JP2002033468A - Solid state image pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin solid state image pickup in which an optical system can be reduced in size reflectivity of a cap can be lowered and static charging as the cap can be prevented by sticking a low-pass filter also serving as the cap onto a solid state image pickup chip while sealing. SOLUTION: The solid state image pickup comprises a solid state image pickup chip 100, an antireflection coat 105, a TAB tape 110, a beam lead 120, bumps 130, and a low-pass filter 140 also serving as the cap. The solid state image pickup further comprises a light shield mask 150 formed on the low-pass filter, microlenses 160, a seal resin 170, a window 180 in the light shield mask, a transparent conductive film 190, an antireflection film 195, a device hole 210, a lead 220 for dropping the transparent conductive film to GND, and a conductive paste 230 for connecting the lead.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device, and more particularly, to a small-sized imaging device used for a video camera, a digital still camera, and the like.

[0002]

2. Description of the Related Art A solid-state image pickup device such as a CCD or a CMOS used for an image input device such as a video camera or a digital still camera is formed on a semiconductor substrate such as a silicon wafer and then formed with a color filter and a microlens. In a later step, it is divided into required dimensions and assembled. After the semiconductor process, the silicon wafer is formed on the wafer in the order of the color filter and the microlens using an acrylic material in the color filter and microlens forming process.

Conventionally, the chip is housed in a ceramic package or the like, electrically connected between the chip and the lead by wire bonding, and a cap of a glass substrate is bonded on the package. However, in recent years, in order to reduce the size of devices such as digital cameras, it has been desired to reduce the size and thickness of the solid-state imaging devices such as the CCD and CMOS.

[0004] Above all, TOG (published by Toshiba Electronic Imaging Society in October 1998) as disclosed in JP-A-07-099214 is known.

Further, conventionally, in the case of a single-lens type digital camera which requires a shutter due to static electricity or a single-lens type digital camera, the static electricity generated when the shutter is released, or the destruction or deterioration of the sensor element occurs. When a solid-state imaging device in the form of a ceramic package or the like is used, static electricity is sprayed or the like during product assembly to prevent static electricity.

In addition, the cap and the solid-state imaging device chip are bonded together with a gap of 100 μm or less by thinning,
In the case of a structure where the periphery is sealed, static electricity is generated by opening the shutter over the entire surface of the cap, and the distance between the charged surface and the element is short, so there is a problem that the element is broken or deteriorated. It is also conceivable to provide a transparent conductive film on the cap.

Further, in the case of a digital camera, as shown in FIG. 4, a low-pass filter is disposed in front of a package of a conventional solid-state image pickup device, so that miniaturization of the entire optical system is limited even if the package itself is miniaturized. . In particular, there has been a problem that the finder protrudes rearward from the finder that is peeped during shooting, making it difficult to peep. Therefore, it has been considered to reduce the size of the optical system by using quartz or lithium niobate as a low-pass filter for the cap disposed on the entire surface of the package.

[0008]

However, the refractive index of the transparent conductive film is as high as 1.7 to 2.0 as compared with the refractive index of glass of about 1.5, and when the cap is glass, the transparent conductive film is formed on the cap. When the film is provided, reflection at the interface between the cap and the transparent conductive film is increased, and the amount of light entering the imaging unit of the solid-state imaging device is reduced.

Further, since the material of the low-pass filter has a large refractive index of 2 to 2.3, the reflection at the interface with the air is large and the amount of light entering the imaging section of the solid-state imaging device is reduced. become.

Accordingly, the present invention provides a solid-state image pickup device chip in which a low-pass filter is attached to a solid-state image pickup device chip also as a cap.
Seal, reduce the size of the optical system, lower the reflectance of the cap,
It is an object to provide a thin solid-state imaging device capable of preventing charging of a cap.

[0011]

According to the present invention, there is provided a solid-state image sensor chip having a connection portion provided at a peripheral portion of an imaging area and a metal projection at the connection portion, and a solid-state image sensor chip. A flexible wiring board surrounding the solid-state imaging device chip and having a beam lead disposed on a side opposite to the solid-state imaging device chip, having a transparent cap for protecting the solid-state imaging device chip, and a metal protrusion on the solid-state imaging device chip. In a solid-state imaging device to which a beam lead of the flexible wiring board is connected and a seal layer surrounds an effective pixel area of a solid-state imaging device chip, the cap is a low-pass filter, and a transparent conductive film is formed on both sides or one side of the cap. Is provided.

[0012]

FIG. 1 is a plan view and a sectional view of a solid-state imaging device according to the present invention. 100 is a solid-state image sensor chip, 105 is an antireflection coat, 110 is a TAB tape,
Reference numeral 120 denotes a beam lead, 130 denotes a bump, and 140 denotes a low-pass filter, which also serves as a cap in the present embodiment. 150 is a light-shielding mask formed on a low-pass filter, 160 is a microlens, 170 is a sealing resin,
80 is a window of a light-shielding mask, 190 is a transparent conductive film, 195
Is an antireflection film, 210 is a device hole, 220 is a lead for dropping the transparent conductive film to GND, and 230 is a conductive paste for connecting the lead.

