JPH10321749A - Sealing method of package for solid-state image-pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for sealing a package to obtain a reliable solid- state image-pickup device package by suppressing adverse effects to the package. SOLUTION: A solid-state image-pickup device 6 is set within a cavity 2 of a package body 3 one side of which is open, so that inner leads thereof are wire-bonded. Thereafter, a sealing surface 3a of the package body 3 is coated with an ultraviolet-ray setting resin 8 and then pressed against a sealing glass 7. Subsequently, ultraviolet rays are irradiated on the surfaces of the inner leads and an image-pick device 6 through a filter 21 which functions to cut a short-wavelength region (of about 300 nm or less) where the surfaces are activated. As a result, the resin 8 is set to seal the package body 3 and the sealing glass 7 therebetween.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of sealing a package for sealing a solid-state image pickup device (hereinafter, referred to as "CCD").

[0002]

2. Description of the Related Art FIG.
FIG. 2 is a schematic cross-sectional view illustrating an example of a CD package. 3, the CCD package 1 has a package body 3 made of a resin such as an epoxy resin or a ceramic and having a cavity 2 having an opening on one surface (upper surface).
And a package body 3 die-bonded to a die attach surface 4 formed on the bottom surface of the cavity 2.
C as a solid-state imaging device wire-bonded to a lead (not shown) on the
It comprises a CD chip 6, a seal glass 7 as a lid for closing the opening of the package body 3, and the like. In addition, plastic may be used for the seal glass 7 as a lid in addition to glass.

FIG. 4 shows a CCD package 1 shown in FIG.
FIG. 4 is a process diagram showing an example of a method of performing a sealing process between a package body 3 and a seal glass 7 in FIG. Therefore,
A conventional sealing method will be described according to the order of steps 1 to 4 in FIG.

In this step, a CCD chip 6 is die-bonded to a die attach surface 4 in a cavity 2 and wire-bonded to an inner lead (not shown) of the package body 3 by a bonding wire 5. Package body 3 is prepared.
Next, the opening peripheral surface of the package body 3 (seal surface 3a)
A liquid ultraviolet (UV) curable resin 8 which cures when irradiated with ultraviolet light and functions as an adhesive is applied thereon by a dispenser 9. The size of the upper surface of the package body 3 in this example is about 10 mm, and the seal width is about 1 m.
m. As the UV-curable resin 8, a liquid UV-curable epoxy resin or the like is used.

Lid (seal glass) bonding step: Here, after positioning the seal glass 7 on the seal surface 3a of the package body 3 coated with the ultraviolet curing resin 8, the pressure P is applied from above the seal glass 7. Plus
The sealing glass 7 is pressed against the sealing surface 3a. The pressing here is performed by applying a force of about 9.8 to 29.4 N to about 0.3 to
Give for 1.0 s.

[0006] UV (ultraviolet) irradiation step: Here, the irradiation energy is 2 to 10 J at the bonding portion of the sealing surface 3 a where the sealing glass 7 is bonded with the ultraviolet curing resin 8.
Ultraviolet rays (for example, 20 to 100 s per 100 mW / cm 2) are irradiated from the ultraviolet irradiator 12 to cure the ultraviolet-curable resin 8. Then, by this curing, a substantially completed CCD package 1 is formed. In addition, the ultraviolet rays here are irradiated without limitation on the wavelength light possessed by the ultraviolet rays, from the short wavelength region where the energy is strong as shown in FIG. 5 to almost the entire wavelength region of the long wavelength region. Note that the x-axis in FIG. 5 is the wavelength (nm) and the y-axis is the relative spectral illuminance.

Post-cure (post-curing) step: Here, the entire CCD package 1 formed in the UV irradiation step is heated, and heat is applied to the ultraviolet curable resin 8 to further cure it. Thus, the CCD package 1 shown in FIG. 3 in which the sealing surface 3a and the sealing glass 7 are completely bonded is formed. The heating method used here is a heater block 11 having a built-in heater 10.
In the case where the CCD package 1 formed in the UV irradiation step is mounted on the heater block 11 and heated, heat of about 150 ° C. is applied for about 2 to 5 minutes.
As another heating method, an oven may be used. In a case where the CCD package 1 is placed in the oven and heated, heat of about 150 ° C. is applied for about 1 to 3 hours to completely adhere the sheets.

