JP2001102470A - Semiconductor device - Google Patents

Abstract

[PROBLEMS] To improve the transmittance characteristics of ultraviolet light in a semiconductor device such as a packaged solid-state imaging device. SOLUTION: A semiconductor chip 12 such as an imaging chip is disposed in a package 13, and a cover member 14 made of quartz glass is bonded to the package 13 via a sealant 15 having a longitudinal elastic coefficient of 50 GPa or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a semiconductor device such as a solid-state imaging device.

[0002]

2. Description of the Related Art FIG. 4 shows a general configuration of a solid-state imaging device having a solid-state imaging chip arranged in a package, for example, a CCD solid-state imaging device. This CCD solid-state imaging device 1
Is a method in which a CCD imaging chip 2 is housed and arranged in a package 3 made of ceramic or plastic, and a cover member made of a light-transmitting glass material, a so-called cover glass 4 is bonded to the opening side of the package 3 via a sealant 5. It is composed. Reference numeral 6 denotes an external lead-out terminal from the package 3.

Generally, non-alkali glass or low-alkali glass is used as the cover glass 4 in the CCD solid-state imaging device 1. FIG. 5 shows the transmittance characteristics of these glass materials.

[0004]

The alkali-free glass and the low alkali glass have a visible light transmittance of about 92% as shown in the transmittance characteristics of FIG.
This is a level that can be used without any problem for the cover glass 4 of the CD solid-state imaging device. However, this alkali-free glass or low alkali glass has an extremely low transmittance of ultraviolet rays having a wavelength of 300 nm or less as low as 30% or less.
When used for the cover glass 4 of the CD solid-state imaging device, a high-sensitivity ultraviolet solid-state CCD solid-state imaging device cannot be obtained.

Therefore, it is conceivable to use quartz glass having a high ultraviolet transmittance for the cover glass 4 of the ultraviolet CCD solid-state imaging device. However, in this case, the following problem occurs.

The linear expansion coefficients of quartz glass as the cover glass 4 and ceramic or plastic constituting the package 3 are: quartz glass (cover glass 4): 5 to 7 × 10 ⁻⁷ / ° C. ceramic (package 3): 5 ８8 × 10 ⁻⁶ / ° C. Plastic (package 3): 1 to 5 × 10 ⁻⁵ / ° C. As described above, the quartz glass used as the cover glass 4 and the ceramic or plastic constituting the package 3 have significantly different linear expansion coefficients. For this reason, these are usually used with a modulus of longitudinal elasticity of 1000.
When a relatively hard epoxy adhesive such as GPa is attached as a sealant, the cover glass peels off or cracks when a thermal shock or temperature cycle is applied, and the durability of the CCD solid-state imaging device is reduced. There is a problem that it is significantly reduced.

[0007] Such a problem is not limited to the solid-state image pickup device, but also to other semiconductor devices in which another semiconductor chip is housed and arranged in a similar package and which needs to transmit ultraviolet rays into the package. It can happen.

The present invention has been made in view of the above circumstances, and provides a semiconductor device having enhanced transmittance characteristics of ultraviolet light and applied to, for example, a solid-state imaging device.

[0009]

A semiconductor device according to the present invention has a structure in which a semiconductor chip is arranged in a package, and a cover member made of quartz glass is bonded to the package via a sealant having a longitudinal modulus of elasticity of 50 GPa or less. I do. The semiconductor device of the present invention can be applied to a solid-state imaging device or another semiconductor device.

In the present invention, since the cover member of the package is formed of quartz glass, the transmittance of ultraviolet rays of 300 nm or less is increased. Also, since a relatively soft sealant having a longitudinal modulus of elasticity of 50 GPa or less is used as the sealant, even if the package is formed of ceramic or plastic, the linear heat between the cover member and the package when subjected to thermal shock or temperature cycling. The stress due to the difference in expansion is absorbed by the sealant, and the cover member does not peel or crack.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment in which the semiconductor device of the present invention is applied to a CCD solid-state imaging device. In the CCD solid-state imaging device 11 according to the present embodiment, a CCD imaging chip 12 is housed and arranged in a package 13, and a sealing agent 15 is placed on the upper end surface of the package 13 so as to cover an opening on the light receiving side of the package 13. And a cover member formed of a light-transmitting glass material, that is, a so-called cover glass 14. Reference numeral 16 denotes an external lead terminal derived from the package 13.

The package 13 is formed of ceramic (for example, having a coefficient of linear expansion of 5 to 8 × 10 ⁻⁶ / ° C.) or plastic (for example, having a coefficient of linear expansion of 1 to 5 × 10 ⁻⁵ / ° C.). The cover glass 14 is formed of quartz glass having a high ultraviolet transmittance. Furthermore, wavelengths from 240 nm to 300 n
An antireflection film (so-called AR coat film) 17 can be formed on the outer and inner surfaces of the cover glass 14 made of quartz glass so that the ultraviolet transmittance near m is 92% or more.

The antireflection film 17 may have a multilayer structure or a single-layer structure. For example, an Al ₂ O ₃ film, a Ta ₂ O ₅ film, and a MgF
_An antireflection film having a three-layer structure in which _two films are stacked can be used.

