JPS63273353A - Solid-state image sensing device - Google Patents

Abstract

PURPOSE:To improve moisture resistance by providing an inorganic insulating film as a protective film, and further covering only the cut section and wire bonding unit of a solid state image sensing device with a molding agent. CONSTITUTION:A shift register, an analog switch 13 and a photodetector 14 made of amorphous Si are formed through a light transmissible insulating substrate 15 on a glass substrate 10, and an inorganic thin film 17 is formed as a protective film thereon. Only the cut section and wire bonding unit of this solid state image sensor are covered with a molding agent 12. According to this configuration, since the passivation layer on the top of the sensor is only with the film 17, its moisture transmittivity is extremely small. Since the film 17 itself has a very small water content rate, its moisture resistance is excellent. The top of the photodetector is not covered with the agent 12 and only the cut section and wire bonding unit of a sensor chip are covered with the agent to prevent a ghost at the time of an image for optically preventing a stray light and to obtain excellent moisture resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a puff/layer structure of a solid-state imaging device.

[Summary of the invention]

The present invention provides a solid-state imaging device formed on a light-transmitting insulating substrate, in which an inorganic insulating film is provided on the top as a protection film, and only the cut cross section and wire bonding portion of the solid-state imaging device are covered with a molding agent. This provides a solid-state imaging device with excellent moisture resistance or environmental resistance.

[Conventional technology]

The solid-state imaging device using conventional thin film transistors is the 16th
Proceedings of Rotational Body Elements and Materials Reference (Ex
tendccl Abstractsor th
e Loth Conference 5o
lid 5tate Devices and
Materials, Kobc, 1984, pp.
, 559-502), a bassibation/layer was provided on the top of the solid-state imaging device.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional technology, it is common to form only one layer of the badge vane 9F layer using a perforator-based resin.The perforator-based resin is generally made of an inorganic material. Compared to thin films (eg, silicon dioxide), improved moisture resistance cannot be expected.For example, failures such as corrosion of aluminum wiring and increased dark current may occur.

On the other hand, a method of completely molding with silicone resin or evoquine resin after wire body/digging may be considered, but these molding agents have significantly higher moisture permeability and are not expected to improve moisture resistance. Can not.

The present invention is intended to solve these problems, and its purpose is to provide a solid-state imaging device with high moisture resistance and reliability.

[Means for solving problems]

The solid-state imaging device of the present invention includes a photodetecting element made of amorphous silicon formed on a transparent insulating substrate, and a thin film transistor for driving the photodetecting element. [Function] The above-described aspect of the present invention is characterized in that an inorganic insulating film is provided as an inorganic insulating film, and in the molding agent covering the solid-state imaging device, only the cut cross section and the wire bonding portion of the solid-state imaging device are covered with the molding agent. The effect of the passivation structure will be described below based on the formation of (1).

Amorphous silicon/(
Hereinafter, a-si-II and Kizu) are used. Therefore, with the formation of a S 1 11, defects due to abnormal growth always occur in a part of the sensor. If moisture enters the defect caused by this abnormal 'Jδ' growth, a failure with a large dark current will occur.

According to 11 above, the passivation layer on the top of the sensor is only an inorganic thin film, so 1. Moisture permeability is extremely low. In addition, the inorganic thin film itself is
It has very low moisture content, so it has excellent moisture resistance. Also,
Regarding the molding agent, in order to prevent stray light due to the cross section 9 of the sensor chip cut section, the sensor chip should be molded with a refractive index of 1.
．． Must be coated with a molding agent greater than 51. However, since the molding agent is a perforation type, it has high moisture permeability and high moisture content. When this molding agent is coated on the light-receiving element, moisture is less likely to enter defects caused by abnormal growth accompanied by a-3i-II shadow formation. Moreover, since the moisture content of the molding agent is high, once the moisture enters the light receiving element, it is difficult to be released to the outside of the light receiving element, resulting in a failure with a large dark current. By making the protective film of the light receiving element inorganic, and by not covering the upper part of the light receiving element with molding agent, but only covering the cut section of the sensor chip and the wire bonding part, an image that optically prevents stray light is created. It was possible to prevent ghosting and obtain excellent moisture resistance.