The leads in the device hole 210 are not bonded to the pads on the solid-state image sensor chip 100, but are bent when the cap 140 is bonded, and are connected to the transparent conductive film on the cap 140 with the conductive paste 230 or the like after the cap 140 is bonded. ing.

FIG. 2 shows an embodiment in which a conductive film is also provided on the image sensor chip 100 side. 300 is a transparent conductive film provided on the sensor side of the cap 140, and 310 is the cap 1
This is a conductive paste between 40 and the image sensor chip 100.

FIG. 3 is a schematic sectional view of a single-lens reflex digital camera using the solid-state imaging device of the present invention. Reference numeral 400 denotes an aperture, 410 denotes a shutter, and 420 denotes a mirror provided at a 45-degree angle in front of the shutter. The image is lifted in the direction of the arrow at the time of photographing, and light is transmitted to the solid-state imaging device side. Reference numeral 430 is a solid-state imaging device of the present invention, 440 is a pentaprism, 450 is an eyepiece lens, 460 is a photographing lens, 140 is a low-pass filter, and in the present embodiment, is a solid-state imaging device integrally formed as a cap.

The cap, which is a low-pass filter, is formed by bonding a plurality of sheets of quartz or lithium niobate with different crystal orientations.

Next, the manufacturing process of the solid-state imaging device of the present invention will be described.

First, ITO (indium tin oxide), which is a transparent conductive film having a refractive index of 2.0, is formed on both sides or one side of the low-pass filter by vapor deposition or sputtering.
A film including a plurality of transparent conductive films having different refractive indexes in descending order of refractive index is formed on the ITO film, and a SiO ₂ film is formed on the plurality of transparent conductive films having different refractive indexes.

Next, an anti-reflection film, which is usually made of glass, made of aluminum oxide, zirconia, and magnesium fluoride is used as the uppermost layer on the transparent conductive films having different refractive indices.

Next, since magnesium fluoride is hard to adhere, SiO ₂ is used to secure the adhesiveness of a light shielding film described later.
Form a film. In this case, the aluminum oxide, zirconia oxide, magnesium fluoride, and SiO ₂ films are formed in such a shape that a part of the transparent conductive film thereunder is exposed.

Next, a light-shielding mask portion is printed in a window shape on a low-pass filter serving as a cap. Although the thickness varies depending on the material, it is a resin that does not transmit ultraviolet rays when irradiated with ultraviolet rays. In the present embodiment, the thickness is formed by screen printing and a black epoxy resin is formed to a thickness of 30 μm. The window of the light-shielding mask is larger than the effective pixel area of the solid-state imaging device chip, and in the present embodiment, is set to be larger by 0.3 mm on each side of the effective pixel area.
The shape is such that a portion of the ITO film is provided outside of the effective pixel area where the ITO is exposed, and a portion where the lead or bump of the TAB is connected to the lead and the ITO portion are connected to form a static electricity.
Release via AB lead and wiring.

In the solid-state image sensor chip, stud bumps are formed on the pads, and the TAB beam leads and the bumps are connected at a single point using ultrasonic waves and heat. In this case, the leads for releasing static electricity are not connected to the pads of the chip.

Next, after connecting the beam leads, the window of the light-shielding mask formed on the cap is positioned on the chip so as to surround the effective pixel area of the chip, and the cap is moved so that the position of the cap does not move. Perform temporary positioning.

When connecting to the ITO disposed on the sensor side of the low-pass filter, a conductive paste is applied to the bump portions formed on the terminals on the chip, and a cap is placed thereon to temporarily fix the paste. On the other hand, when connecting to the ITO on the front side of the low-pass filter, the lead in the device hole 210 is not bonded to the pad on the solid-state image sensor chip at the time of placing the cap, and the lead in the device hole 210 is bent when the cap is bonded. After temporary fixation, it is placed on the transparent conductive film on the cap.

Next, while irradiating ultraviolet rays from the lower side of the cap with the cap side facing down, an epoxy resin, which is a combination of ultraviolet rays and heat, is applied to the cap around the chip with a dispenser. The applied sealant
Capillary force penetrates into the gap between the chip and the light-shielding mask formed on the cap, and the sealing agent comes out of the window of the light-shielding mask formed on the cap. When the sealing agent comes out of the window of the light-shielding mask, it is irradiated with ultraviolet rays, starts a curing reaction, increases the viscosity, and stops flowing. To suppress the fluidity of the sealant when it comes out of the window of the light-shielding mask, the results of experiments show that, depending on the reaction speed of the resin, a certain level of illuminance is required. Since the fluidity of the low molecular components is not suppressed, the sealant penetrates to the effective pixel region of the chip.

