JP2008016693A - Method of sealing solid-state imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of sealing a solid-state imaging device by which the solid-state imaging device is hermetically sealed by a cover glass without separation of the cover glass. <P>SOLUTION: With the cover glass 5 pasted to the top face 4 of a side wall 4, light is irradiated. Then, a small quantity of light curing resin 12 applied to the top face 13 except for a cutout 11 is hardened. At that time, the resin 12 applied to the cutout 11 is not cured yet since the light curing resin 12 applied to the cutout 11 is in great amounts, and therefore a ventilation hole is secured and the inside of the cover glass 5 can be ventilated. Since there is no difference in pressure between outside and inside of the cover glass 5, the cover glass 5 is never separated. The large quantity of the light curing resin 12 applied to the cutout 11 is gradually caused to flow into the ventilation hole 15 due to its fluidity over time, and is hardened while the ventilation hole 15 is kept closed. Since the ventilation hole 15 is not kept opened, the solid-state imaging device 1 has no malfunction due to the entering of minute dust, etc. into the inside of the cover glass 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hermetic sealing method for a solid-state imaging device, in which the solid-state imaging device is hermetically sealed with a transparent cover plate.

  Digital cameras, video cameras, and the like that use solid-state imaging devices such as CCDs and CMOS sensors are in widespread use. In this solid-state imaging device, a semiconductor substrate on which a solid-state imaging element is formed is die-bonded to a package substrate made of ceramic or the like, and after electrically connecting the semiconductor substrate and the electrode of the package substrate using a bonding wire, A glass cover made of transparent glass is attached to the package substrate from above so as to be sealed.

Such a sealing structure has a problem in that the cover glass is peeled off due to an increase in pressure inside the cover glass by heating when the cover glass is bonded to the bonding surface on the package substrate side by a resin in the manufacturing process. On the other hand, for example, Patent Document 1 proposes a semiconductor manufacturing method in which peeling is prevented by providing grooves in at least two locations of the frame and ventilating the inside of the cover glass. Although similar to the above-described sealing structure, as a similar hermetic sealing method, an internal pressure is provided so that gas is released from the inside during sealing by providing a gap in advance in a sealing material formed of Au-Sn solder. A semiconductor package for preventing leakage failure due to the above has been proposed in Patent Document 2.
Japanese Patent Laid-Open No. 06-132413 JP 2004-119881 A

  However, in the hermetic sealing method described in Patent Document 1, since the gap due to the groove remains open, the hermeticity is lost, and minute dust enters the space inside the cover glass. In this case, there is a problem that a semiconductor element such as a solid-state image sensor causes a malfunction.

  Moreover, since the hermetic sealing method described in Patent Document 2 is a method using a sealing material formed of Au—Sn solder, it cannot be applied to hermetic sealing using a resin as the sealing material.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a sealing method for a solid-state imaging device that hermetically seals the solid-state imaging device with a cover glass without peeling.

  In order to solve the above-described problem, in the hermetic sealing method for a solid-state imaging device according to the present invention, the solid-state imaging device mounted on a package substrate has an opening facing the light receiving area of the solid-state imaging device, When a transparent cover plate is bonded from above to a frame-shaped side wall portion integrally formed with the package substrate so as to surround the side surface of the solid-state imaging device, one or more end portions of the cover plate are attached to the end portion of the cover plate. While securing a vent hole for ventilating the inside of the cover plate by providing a notch, a larger amount of photocurable resin is applied to the upper surface of the side wall portion corresponding to the position of the notch than the other upper surface, While the cover plate is bonded to the side wall and irradiated with light, the photo-curing resin applied to the other upper surface is cured prior to the large amount of photo-curing resin, while the front The large amount of the photocurable resin so as to bond the cover plate to the side wall by being cured by closing the vent over time.

  In the hermetic sealing method of the solid-state imaging device, the photocurable resin may be an ultraviolet curable resin, and the light may be an ultraviolet ray.

