JP2004327978A - Glass for semiconductor package window, glass window for semiconductor package and method for manufacturing the same, and semiconductor package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide glass for a window that can be preferably attached to a plastic semiconductor package and a glass window for the semiconductor package having various functions. <P>SOLUTION: The glass for a semiconductor package window is: (1) used for a window material of a plastic semiconductor package and the average coefficient of linear expansion at a temperature of 100 to 300°C is 120 to 180×10<SP>-7</SP>/°C; or (2) has the average coefficient of linear expansion and each contents of U and Th is less than or equal to 5ppb. Moreover, the glass for a semiconductor package window: (a) consists of the glass for a window; (b) is equipped with a lens function and has the average coefficient of linear expansion; or (c) has the average coefficient of linear expansion, and each contents of U and Th is less than or equal to 5ppb, consisting of glass containing Cu and phosphoric acid and the wavelength showing a transmittance of 50% is less than 630 nm in a spectral transmittance of the wavelength of 400 to 700 nm converted to a thickness of 0.5 mm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a glass for a window of a semiconductor package, a glass window for a semiconductor package, a method for manufacturing the same, and a semiconductor package. More specifically, the present invention relates to a glass used as a window for a plastic semiconductor package having a built-in solid-state image sensor such as a digital camera or a VTR camera, and a glass window for the semiconductor package, for example, a color of an image sensor such as a CCD. The present invention relates to a glass window for a semiconductor package having a near-infrared absorption filter function for correcting sensitivity and a method for manufacturing the same, and a semiconductor package including the glass window, a semiconductor element, and a package for housing the semiconductor element.

  Since a semiconductor such as a CCD causes a soft error due to α rays emitted from the window glass for a package, the amount of radioisotopes emitting α rays contained in the window glass for a package must be reduced. As a window glass for a semiconductor package that suppresses the emission of α rays, for example, a window glass for a semiconductor in which the contents of U and Th are suppressed to 5 ppb or less is disclosed (for example, see Patent Document 1).

  In recent years, with the miniaturization of digital cameras and the spread of camera-equipped mobile phones, high-resolution and small-sized imaging systems have been required. All components such as lenses, filters, and packages are becoming smaller and thinner. Further, not only miniaturization and thinning but also compounding has been proposed. For example, Patent Document 1 discloses a window glass for a semiconductor package that contains CuO and absorbs near-infrared wavelengths, in addition to a transparent window glass for a semiconductor package.

  By the way, the window glass of a conventional semiconductor package is adapted to the thermal expansion characteristics of a ceramic package such as alumina and has a relatively small expansion coefficient. Therefore, if the package is bonded to a plastic package, the package may be warped or deformed or the glass may be broken due to a difference in thermal expansion, which is an obstacle to reducing the weight of the package using a plastic material.

JP-A-8-306894

  Under such circumstances, the present invention provides a glass for a window that can be suitably mounted on a plastic semiconductor package, a glass window for the semiconductor package having various functions, a method for manufacturing the same, and a method for manufacturing the glass window. It is an object of the present invention to provide a semiconductor package having the same.

  The present inventor has conducted intensive studies to achieve the above object, and as a result, has a glass having a specific average linear expansion coefficient, a glass having a specific average linear expansion coefficient, and the content of U and Th is not more than a certain value. The glass can be adapted for the purpose as a window glass of a plastic semiconductor package, and a glass window for a semiconductor package made of these glasses, or for a semiconductor package having a lens function or a specific spectral transmittance. The present inventors have found that a glass window can meet the above purpose, and have completed the present invention based on this finding.

That is, the present invention
(1) A window glass for a semiconductor package (hereinafter, referred to as a window material for a semiconductor package) which is provided for a window material of a plastic semiconductor package and has an average linear expansion coefficient at 100 to 300 ° C. of 120 to 180 × 10 ⁻⁷ / ° C. Glass 1),
(2) A window glass for a semiconductor package (hereinafter, referred to as a glass package) characterized in that the average linear expansion coefficient at 100 to 300 ° C. is 120 to 180 × 10 ⁻⁷ / ° C., and the contents of U and Th are each 5 ppb or less. Glass 2)
(3) The glass for a window of a semiconductor package according to the above (1) or (2), comprising glass containing Cu and phosphoric acid.
(4) The window glass for a semiconductor package according to the above (3), wherein the wavelength showing a transmittance of 50% is less than 630 nm in the spectral transmittance at a wavelength of 400 to 700 nm converted to a thickness of 0.5 mm.
(5) by ^{cationic%, P 5+ 23~41%, Al 3+} 4~16%, Li + 11~40%, Na + 3~13%, R 2+ 12~53% (R 2+ is ^Mg 2+, Ca ^{2+, Sr 2+, Ba 2+,} Zn 2+), along with containing Cu 2+ 2.6~4.7%, F as an anion component ^- and ^{O 2-} and containing the (3) or (4) according to claim Glass for semiconductor package windows,
(6) A glass window for a semiconductor package (hereinafter, referred to as a glass window 1) made of the glass for a window according to any one of the above items (1) to (5);
(7) A glass window for a semiconductor package (hereinafter, referred to as a glass window 2) having a lens function and having an average coefficient of linear expansion at 100 to 300 ° C. of 120 to 180 × 10 ⁻⁷ / ° C.
(8) An average linear expansion coefficient at 100 to 300 ° C. is 120 to 180 × 10 ⁻⁷ / ° C., the content of U and Th is 5 ppb or less, respectively, and the glass is made of Cu and phosphoric acid. A glass window for a semiconductor package (hereinafter, referred to as a glass window 3) characterized in that a wavelength showing a transmittance of 50% is less than 630 nm in a spectral transmittance of a wavelength of 400 to 700 nm converted to 0.5 mm and having a flat plate shape. .),
(9) The glass window for a semiconductor package according to any one of the above (6) to (8), which is a precision press-molded product,
(10) A method for manufacturing a glass window for a semiconductor package, which comprises precision press-molding a lens-shaped window glass made of glass having an average linear expansion coefficient at 120 to 180 × 10 ⁻⁷ / ° C. at 100 to 300 ° C. ,
(11) A glass window for a semiconductor package according to any one of the above items (6) to (9) or a glass window for a semiconductor package manufactured by the manufacturing method according to the above item (10), and a semiconductor element And a package for accommodating a semiconductor element, wherein the mounting portion of the glass window is made of a plastic material. (12) The semiconductor device according to the above (11), wherein the semiconductor element is an imaging element. Semiconductor package,
Is provided.