[0008]

As described above, in the conventional processing method, in the ultraviolet irradiation step, the wavelength range of the ultraviolet light is not restricted but is limited from the short wavelength region where the energy is strong to almost the entire wavelength region of the long wavelength region. Irradiation.
For this reason, there is a possibility that the surface of the inner leads on the package body 3 side and the surface of the CCD chip 6 may be activated and adversely affected, in addition to the curing of the ultraviolet curable resin 8 as a sealant. That is, if the inner leads are excessively activated, damage such as pinholes is made on the surface plating layer. When the pinholes and the like are formed, moisture that has entered the package under high-temperature and high-humidity conditions is adsorbed in the pinholes and reacts with the 42 alloy as the plating base to cause corrosion. Further, the corrosion may lead to a bridge between the inner leads, breakage of the gold (Au) wire, or the like, and thus has a problem that reliability is significantly reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a sealing method capable of obtaining a highly reliable solid-state imaging package by reducing a bad influence on the package. It is in. Further, other objects will be clarified sequentially in the contents described below.

[0010]

Means for Solving the Problems The present invention is characterized by taking the following technical means in order to achieve the above object.
That is, the solid-state imaging device is set by wire bonding with the inner lead in the cavity of the package body having one surface opened, and thereafter, the lid is pressed by applying an ultraviolet curable resin to the sealing surface of the package body,
Subsequently, the surface of the inner lead and the surface of the solid-state imaging device are irradiated with ultraviolet light toward the sealing surface through a filter having a property of cutting a short wavelength region that activates the surface of the solid-state imaging device, and the ultraviolet curable resin is irradiated with the ultraviolet light. Is cured to seal between the package body and the lid. Here, the short wavelength region to be cut is a short wavelength that activates the inner lead surface,
The wavelength is approximately 300 nm or less.

According to this, the ultraviolet light is irradiated in a state in which the surface of the package inner lead constituting the package and the short wavelength region for activating the surface of the solid-state image pickup device are cut, so that the surface of the inner lead and the solid It is possible to prevent the imaging device or the like from being activated and corroded.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, the form described below is
Although the present invention is a preferred specific example of the present invention, various technically preferable limits are given. However, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description. It is not limited to.

FIG. 1 is a process chart showing one embodiment of a method for sealing a package for a solid-state imaging device according to the present invention. In this example, the case where the CCD package 1 shown in FIG. 3 is formed is taken as an example. Therefore, the same reference numerals in FIG. 1 as those in FIG. 3 indicate the same components as those in FIG. Therefore, the sealing method of the present invention will be described in the order from the steps in FIG.

A sealant application step: First, a CCD chip 6 is die-bonded to a die attach surface 4 in a cavity 2 and wire-bonded to an inner lead (not shown) of the package body 3 by a bonding wire 5. Package body 3 is prepared.
Next, the opening peripheral surface of the package body 3 (seal surface 3a)
A liquid ultraviolet (UV) curable resin 8 that is cured by irradiation with ultraviolet light and can be used as an adhesive is applied thereon by a dispenser 9. The size of the upper surface of the package body 3 in this example is about 10 mm, and the seal width is about 1 mm. As the UV-curable resin 8, a liquid UV-curable epoxy resin or the like is used.
It is known that the ultraviolet curable resin 8 mainly reacts and cures at a wavelength near 365 nm.

Lid (seal glass) aligning step: Here, after aligning the seal glass 7 on the seal surface 3a of the package body 3 coated with the ultraviolet curing resin 8, the pressure P is applied from above the seal glass 7. Plus
The sealing glass 7 is pressed against the sealing surface 3a. The pressing here is performed by applying a force of about 9.8 to 29.4 N to about 0.3 to
Give for 1.0 s.