  By using the hermetic sealing method of the solid-state imaging device, the ventilation holes inside the cover glass formed by the cutout of a large amount of the resin curable oil applied to the position of the cutout provided in the coverglass over time. Since it gradually closes and hardens more slowly than the photo-curing resin applied to other parts, it is possible to ventilate the inside of the cover glass until the vent hole is closed. Since no atmospheric pressure difference occurs, the solid-state imaging device can be hermetically sealed without causing the cover glass to peel off. As a result, the yield is greatly improved in the manufacture of the solid-state imaging device.

  If the hermetic sealing method of the solid-state imaging device is used for an ultraviolet effect resin often used in the production of a solid-state imaging device, the above effect is further improved.

  FIG. 1 shows an example of a cover glass used for sealing in a hermetic sealing method for a solid-state imaging device according to the present invention. FIG. 2 shows a solid-state imaging device manufactured using this cover glass. The cover glass 5 is a thin rectangular plate glass, and a substantially U-shaped notch 11 is provided at the center of the short side end. This notch 11 is for securing a ventilation hole for ventilating the inside of the cover glass 5 when the solid-state imaging device 2 is hermetically sealed as will be described later. In addition, when providing the notch 11, if the ventilation can fully be performed, there will be no restriction | limiting in the position on the cover glass 5, and a number.

  The cover glass 5 is made of low α-ray glass. The low α-ray glass is a glass that emits less α rays and prevents the light receiving elements of the solid-state imaging device 2 from being broken by α rays. Note that an infrared cut filter or an optical low-pass filter may be bonded to the upper surface of the cover glass 5.

  The solid-state imaging device 1 includes a rectangular plate-shaped solid-state imaging device 2, a cover glass 5 that covers a light receiving area 6 of the solid-state imaging device 2, and a package substrate 3 that holds the cover glass 5 and seals the solid-state imaging device 2. And have.

  The light receiving area 6 of the solid-state imaging device 2 is formed by a large number of microlenses 10 arranged in a matrix at the center of the upper surface, and RGB color filters and light receiving elements formed under each microlens 10. The charge accumulated in these light receiving elements is transported by a charge coupled device (CCD). In addition, external terminals 8 are arranged along the short side on the upper surface of the solid-state imaging device 2, and are electrically connected by an internal electrode 7 and a bonding wire 9 to be described later to transmit and receive signals. As the solid-state imaging device 2, a CMOS sensor or the like can be used instead of the CCD.

  The upper surface of the package substrate 3 is a bonding surface to which the solid-state imaging device 2 is bonded, and a side wall portion 4 rising from the upper surface is integrally formed with the package substrate 3 around the bonded solid-state imaging device 2. . The side wall portion 4 is constituted by a wall that surrounds the side surface of the solid-state imaging device 2 from four directions, and has a frame shape that opens upward facing the light receiving area 6. Although ceramic is used as the material of the package substrate 3 and the side wall portion 4, the material is not limited to this, and plastic may be used, for example. Further, the side wall portion 4 facing the arrangement of the external terminals 8 is formed in a step shape, and the same number of internal electrodes 7 as the external terminals 8 are arranged on the first flat portion 14 of the side wall portion. The internal electrode 7 is connected to a conductive wiring (not shown) provided on the package substrate 3. The other end side of the conductive wiring is a lead portion (not shown) exposed to the outside of the package substrate 3. This internal electrode is connected to the external terminal 8 of the solid-state imaging device 2 via a bonding wire 9.

  The solid-state imaging device 2 is bonded to the bonding surface of the package substrate 3 with an adhesive, and a thermosetting adhesive is used as the adhesive. As the adhesive, a type other than the thermosetting adhesive may be used.

  The cover glass 5 is bonded to the upper surface 13 of the side wall 4 of the package substrate 3 with a photocurable resin 12 applied. The photocurable resin 12 is a synthetic organic material that changes from liquid to solid by the action of light energy and cures when irradiated with light. The photo-curing resin 12 is generally an ultraviolet-curing resin (UV-curing resin) that is cured with ultraviolet rays, but visible light curing that is cured with visible light that is safer and more transmissive than human ultraviolet rays. A resin may be used.

  As will be described later, a large amount of photocurable resin 12 is cured on the upper surface 13 corresponding to the position of the notch 11 in order to close the air hole secured by the notch 11 provided in the cover glass 5. Therefore, the airtightness in the cover glass 5 is maintained. Such a solid-state imaging device 2 is used by being attached to a lens barrel in which a photographing lens is incorporated.