  According to the present invention, it is possible to provide a glass for a window of a semiconductor package which can be favorably mounted on a plastic package, a glass window for a semiconductor package, a method for manufacturing the same, and a semiconductor package having the glass window.

In the present invention, the window glass means glass used for a material of a window attached to a semiconductor package, and the glass window means a glass window attached to a semiconductor package. Window glass is roughly classified into glass 1 and glass 2 as follows.
[Glass 1]
The glass 1 is used as a window material of a plastic semiconductor package, and has an average linear expansion coefficient at 100 to 300 ° C. of 120 × 10 ^{−7 to} 180 × 10 ⁻⁷ / ° C., preferably 135 × 10 ^{−7 to} 180 ×. The glass is 10 ⁻⁷ / ° C., more preferably 140 × 10 ^{−7 to} 180 × 10 ⁻⁷ / ° C.
According to the glass 1, by setting the average coefficient of linear expansion in the above range, warping and deformation of the package and breakage of the glass can be prevented even when the package is bonded to a plastic package. Further, it is possible to provide a window having higher durability and homogeneity than a plastic window.
The package also includes the entire package for housing the semiconductor element, or a frame for fixing the window to the semiconductor element, or the above-described frame having a function of sealing the light receiving surface of the semiconductor element using the window. . Hereinafter, the term “package” means the above package.

[Glass 2]
Glass 2 has an average linear expansion coefficient at 100 to 300 ° C. is 120 to 180 × ^{10 -7} / ° C., preferably ^{135 × 10 -7 ~180 × 10 -7} / ℃, more preferably 140 × ¹⁰ -7 to 180 × 10 ⁻⁷ / ° C., and the content of U and Th is 5 ppb or less, respectively.
According to the glass 2, by setting the average coefficient of linear expansion in the above range, warping and deformation of the package and breakage of the glass can be prevented even when the package is bonded to a plastic package. Further, since both the contents of U and Th are 5 ppb or less, it is possible to provide a semiconductor package free from soft errors due to α-ray emission from the glass window. Thereby, the glass window can be arranged close to the semiconductor element, and the package can be reduced in size and weight.
The glass for a window of the semiconductor package of the present invention preferably has both the characteristics of the above-mentioned glass 1 and glass 2.

In order to give the window glass a high expansion characteristic having an average linear expansion coefficient of 120 to 180 × 10 ⁻⁷ / ° C. at 100 to 300 ° C., it is necessary to use an alkali metal oxide or fluorine, or both an alkali metal oxide and fluorine. Is preferably introduced. The amounts of the alkali metal oxide and fluorine to be introduced can be determined in consideration of the above-mentioned expansion coefficient, weather resistance and the like.

  Whether the weather resistance is good or bad can be determined by holding the glass sample whose surface has been polished at a temperature of 60 ° C. and a humidity of 80% RH for 1000 hours and then examining whether the polished surface of the sample has deteriorated such as burns. . In other words, glass having good weather resistance does not show any surface deterioration even after the above-mentioned weather resistance test, and can be sufficiently used as window glass. On the other hand, the surface of other glass samples is deteriorated and cannot be used as window glass. The quality of the weather resistance can also be determined based on the change in the spectral transmittance before and after the weather resistance test. The maximum value of the spectral transmittance at a wavelength of 400 to 700 nm is compared before and after the test. If the maximum value of the spectral transmittance after the test is 90% or more of the maximum value of the spectral transmittance before the test, good weather resistance is obtained. It can be said that it shows the nature. When measuring the spectral transmittance, a sample polished so that both surfaces are parallel to each other is used. Since the spectral transmittance also includes light loss on the sample surface, it is possible to compare the state of the sample surface before and after the test.

