₃ in weight%, the total of both being 63% or more, and containing 0.1 to 10% of CuO. And contains no alkali metal oxide and has a coefficient of thermal expansion of 45 to 78 × 10 ^−7.
It consists infrared ray absorbing glass, which is a K ^-1, the semiconductor package window material glass and the content of U and Th is both 5ppb or less. 2. A solid-state imaging device comprising the window glass for a semiconductor package according to claim 1 .