  Next, FIG. 3 shows a top view of the solid-state imaging device 1, and FIG. 4 shows a cross-sectional view along X shown in FIG. 3 to show a hermetic sealing method for a solid-state imaging device according to the present invention. explain. 3 and 4, (a) shows a state before the photocurable resin 12 is cured, while (b) shows a state after the curing.

  As shown to (a) of FIG. 3 and 4, the manufacturing apparatus of the solid-state image sensor 1 bonds the cover glass 5 on the upper surface 13 of the side wall part 4 to which the photocurable resin 12 was apply | coated. Here, a small amount of the photo-curing resin 12 is thinly applied to the upper surface 13 of the side wall portion 4 so that the cover glass 5 can be sufficiently adhered. On the other hand, the notch 11 provided in the cover glass 5 The photocurable resin 12 gradually flows into the vent hole 15 over time due to fluidity at the location of the upper surface 4 corresponding to the position, and a small amount of the photocurable resin 12 applied to the location of the other upper surface 13 is cured. After that, a large amount of photo-curable resin 12 that is necessary and sufficient to be cured in a state in which the vent hole 15 is closed is applied.

  When light is irradiated by the light irradiation device in a state where the cover glass 5 is bonded to the upper surface 13 of the side wall portion 4, first, a small amount of the photocurable resin 12 applied to the upper surface 13 other than the location of the notch 11 is cured. At this time, the photo-curing resin 12 applied to the notch 11 is not cured yet because of its large amount, and the ventilation hole 15 is secured, so that the inside of the cover glass 5 is ventilated. be able to. Accordingly, there is no pressure difference between the inside and outside, so that the cover glass 5 does not peel off.

  As shown in FIGS. 3 and 4 (b), a large amount of the photo-curable resin 12 applied to the notch 11 portion gradually flows into the vent hole 15 due to fluidity as time elapses. Hardens while plugged. As a result, the vent hole 15 does not remain open, so that fine dust or the like enters the cover glass 5 so that the solid-state imaging device 1 does not malfunction.

  In the present embodiment, the notch provided in the cover glass is not limited to the shape as shown in FIG. 1, and for example, as shown in FIG. 17 may be sufficient. Moreover, in this embodiment, you may use the thermosetting resin hardened | cured by heat irradiation instead of a photocurable resin.

It is a perspective view which shows an example of the cover glass which airtightly seals the solid-state image sensor of this invention. It is an example of the solid-state imaging device completed by applying the cover glass. It is a top view of the solid-state imaging device. It is sectional drawing of the said solid-state imaging device. It is a perspective view which shows another example of the cover glass which airtightly seals the solid-state image sensor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid-state imaging device 2 Solid-state image sensor 3 Package board 4 Side wall part 5,16 Cover glass 6 Light-receiving area 7 Internal electrode 8 External terminal 9 Bonding wire 10 Microlens 11,17 Notch 12 Photocurable resin 13 Upper surface 14 Plane part 15 Vent

Claims (2)

A frame-shaped side wall formed integrally with the package substrate so that the solid-state image pickup device mounted on the package substrate has an opening facing the light receiving area of the solid-state image pickup device and surrounds the side surface of the solid-state image pickup device In a hermetic sealing method of a solid-state imaging device that hermetically seals by adhering a transparent cover plate to the part from above with a photocurable resin,
By providing at least one notch at the end of the cover plate, a vent hole for ventilating the inside of the cover plate is secured, and the upper surface of the side wall corresponding to the position of the notch is more than the other upper surface. A large amount of photocurable resin is applied, and the cover plate is bonded to the side wall portion and irradiated with light so that the photocurable resin applied to the other upper surface is cured prior to the large amount of photocurable resin. On the other hand, the solid-state image pickup device is hermetically sealed by adhering the cover plate to the side wall portion by closing the vent hole and curing the large amount of the photocurable resin over time. 2. The hermetic sealing method for a solid-state imaging device according to claim 1, wherein the photo-curable resin is an ultraviolet curable resin, and the light is an ultraviolet ray.

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