  As the window glass, those having a glass transition temperature of 550 ° C. or less are preferable. According to such a low transition temperature glass, a glass window can be produced by precision press molding. The light input / output surface of the glass window is formed into a lens shape by precision press molding, and a pattern for providing the light input / output surface with a function as a diffraction grating or a pattern for providing a function as an optical low-pass filter is produced. It can be formed well.

From the viewpoint of the glass composition, phosphoric acid-containing glass (for example, fluorophosphate glass, phosphate glass), glass containing SiO ₂ and an alkali metal oxide are suitable as the window glass. According to these glasses, it is easy to obtain a homogeneous glass. As the window glass, fluorophosphate glass is particularly preferred.
Phosphoric acid-containing glass (fluorophosphate glass, phosphate glass) is a glass containing phosphoric acid as a main component, and a specific description thereof will be given later.

As the glass containing SiO ₂ and the alkali metal oxide, a glass containing SiO ₂ , TiO ₂ , and an alkali metal oxide is preferable. As a specific composition, glass in which SiO ₂ , TiO ₂ , and an alkali metal oxide are essential components and the total amount of the essential components is 60 mol% or more is preferable, and SiO _{2 is} 38 to 58% in terms of mol%. , _TiO 2 _7~30%, 15~40% of alkali metal oxides in total, glass containing _Al 2 O 3 _0~12% is more preferable. Among them, Na ₂ O 10-25%, K ₂ O 4-15%, MgO 0-13%, CaO 0-10%, SrO 0-8%, BaO 0-6%, ZnO 0-10%, Sb ₂ O ₃ is more preferably those containing 0 to 1%, MgO content of 1 to 13%, ZnO content of those are especially preferred 0.5 to 10%. In the above composition range, an optical constant having a refractive index (nd) of about 1.6 and an Abbe number (νd) of about 36 to 37 can be obtained.
In addition, although alkali metal oxides and fluorine both have a function of increasing the expansion coefficient, phosphoric acid-containing glasses (fluorophosphate glass and phosphate glass) are more preferable in that they do not adversely affect weather resistance. Such a glass will be described later in detail.

  In order to impart the color correction filter function of the semiconductor imaging device to the window glass, it is preferable to introduce Cu into the glass to have near-infrared absorption characteristics. As such a window glass having a color correction filter function, it is preferable to use a glass containing Cu and phosphoric acid (fluorophosphate glass or phosphate glass). In terms of transmittance, it is more preferable to use glass whose wavelength showing a transmittance of 50% is less than 630 nm.

Furthermore, since the window glass is disposed close to the semiconductor image pickup device, it is important to keep the size and the amount of platinum foreign matter in the glass at a level lower than that of ordinary optical glass. The reason for this is that if there is a foreign substance such as platinum particles in the window glass, the shadow of the foreign substance is reflected on the image pickup device, or the image is blurred due to diffraction or the like by the foreign substance. Although foreign substances are managed even by a glass optical element such as a lens generally used, these optical elements are used away from the image pickup element, so that the image quality is not deteriorated due to the reflection of foreign substances and diffraction as compared with the window glass. In the window glass of the present invention, the number of platinum foreign particles having a particle size of 2 μm or more is preferably 10/100 ml or less, and more preferably no platinum foreign material having a particle size of 2 μm or more is contained. Prevention of platinum foreign matter is also preferable from the viewpoint of reducing the amount of radioactive substances such as U and Th mixed.
In addition, when introducing not only platinum foreign matter but also Cu, it is desirable not to precipitate Cu metal particles or Cu compound particles. The window glass is preferably made of an amorphous phase.

Next, the composition of a glass particularly suitable as a Cu-containing glass will be described. The composition is represented by P ⁵⁺ 23 to 41%, Al ³⁺ 4 to 16%, Li ⁺ 11 to 40%, Na ⁺ 3 to 13%, R ²⁺ 12 to 53% (R ²⁺ is Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Zn ²⁺ ), Cu ²⁺ 2.6 to 4.7%, and those containing F ⁻ and O ²⁻ as anion components. Hereinafter, the ratio of the cation is represented by% cation, and the ratio of the anion is represented by% anion.

P ⁵⁺ is a basic component of fluorophosphate glass, and is an important component that provides infrared absorption. If it is less than 23%, the color may be deteriorated and become greenish. On the other hand, if it exceeds 41%, the weather resistance and the devitrification resistance tend to be deteriorated. Thus the content of ^{P 5+} is preferably 23 to 41%.

Al ³⁺ is an important component for improving the devitrification resistance of fluorophosphate glass. If it is less than 4%, the devitrification resistance is poor, the liquidus temperature is high, and the melting and molding of high quality glass may be difficult. Conversely, if it exceeds 16%, the devitrification resistance may deteriorate. Therefore, the content of Al ³⁺ is preferably 4 to 16%.

Li ⁺ is a useful component for improving the devitrification resistance of glass, but if it is less than 11%, its effect is insufficient, and if it exceeds 40%, the durability and workability of the glass may be deteriorated. . Therefore, the content of Li ⁺ is preferably 11 to 40%.