Next, after the sealing around the chip is completed,
Further, the connection portion of the TAB lead bent and mounted on the ITO film on the surface is fixed with a conductive paste, the sealing agent is stopped by ultraviolet rays at the window of the light-shielding layer of the cap, and then heated. The paste is cured at the same time. Note that it is also possible to irradiate ultraviolet rays from the back side to cure the seal portion around the chip and then perform heat curing.

Thus, the solid-state imaging device of the present invention is completed.

According to the above-described manufacturing method, the bumps, beam leads, and light-shielding mask portions serve as spacers, and a space is formed at a distance of 70 to 100 μm from the microlens formed on the upper surface of the chip to the cap.

In the case of a single-lens type digital camera requiring a shutter, a low-pass filter serving also as a cap is integrated by providing a transparent conductive film on a low-pass filter serving as a cap and discharging through a wiring of a flexible substrate. It becomes possible to make it thin. That is, the low-pass filter and the solid-state imaging device chip
In the case of a structure in which the surroundings are sealed with a cap of 0 μm or less, dust adheres to the entire surface of the low-pass filter due to static electricity, dust adheres due to static electricity generated when the shutter is opened in front of the cap, or the sensor element is broken. Or prevent deterioration.

[0030]

According to the present invention described above, TAB
(Tape Automated Bonding) A low-pass filter is also used as a cap on the solid-state image sensor chip mounted on the tape, the periphery is sealed to reduce the size of the optical system, and a transparent conductive film is provided on the low-pass filter. The refractive index of the film is 1.7 to 2.0
In the solid-state imaging device having a thin structure, a transparent conductive film is provided also as an anti-reflection film for the low-pass filter serving as the cap, and discharge is performed via the wiring of the flexible substrate. This makes it possible to remove static electricity and prevent destruction or deterioration of the element.

Further, the low-pass filter and the solid-state image sensor chip are integrated, so that further miniaturization including the optical system can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram of a solid-state imaging device in which a transparent conductive film is provided on a surface of a low-pass filter.

FIG. 2 is a diagram in which a transparent conductive film is provided on an image sensor chip side of a low-pass filter.

FIG. 3 is a schematic diagram of a cross section in which a solid-state imaging device is incorporated in a camera.

FIG. 4 is a cross-sectional view of a conventional camera.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 solid-state imaging device chip 105 anti-reflection film 110 TAB tape 120 beam lead 130 bump 140 low-pass filter 150 light-shielding mask 160 microlens 170 sealing resin 180 window of light-shielding mask 190 transparent conductive film 195 multilayer antireflection film 210 device hole 220 static electricity Lead to escape 230 Conductive paste for fixing lead 300 Transparent conductive film on sensor side 310 Conductive paste 400 Aperture 410 Shutter 420 Mirror 430 Solid-state imaging device 440 Pentaprism 450 Eyepiece lens 460 Photographing lens

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01L 23/02 H04N 5/335 V H04N 5/335 H01L 27/14 DF term (Reference) 2H049 BA05 BA42 BC14 BC21 4M118 AA08 AA10 AB01 BA10 BA14 GB01 GD01 HA02 HA24 HA27 HA31 5C024 BX01 CY48 EX22 EX23 EX25 EX51 GY01 GY31 5F044 MM03 MM13 NN10 RR18

Claims (8)

[Claims] 1. A solid-state imaging device chip having a connection portion provided at a peripheral portion of an imaging region and a metal projection at the connection portion, and a beam lead disposed on a side surrounding the solid-state imaging device chip and opposed to the solid-state imaging device chip. Flexible wiring board, and a transparent cap for protecting the solid-state imaging device chip, connecting the metal projection on the solid-state imaging device chip and the beam lead of the flexible wiring board, the solid-state imaging device chip In a solid-state imaging device in which a seal layer surrounds a periphery of an effective pixel region, the cap is a low-pass filter, and a transparent conductive film is provided on both surfaces or one surface of the cap. 2. The solid-state imaging device according to claim 1, wherein said low-pass filter is made of quartz or lithium niobate. 3. The solid-state imaging device according to claim 1, wherein a plurality of transparent films are formed on the cap, and the plurality of transparent films include the transparent conductive film. 4. The solid-state imaging device according to claim 1, wherein said plurality of transparent films are antireflection films. 5. The solid-state imaging device according to claim 1, wherein the transparent conductive film is made of indium oxide, tin oxide, zinc oxide, or a compound of the material. 6. A light-shielding mask having windows on a transparent conductive film formed on the cap, wherein the light-shielding layer is made of an insulating material. A solid-state imaging device according to any one of the above. 7. The method according to claim 1, wherein the transparent conductive film formed on the cap is grounded via a wiring on a flexible wiring board. The described solid-state imaging device. 8. The flexible wiring board has a second opening separate from the first opening surrounding the solid-state imaging device chip, and the transparent lead on the cap is formed by a beam lead formed in the second opening. The solid-state imaging device according to claim 1, wherein the solid-state imaging device is connected to a conductive film and grounded.