UV (ultraviolet) irradiation step: Here, the irradiation energy is 2 to 10 J at the position where the seal glass 7 is adhered with the ultraviolet-curing resin 8 on the sealing surface 3 a.
Ultraviolet rays (for example, 20 to 100 s per 100 mW / cm 2) are irradiated through the filter 21 to cure the ultraviolet curable resin 8. Then, the almost completed CCD package 1 is completed by this curing. In addition, the filter 21 is one of the wavelength lights of the ultraviolet light,
The short wavelength region (30
(0 nm or less). The ultraviolet light in the short wavelength region (300 nm or less) is not particularly necessary for curing the ultraviolet-curable resin 8, but is known to activate the surface of the inner lead and the surface of the solid-state imaging device. Therefore, when ultraviolet light is irradiated while the short wavelength region is cut as in the processing method of the present embodiment, the surface of the inner lead, the solid-state imaging device, and the like can be prevented from being activated and corroded. Here, the x-axis in FIG. 2 is the wavelength (nm), and the y-axis is the relative spectral illuminance.

Post-cure (post-curing) step: Here, the entire CCD package 1 formed in the UV irradiation step is heated, and heat is applied to the ultraviolet curable resin 8 to further cure it. Thus, the CCD package 1 shown in FIG. 3 in which the sealing surface 3a and the sealing glass 7 are completely bonded is formed. In this case, the heating method is as follows. A heater block 11 having a built-in heater 10 is prepared, and when the CCD package 1 formed in the UV irradiation step is mounted on the heater block 11 and heated, 150 ° C. Apply about 2-5 minutes of heat. In addition, an oven may be used as another heating method,
When the CCD package 1 is placed in an oven and heated, heat of about 150 ° C. is applied for about 1 to 3 hours to completely adhere.

Therefore, according to the structure of this embodiment, C
Ultraviolet rays are irradiated in a state where a short wavelength region (about 300 nm or less) for activating the surface of the inner lead constituting the CD package 1 and the surface of the solid-state imaging device (CCD chip 6) is cut. The surface and the solid-state imaging device are prevented from being activated and corroded, and a highly reliable package can be provided. In addition,
In the above embodiment, the case where the wavelength of about 300 nm or less is cut by the filter 21 has been described. However, the cut wavelength is changed within a range that does not affect the curing depending on the type of the sealant (ultraviolet curable resin 8) used. Depending on the type, those having a wavelength of 200 to 365 nm or less are selected, but approximately 300 nm or less is an average value.

[0019]

As described above, according to the present invention,
Since ultraviolet rays are irradiated in a state where the surface of the package inner lead constituting the package and the short wavelength region that activates the surface of the solid-state imaging device are cut, the surface of the inner lead and the solid-state imaging device are activated and corroded. And a highly reliable package can be provided.

[Brief description of the drawings]

FIG. 1 is a process diagram schematically showing one embodiment of a sealing method according to the present invention.

FIG. 2 is a diagram illustrating a wavelength region of ultraviolet light used in the present invention.

FIG. 3 is a schematic cross-sectional view of a conventionally known package structure.

FIG. 4 is a process diagram schematically showing one embodiment of a conventional sealing method.

FIG. 5 is a diagram illustrating a wavelength region of ultraviolet light used in a conventional method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 CCD (solid-state imaging device) package 2 cavity 3 package main body 3a sealing surface 5 bonding wire 6 CCD chip (solid-state imaging device) 7 sealing glass (lid) 8 ultraviolet curing resin 21 filter

Claims (2)

[Claims] 1. A solid-state imaging device is set by wire bonding with inner leads in a cavity of a package body having an opening on one side, and thereafter, a lid is pressed by applying an ultraviolet curable resin to a sealing surface of the package body, Subsequently, the surface of the inner lead and the surface of the solid-state imaging device are irradiated with ultraviolet light toward the sealing surface through a filter having a property of cutting a short wavelength region that activates the surface of the solid-state imaging device. And sealing the space between the package body and the lid by sealing the package. 2. The method according to claim 1, wherein a filter having a characteristic of cutting a short wavelength region of about 300 nm or less is used as the filter.