Na ^{+ is} also a useful component for improving the devitrification resistance of the glass, but if it is less than 3%, its effect is insufficient, and if it exceeds 13%, the durability and workability of the glass may deteriorate. . Therefore, the content of Na ⁺ is preferably 3 to 13%.

R ²⁺ (Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Zn ²⁺ ) is a useful component for improving the devitrification resistance, durability, and processability of fluorophosphate glass. If the total of R ²⁺ is less than 12%, the devitrification resistance and durability of the glass are liable to deteriorate, while if it exceeds 53%, the devitrification resistance may deteriorate. Therefore, the content of R ²⁺ is preferably 12 to 53%.

The preferred range of Mg ²⁺ is 3-5%, the preferred range of Ca ²⁺ is 6-9%, the preferred range of Sr ²⁺ is 5-8%, the preferred range of Ba ²⁺ is 3-6%, and the preferred range of Zn ²⁺ is The range is 0-3%.

When Cu ²⁺ is less than 2.6%, infrared absorption is small, and when the transmittance converted to a thickness of 0.5 mm is in the range of 400 to 700 nm, the wavelength showing 50% transmittance may be longer than 630 nm. . On the other hand, when the content exceeds 4.7%, the devitrification resistance is deteriorated. Therefore, the content of Cu ²⁺ is preferably 2.6 to 4.7%.

O ²⁻ is a particularly important anion component in the window glass. If it is less than 52%, divalent Cu ²⁺ is reduced to monovalent Cu ⁺ , so that absorption in a short wavelength region, particularly around 400 nm, tends to increase, and the color becomes green. Therefore, the content of O ²⁻ is preferably 52 to 75%.

F ⁻ is an important anion component that lowers the melting point of glass and improves weather resistance. When the window material glass contains F ⁻ , the melting temperature of the glass can be lowered, and the amounts of U, Th, and platinum foreign matter entering from the furnace wall, refractory, or heat-resistant container during melting can be easily suppressed. If it is less than 25%, the weather resistance is insufficient, and if it exceeds 48%, the content of O ²⁻ decreases, which causes coloring at around 400 nm due to monovalent Cu ⁺ . Therefore, the content of F ⁻ is preferably 25 to 48%.

^{K +, Zr 4+, La 3+} , Gd 3+, Y 3+, Si 4+, B 3+, Sb 3+, Ce 4+ improvement of the devitrification resistance, the adjustment of the glass viscosity, adjustment of the transmittance, used as appropriate for the purposes of refining However, the total amount of the cations is preferably less than 5%, more preferably less than 1%, and even more preferably not introduced.

The preferred composition ranges in the above composition ranges are shown below.
(Preferred range 1)
As an anion component, P ⁵⁺ 23 to 41%, Al ³⁺ 4 to 16%, Li ⁺ 11 to 40%, Na ⁺ 3 to 13%, R ²⁺ 12 to 53% (R ²⁺ is Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Zn ²⁺ ), Cu ²⁺ 2.6 to 4.7%, a fluorophosphate glass containing 25 to 48% of F ^{− and} 52 to 75% of O ²⁻ as an anionic component.
(Preferred range 2)
^{Fluorophosphoric} acid having a total content of P ⁵⁺ , Al ³⁺ , Li ⁺ , Na ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Zn ²⁺ , Cu ²⁺ , and Sb ³⁺ of 99 cation% or more, more preferably 100 cation%. Glass.
(Preferred range 3)
A fluorophosphate glass in which the total amount of F ⁻ and O ²⁻ is 100 anion%.
(Preferred composition range 4)
Fluorophosphate glass containing no Pb, As or Cd. The glass containing no Pb, As, or Cd is not limited to fluorophosphate glass, but is preferably used for any of the window materials 1 to 3.

According to the fluorophosphate glass, an optical constant having a refractive index (nd) of around 1.5 and an Abbe number (νd) of around 74.5 can be obtained. Therefore, when designing the lens shape, the optical constants may be referred to.
Phosphoric acid-containing glass such as phosphate glass or fluorophosphate glass generally has poor chemical durability and cannot withstand, for example, a weathering test for 1000 hours in an environment of 60 ° C. and 80% RH. Is eroded, causing cloudiness and roughness. However, the above glass is excellent in chemical durability, withstands a weather resistance test maintained at 60 ° C. and 80% RH for 1000 hours, and is sufficiently used as window glass. Possible surface conditions can be maintained.

Next, a method for manufacturing the window glass will be described.
It is desirable to use a raw material having a U and Th content of 1 ppb or less as a glass raw material for window glass. For example, using raw materials such as phosphates, fluorides, carbonates, nitrates, and oxides as appropriate, weighing the raw materials to a desired composition, mixing them, and then using a heat-resistant crucible, for example, to 800 to 900 ° C. To dissolve. The material of the heat-resistant crucible is preferably quartz or platinum having a very low U and Th content. Particularly preferably, the raw material is roughly melted in a quartz crucible and then completely melted in a platinum crucible. Thereby, generation of platinum foreign matter is suppressed. When dissolving the fluorine-containing glass, it is desirable to use a heat-resistant lid made of quartz, platinum, or the like in order to suppress volatilization of the fluorine component. Further, the melting atmosphere is not problematic in the air, but in the case of Cu-containing window glass, it is preferable to use an oxygen atmosphere or to bubble oxygen into the molten glass in order to suppress a change in the valence of Cu. The melting temperature is preferably lower in order to suppress intrusion of U, Th, and platinum foreign matter from a furnace wall, a refractory, a melting crucible, and the like. After stirring and refining the glass in the molten state, the glass is poured out to form window glass.