A cover glass 14 made of quartz glass and a package 13 made of ceramic or plastic or the like
As the sealant 15 for adhering to the base material, the coefficient of longitudinal elasticity is 0.1.
01 GPa or more and 50 GPa or less, preferably 1 GPa
A relatively soft sealing agent in the range of 10 GPa to 10 GPa, for example, a resin adhesive is used. If the modulus of longitudinal elasticity exceeds 50 GPa, it is difficult to absorb the stress due to the difference in linear thermal expansion between the cover glass 14 and the package when subjected to a thermal shock or a temperature cycle. Further, a sealing material having a modulus of longitudinal elasticity smaller than 0.1 GPa can be used, but it is difficult at present to produce a resin adhesive smaller than 0.1 GPa.

As the sealant 15, for example, an epoxy resin adhesive (1 GPa to 50 GPa), an acrylic resin adhesive (0.1 GPa to 50 GPa) or the like can be used. Among them, an epoxy resin-based adhesive is preferable. When using an epoxy resin-based adhesive, the modulus of longitudinal elasticity is 1 GPa to 1 in view of ease of production and stress absorption characteristics.
More preferably, it is 0 GPa. At present, 1 GPa
It is difficult to make an epoxy resin adhesive that can be used as a smaller semiconductor sealing material.

FIG. 2 shows an example of the transmittance characteristic with respect to the wavelength of quartz glass. Quartz glass has a wavelength of 240 nm to 30 nm.
Ultraviolet transmittance near 0 nm has about 90%. FIG. 3 shows an example of the ultraviolet transmittance characteristics of quartz glass having an antireflection film 17 on both surfaces.

The quartz glass having the antireflection film 17 on both sides has an ultraviolet transmittance of 92% or more at a wavelength of about 240 nm to 300 nm.

[0019] CCD solid-state imaging device 1 according to the present embodiment
According to No. 1, by forming the cover glass 14 of the package 13 from quartz glass, the wavelength is 240 nm to 300 nm.
The ultraviolet transmittance in the vicinity of nm can be reduced to about 90%. Further, in order to increase the ultraviolet transmittance of the cover glass 14, the antireflection film 17 is formed on both the outer surface and the inner surface of the quartz glass so that the wavelength is 240 nm to 30 nm.
The ultraviolet transmittance near 0 nm can be made 92% or more.

By bonding a package 13 made of ceramic or plastic and a cover glass 14 made of quartz glass with a soft sealing agent 15 of 50 GPa or less, the cover glass 14 and the cover glass 14 are subjected to a temperature cycle or thermal shock. The stress due to the difference in linear expansion coefficient from the package 13 is absorbed by the sealant 15. Therefore, it is possible to prevent the cover glass 14 from peeling off at the interface with the package 13 due to a thermal stress due to a temperature cycle, a thermal shock or the like, and to prevent the occurrence of glass breakage. As a result, a longitudinal elastic modulus of 100 generally used as a sealant is used.
The reliability against thermal shock and temperature cycling is greatly improved as compared with the case of bonding with a hard resin adhesive of about 0 GPa.

Accordingly, it is possible to provide a highly reliable and high-sensitivity CCD solid-state imaging device for ultraviolet light.

In the above example, the present invention is applied to a CCD solid-state image pickup device. However, the present invention can also be applied to a solid-state image pickup device for ultraviolet light of, for example, a CMOS type, a MOS type, or the like.

In another embodiment, the CCD image pickup chip 12 shown in FIG. 1 is replaced by another semiconductor chip, and another semiconductor device such as a light receiving semiconductor device which needs to transmit ultraviolet rays into the package 13 is required. The device can be configured. In such a semiconductor device, the transmittance characteristics of ultraviolet rays can be further improved.

[0024]

According to the semiconductor device of the present invention, the transmittance of ultraviolet rays of 300 nm or less into the package can be increased, and the reliability of the package against thermal shock and temperature cycles can be increased. Therefore, it is particularly suitable for application to, for example, an ultraviolet solid-state imaging device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a CCD solid-state imaging device according to an embodiment of the present invention.

FIG. 2 is a transmittance characteristic diagram showing an example of transmittance characteristics of quartz glass.

FIG. 3 is a transmittance characteristic diagram showing an example of transmittance characteristics of quartz glass having an antireflection film adhered to both surfaces.

FIG. 4 is a configuration diagram of a conventional general CCD solid-state imaging device.

FIG. 5 is a transmittance characteristic diagram showing an example of transmittance characteristics of non-alkali glass and low-alkali glass.

[Explanation of symbols]

11 CCD solid-state imaging device, 12 CCD imaging chip, 13 package, 14 cover glass cover glass, 15 sealant, 16 external lead-out terminal, 17 anti-reflective coating

Claims (3)

[Claims] 1. A semiconductor device wherein a semiconductor chip is arranged in a package, and a cover member made of quartz glass is bonded to the package via a sealant having a longitudinal elastic modulus of 50 GPa or less. 2. The antireflection film according to claim 1, wherein an antireflection film is formed on an outer surface and an inner surface of the cover member so that an ultraviolet ray transmittance near a wavelength of 240 nm to 300 nm is 92% or more. Semiconductor device. 3. The semiconductor device according to claim 1, wherein said semiconductor chip is a solid-state imaging chip.