As a method of forming the window glass, a conventionally used method such as casting, pipe outflow, roll, and press can be used, but large and thick glass is particularly preferable. The formed glass material is transferred to an annealing furnace which has been heated near the transition point of the glass in advance, and is gradually cooled to room temperature.
The obtained glass material is subjected to high-precision slicing, grinding, and polishing to form a glass window.

Next, a glass window for a semiconductor package will be described. The glass window of the present invention is roughly classified into glass windows 1 to 3.
[Glass window 1]
The glass window 1 is made of any of the above-mentioned window glasses. To provide a glass window that can be favorably attached to a package by utilizing the characteristics of each glass, prevent the effects of radiation, and provide a near-infrared absorption function, by configuring the glass window with the window glass. Can be.

[Glass window 2]
The glass window 2 has a lens function, and has an average linear expansion coefficient at 100 to 300 ° C. of 120 × 10 ^{−7 to} 180 × 10 ⁻⁷ / ° C., preferably 135 × 10 ^{−7 to} 180 × 10 ⁻⁷ / ° C. It is more preferably 140 × 10 ^{−7 to} 180 × 10 ⁻⁷ / ° C.
According to the glass window 2, even if the glass window 2 is bonded to a plastic package, it is possible to prevent the package from being warped or deformed or to break the glass. Further, since a lens function is provided, a part or all of an imaging optical system that forms an image on a light receiving surface of a semiconductor imaging device that accommodates light transmitted through a glass window in a package can be configured by the glass window. Therefore, it is possible to reduce the number of components and to prevent a decrease in the amount of light to be detected on the light receiving surface of the semiconductor imaging device.
The lens function is provided by molding a glass window into a lens shape, for example, a convex meniscus lens, a concave meniscus lens, a plano-convex lens, a plano-concave lens, or the like, or by forming a diffraction pattern on the surface of window glass. Or by forming a refractive index distribution.

[Glass window 3]
Glass window 3 has an average linear expansion coefficient at 100 to 300 ° C. is 120 to 180 × ^{10 -7} / ° C., preferably ^{135 × 10 -7 ~180 × 10 -7} / ℃, more preferably 140 × ^{10 -7} ~ 180 × 10 ⁻⁷ / ° C., both U and Th contents are 5 ppb or less, made of glass containing Cu and phosphoric acid, and transmitted at a spectral transmittance of a wavelength of 400 to 700 nm converted to a thickness of 0.5 mm. It is a glass window for a semiconductor package in a flat plate shape having a wavelength of less than 630 nm showing a ratio of 50%. Examples of the glass containing Cu and phosphoric acid include Cu-containing fluorophosphate glass and Cu-containing phosphate glass, but Cu-containing fluorophosphate glass is more suitable.

  By containing Cu, the glass window 3 imparts near-infrared absorption characteristics and the above-described spectral transmittance characteristics, thereby exhibiting a color correction filter function of the semiconductor imaging device. Another feature is the flat shape. Due to the above-mentioned spectral transmittance characteristics, a function as a color correction filter of a semiconductor imaging device which is sufficient even if the thickness is reduced is shown. Furthermore, since it has the above-mentioned thermal expansion characteristics, even if it is bonded to a plastic package with a thin plate, no warpage, deformation or cracking of the glass occurs, which is suitable for making the glass window thinner and smaller and lighter.

In the case of the glass window 3 and the flat shape of the glass window 1 and the glass window 2, the thickness is preferably 0.1 to 0.8 mm, more preferably 0.3 to 0.6 mm.
The glass window for a semiconductor package of the present invention has both the features of the glass window 1 and the glass window 2, the combination of the features of the glass window 1 and the glass window 3, and the features of the glass window 2 and the glass window 3. It is preferable to use one having the characteristics of the glass windows 1 to 3.

Next, common points of the glass windows 1 to 3 will be described.
The glass window is preferably a precision press-molded product. Precision press molding is a glass molded product produced by precision press molding glass in a plastically deformable state.Precision press molding is the precise transfer of the molding surface of a press mold to the above glass This is a molding method for producing an optically functional surface. The optical function surface is a surface used for reflecting, refracting, diffracting, and transmitting a light beam to be controlled, and corresponds to a light entrance / exit surface of a glass window. According to the precision press molding, a sufficient function can be obtained without performing mechanical processing such as grinding and polishing on the optical function surface. Precision press molded products include glass windows that also serve as aspheric lenses such as convex meniscus lenses, concave meniscus lenses, plano-convex lenses, and plano-concave lenses, and glass that also serves as spherical lenses such as convex meniscus lenses, concave meniscus lenses, plano-convex lenses, and plano-concave lenses. A window, a glass window also serving as a Fresnel lens, a glass window having a pattern having a low-pass filter function formed on the surface thereof, and a flat glass window may be used.

Each glass window is suitable as a glass window of a plastic package. The material of the plastic package is not particularly limited, but an epoxy-based resin containing a glass filler or the like can be exemplified as a material capable of good packaging. Details of the package material will be described later.
The glass composition suitable for the glass windows 1 to 3 is the same as that suitable for the window glass. The same applies to the case where Cu is introduced when imparting near-infrared absorption properties, and the case where phosphoric glass or fluorophosphate glass is preferred when Cu is introduced.

  In the glass window 3, as described above, the content of U and Th is 5 ppb or less, preferably 3 ppb or less, but the content of U and Th in the glass windows 1 and 2 is also 5 ppb or less. And more preferably 3 ppb or less. By using such a glass window, it is possible to provide a semiconductor package free of soft errors due to α-ray emission from the glass window. Thereby, the glass window can be arranged close to the semiconductor element, and the package can be reduced in size and weight. By setting the contents of U and Th to extremely low levels as described above, it is possible to prevent a soft error from occurring even when a semiconductor image pickup device having a large number of pixels is used. The above package is suitable for a semiconductor package having an image sensor having 1,000,000 pixels or more, more preferably a semiconductor package having an image sensor having 1.5 million pixels or more, and has a built-in image sensor having 2 million pixels or more. It is more suitable for a semiconductor package to be manufactured.

Next, a method for manufacturing a glass window for a semiconductor package by precision press molding according to the present invention will be described. In the above method, the average linear expansion coefficient at 100 to 300 ° C. is 120 × 10 ^{−7 to} 180 × 10 ⁻⁷ / ° C., preferably 135 × 10 ^{−7 to} 180 × 10 ⁻⁷ / ° C., and more preferably 140 × 10 ^−7. It is characterized in that a lens-shaped window glass made of glass at ^{−7 to} 180 × 10 ⁻⁷ / ° C. is precision press-molded.

In this method, first, a preform having a weight equal to the weight of the press-formed product is formed. For forming a preform, a glass block obtained by forming a molten glass is machined to a predetermined weight, or a predetermined weight of molten glass is formed into a preform shape while the glass is in a softened state. Can be used. A thin film may be appropriately formed on the preform surface so as to obtain good precision press moldability. Next, the preform is reheated and precision press-molded using a press mold. The molding surface of the press mold is precisely processed into a shape that is the inverse of the lens surface shape, and the shape of the molding surface is precisely transferred to glass by press molding, and a precision press molded product having a lens shape is obtained. The precision press molding is desirably performed in a non-oxidizing atmosphere such as nitrogen or a mixed gas of nitrogen and hydrogen. As the press forming die, a die made of a cemented carbide or SiC, or a die provided with a release film such as a carbon film or a noble metal alloy film on a forming surface can be used. The reheating, pressing, and cooling of the precision press molded product may be performed by a known method, and the conditions of each step may be appropriately set in accordance with the shape and size of the precision press molded product.
Thus, the glass window can be formed. The precision press-molded product may be subjected to centering if necessary, or an antireflection film may be provided on the optical function surface. In addition to the lens shape, a pattern exhibiting an optical low-pass filter function may be provided on the surface of the glass window by precision press molding.

Next, the semiconductor package of the present invention will be described. The semiconductor package of the present invention is a glass window manufactured by the manufacturing method using the glass window or the precision press molding, a semiconductor element receiving light incident from the glass window, and a plastic package containing the semiconductor element. It is characterized by having. The semiconductor element is preferably a solid-state image sensor such as a CCD or a CMOS. The package may be entirely made of plastic, but at least the glass window mounting portion is made of a plastic material.
The package is a package that houses the semiconductor element, a member that covers the light receiving portion of the semiconductor element together with the glass window, or a frame for fixing the glass window to the semiconductor element, or a light receiving section of the semiconductor element together with the glass window. The above-mentioned frame having a sealing function is also included.

The material of the plastic package is not particularly limited, and various materials can be used. Specifically, thermosetting resins such as epoxy resins (bisphenol A epoxy resin, novolak epoxy resin, glycidylamine epoxy resin, etc.), polyimide resins, phenol resins, unsaturated polyester resins, silicone resins, etc. Thermoplastic resins such as resin, liquid crystal polymer, polyphenylene sulfide resin, and polysulfone resin can be used. In addition, a curing agent, a curing accelerator, a moisture absorbent, a filler, a flame retardant, a pigment, a release agent, and an inorganic filler can be added to these resins. Among these, an epoxy resin containing a glass filler can be mentioned as one that can be favorably packaged. The method for attaching the glass window to the package is not particularly limited, and examples thereof include bonding using an ultraviolet curable resin.
According to the above-described semiconductor package, warping / deformation of the package and breakage of the glass can be prevented even when the package and the glass window are bonded by matching the thermal expansion characteristics of the glass window and the package or the glass window attachment portion of the package. .

Further, even when the glass window is made thin, warpage or breakage of the glass can be prevented. Also. Even when a glass window having a lens function is used, the glass window is not distorted, so that good imaging performance can be obtained.
Further, by using the Cu-containing glass for the glass window, the glass window performs a color correction filter function, so that the number of parts can be reduced. Similarly, the number of components can be reduced by providing a lens function to the glass window, or by providing a lens function and a color correction filter function, and the size and weight of the apparatus can be reduced.

In addition, it is desirable to pay sufficient attention to the mixing of radioactive substances in the package material as in the case of the window glass.
In addition to the glass window, an optical system for forming an image of a subject on the light receiving section of the semiconductor imaging device can be attached to the package. These optical systems are constituted by one or a plurality of lenses, and according to a known optical design method depending on whether or not the glass window has a lens function, a lens shape when a material having desired optical characteristics is used, It is good to decide the arrangement of the lenses. It should be noted that an aperture can be added to the above optical system as needed. Further, it is preferable to use a glass material for the lens constituting the optical system, similarly to the window material. Further, the average linear expansion coefficient at 100 to 300 ° C. is 120 × 10 ^{−7 to} 180 × 10 ⁻⁷ / ° C., preferably 135 × 10 ^{−7 to} 180 × 10 ⁻⁷ / ° C., and more preferably 140 × 10 ^−7. Glass having a temperature of １８０180 × 10 ⁻⁷ / ° C. is preferred. Furthermore, glass containing phosphoric acid (phosphoric acid glass, fluorophosphate glass), glass containing SiO ₂ and an alkali metal oxide, and having a glass transition temperature of 600 ° C. or less is preferable.

  Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 6
Raw materials such as phosphates, fluorides, carbonates, nitrates, and oxides were weighed and mixed so that the compositions shown in Tables 1 and 2 were obtained, mixed, and then dissolved in a platinum crucible. The glasses of Examples 1 to 5 melted at 800 to 900 ° C, and the glass of Example 6 melted at 1300 ° C. Note that Cu was not introduced into the glass of Example 6.
After stirring and refining the glass, the glass was poured into an iron plate shape, and a glass block having the composition shown in Tables 1 and 2 was formed. The glass block was transferred to a furnace heated near the glass transition point and annealed to room temperature. Samples for various measurements were cut out from the obtained glass block, and various properties were determined as described below. The results are shown in Tables 1 and 2.
(1) Average linear expansion coefficient The average linear expansion coefficient at 100 to 300 ° C. was measured based on the Japan Optical Glass Industrial Association Standard JOGIS-08.
(2) Spectral Transmittance Spectral transmittance was measured with a spectrophotometer on a 0.5 mm-thick plate-shaped glass sample polished on both surfaces parallel to each other, and each parameter was calculated. Since each glass is homogeneous, the transmittance at an arbitrary thickness can be calculated by a known method based on the transmittance measured with a sample having a thickness of 0.5 mm. The spectral transmittance includes the reflection loss at the sample surface.
(3) U and Th contents U and Th contents were measured using an ICP mass spectrometer.
(4) Weather Resistance A weather resistance test was performed on the polished sample at a temperature of 60 ° C. and a humidity of 80% RH for 1000 hours, and then the surface was observed to evaluate the weather resistance.
(5) Number Density of Platinum Foreign Material The sample was observed under magnification using an optical microscope, the number of mixed particles having a particle size of 2 μm or more was counted, and the number density was determined from the number of counted foreign materials and the volume of the observation region.

各実施例のガラスとも、１００〜３００℃における平均線膨張係数は１４０〜１８０×１０^−７／℃の範囲にあり、ＵおよびＴｈの含有量はともに５ｐｐｂ未満である。また、白金異物を含め、粒子径２μｍ以上の異物は認められなかった。さらに、Ｃｕ金属粒子、Ｃｕ化合物粒子、結晶相なども認められなかった。
耐候性試験の結果、各実施例のガラスともヤケなどの表面変質は認められなかった。また、試験後の分光透過率の最大値は、試験前における分光透過率の最大値の９０％よりも大きい値を保っていた。
実施例１〜５のガラスについては、厚さ０．５ｍｍに換算した波長４００〜７００ｎｍの分光透過率において、透過率５０％を示す波長は６３０ｎｍ未満であった。

In each of the glasses of the examples, the average linear expansion coefficient at 100 to 300 ° C. is in the range of 140 to 180 × 10 ⁻⁷ / ° C., and the contents of U and Th are both less than 5 ppb. In addition, no foreign matter having a particle diameter of 2 μm or more was found, including platinum foreign matter. Further, Cu metal particles, Cu compound particles, crystal phases, and the like were not found.
As a result of the weather resistance test, no surface deterioration such as burns was observed in any of the glasses of the examples. The maximum value of the spectral transmittance after the test was larger than 90% of the maximum value of the spectral transmittance before the test.
With respect to the glasses of Examples 1 to 5, the wavelength at which the transmittance was 50% was less than 630 nm in the spectral transmittance at a wavelength of 400 to 700 nm converted to a thickness of 0.5 mm.

Example 7
The glass of Example 1 was adhered to a plastic package having a built-in CCD having 2 million effective pixels by using an ultraviolet curable resin to produce a semiconductor package. The material of the package was an epoxy resin containing a glass filler, and the coefficient of thermal expansion was 150 × 10 ⁻⁷ / ° C. The semiconductor package to which the window glass was bonded was subjected to a heat cycle test at −40 ° C. to + 120 ° C. When the state of the glass after 100 cycles was observed, no damage was found in any of the window glass, the package, and the bonded portion. When the optical system was arranged so that an image was formed on the CCD light receiving surface in the semiconductor package, and the image taken by the CCD was observed, no soft error was observed, and faithful color reproduction was achieved by good color correction. It was confirmed that good image quality was obtained. Note that good results were similarly obtained using the window glass of Examples 2 to 5. Although the window glass of Example 6 did not contain Cu and thus did not have a color correction filter function, it was a good glass window for a semiconductor package.
Further, for each of the glasses obtained in Examples 1 to 6, the same method as described above was used except that a plastic package (the material is the same as the above material) having a CMOS image pickup device was used instead of the plastic package with a built-in CCD. Was repeated to produce a semiconductor package, and good results were obtained as in the case of the CCD built-in package.
Specific examples of such a semiconductor package include a digital camera having a built-in semiconductor imaging device such as a CCD and a CMOS, and a camera-equipped mobile phone also having a built-in semiconductor imaging device such as a CCD and a CMOS.

Example 8
Preforms made of each of the glasses of Examples 1 to 6 were molded, and the preforms were reheated to produce an aspheric lens by precision press molding. This aspherical lens was adhered and fixed as a glass window to the package with a built-in CCD used in Example 6 to produce a semiconductor package. Next, when an image forming optical system including the above-mentioned glass window was formed and a subject image was formed on the light receiving surface of the CCD and the image was observed, a good image quality could be obtained. When each of the glasses of Examples 1 to 5 is used, good color reproduction can be realized without using a color correction filter having near infrared absorption characteristics separately. According to this embodiment, the number of components can be reduced by using a glass window as a lens.
Further, for each of the glasses obtained in Examples 1 to 6, the same method as described above was used except that a plastic package (the material is the same as the above material) having a CMOS image pickup device was used instead of the plastic package with a built-in CCD. Was repeated to produce a semiconductor package, and good results were obtained as in the case of the CCD built-in package.
Specific examples of such a semiconductor package include a digital camera having a built-in semiconductor imaging device such as a CCD and a CMOS, and a mobile phone with a camera also having a built-in semiconductor imaging device such as a CCD and a CMOS, as in the seventh embodiment. Can be shown.

The glass window for a semiconductor package of the present invention can reduce soft errors due to α-ray emission and effectively prevent package warpage / deformation and glass breakage due to a difference in thermal expansion from a plastic package. It can be suitably used for a package.

Claims (12)

A window glass for a semiconductor package, which is used as a window material of a plastic semiconductor package and has an average linear expansion coefficient at 100 to 300 ° C. of 120 to 180 × 10 ⁻⁷ / ° C. A window glass for a semiconductor package, wherein the average linear expansion coefficient at 100 to 300 ° C. is 120 to 180 × 10 ⁻⁷ / ° C., and the contents of U and Th are each 5 ppb or less. 3. The glass for a window of a semiconductor package according to claim 1, which is made of a glass containing Cu and phosphoric acid. The glass for a window of a semiconductor package according to claim 3, wherein a wavelength showing a transmittance of 50% is less than 630 nm in a spectral transmittance of a wavelength of 400 to 700 nm converted into a thickness of 0.5 mm. By ^{cationic%, P 5+ 23~41%, Al 3+} 4~16%, Li + 11~40%, Na + 3~13%, R 2+ 12~53% (R 2+ is ^{Mg 2+, Ca} 2+, Sr ^{2+, Ba 2+, Zn 2+)} , Cu 2+ 2.6~4.7% with including, F as an anion component ^- and ^O window glass of the semiconductor package according to claim 3 or 4 including ^2-. A glass window for a semiconductor package comprising the window glass according to claim 1. A glass window for a semiconductor package having a lens function and having an average coefficient of linear expansion at 100 to 300 ° C. of 120 to 180 × 10 ⁻⁷ / ° C. The average linear expansion coefficient at 100 to 300 ° C. is 120 to 180 × 10 ⁻⁷ / ° C., the content of U and Th is 5 ppb or less, respectively, made of glass containing Cu and phosphoric acid, and having a thickness of 0.5 mm. What is claimed is: 1. A glass window for a semiconductor package, wherein a wavelength showing a transmittance of 50% is less than 630 nm in a spectral transmittance of a wavelength of 400 to 700 nm converted into a wavelength and having a flat plate shape. The glass window for a semiconductor package according to any one of claims 6 to 8, which is a precision press-molded product. A method for manufacturing a glass window for a semiconductor package, comprising: precision press-molding a lens-shaped window glass made of glass having an average linear expansion coefficient of 120 to 180 × 10 ⁻⁷ / ° C. at 100 to 300 ° C. A glass window for a semiconductor package according to any one of claims 6 to 9 or a glass window for a semiconductor package manufactured by the manufacturing method according to claim 10, a semiconductor element, and a package for housing the semiconductor element. A semiconductor package, wherein a mounting portion of the glass window is made of a plastic material. The semiconductor package according to claim 11, wherein the semiconductor element is an image sensor.