〔Example〕

FIG. 1 is a structural sectional view in an embodiment of the present invention,
3A shows the vicinity of a thin film transistor and a light-receiving element, and FIG. 1B is a cross-sectional view showing a mounting section of a sensor chip. Here, an example will be described in which a polycrystalline silicon thin film transistor and an a-3t-11 (hydrogenated amorphous Si) light receiving element are used. In the same figure (a), 1 is a transparent insulating substrate, 2 is polycrystalline silicon, 3 is a gate oxide film, 4 is a gate electrode, 5 is an interlayer insulating film, 6 is an aluminum electrode, 7 is a-8t-H Light receiving element, 8 is transparent fl
It is an i-pole (ITO, etc.). 9 is an inorganic thin film. Examples of the inorganic Fg film include silicon dioxide (3101) and nitride film (Si3Na). a-3i-11
At temperatures above about 350'C, hydrogen compensating for defects is released, resulting in deterioration of photoelectricity. Therefore, SjO, and 5i
To form srlJ, it is necessary to use a low temperature (approximately 300° C. or less) formation method such as plasma CVD method or suvafuta method. Next, regarding the thickness of the passivation film, it is necessary to have a thickness of eooooλ~5 μm. A desirable film thickness is 1 μm to 3 μm. If the film thickness is less than 1 μm, it is difficult to form a step coverage film on the substrate surface, and sufficient moisture resistance cannot be obtained. If the film thickness exceeds 38 m, damage may occur and the TPT transistor A problem occurs in the characteristics.

In FIG. 1(b), 10 is a glass substrate, 11 is a mold frame, 12 is a molding agent, 13 is a shift register and an analog switch, 14 is an a-3t-II light receiving element, 17 is a transparent insulating substrate, 16 is an optical bone cement. 17 is an inorganic thin film.

The molding agent needs to have a refractive index of 1.47 to 1.56. Desirably, the refractive index is 1.52 to 1.56. When the refractive index of the molding agent is 1.47 to 1.52, 1
Since the refractive index of the light-transmitting insulating substrate No. 5 is 1.46, the refractive index of the molding agent is large, and the light directed from the light-transmitting insulating substrate No. 15 to the molding agent cuts the light-transmitting insulating substrate. Since the light travels straight without being reflected by the cross section, stray light can be prevented. However, the optical bone cement for bonding the transparent insulating substrate No. 15 and the glass substrate No. 10 has a refractive index of 1.5.
It is 1. The back side of the sensor chip is completely covered with a glass substrate.
If it is not corroded, the optical path will be blocked, so the entire surface must be corroded.

Therefore, the Bu agent is applied in a large amount, so that it protrudes to the side surfaces. The refractive index of the molding agent for the sensor chip is vc8
If the refractive index is smaller than the refractive index (1, 51) of the agent, reflection will occur at the interface, producing stray light, which will cause ghosts in images.

The solid-state imaging device thus formed was heated at 60°C90%.
Table 1 shows the results of high-temperature high-temperature tests in comparison with cases in which various types of bash basin films were entirely coated with molding agents. However, Photonice is a product name.

Table 1 However, ○... No change in photoelectric properties ×... Deterioration in photoelectric properties In either case, corrosion of the aluminum wiring did not occur, but in the conventional Badge Page 2 model shown in the comparative example, 500
While the photoelectric properties deteriorate in less than 10 hours, in all the examples according to the present invention, no change was observed in the properties even after 1000 hours or more, and it can be said that extremely high reliability was ensured.

〔Effect of the invention〕

The effects of the present invention can be described below.

<1) Since the protective film of the a-3i-1-1 (hydrogenated amorphous silicon) light-receiving element was inorganic, the light-receiving element was protected with good moisture resistance and high reliability could be obtained.

C) The method for manufacturing a protective film for a solid-state image device of the present invention simplifies the manufacturing process because only one layer of an insulating film without 11!1'f IC is formed.

(3) Since the protective film is only one layer, and the molding agent is only used for the cut section of Senzadip and the wire bonding part, the cost of raw materials can be reduced.

As described above, the present invention has the great effect of realizing a solid-state imaging device with significantly higher reliability than the conventional one. Furthermore, it is a practically useful invention because it can be applied to all kinds of electronic devices such as solid-state imaging devices using semiconductors and CdS.

[Brief explanation of the drawing]

FIG. 1(a) is a main sectional view of the solid-state imaging device of the present invention. FIG. 1(b) is a sectional view of the solid-state imaging device of the present invention. 1... Transparent substrate [Insulating substrate 2... Polycrystalline silicon 3... Gate oxidation layer 4... Gate electrode 5... Interlayer insulating film 6... Aluminum electrode 7 ・a - Si -II light receiving element 8...Transparent electrode (ITO) 9...Inorganic thin l12 (Sift) 10...Glass substrate 11...Mold frame 12...Molding agent 13...Shift register and analog switch Di14・
a-3i -I+ light receiving element 15...Transparent insulating substrate 1G...Optical adhesive 17...Inorganic thin film (SiO,) Applicant: Seiko Even/Co., Ltd. 1 Figure 1 (a) ) Figure 1(b)

Claims (1)

[Claims] (1) a light-transmitting insulating substrate; a photodetecting element made of amorphous silicon formed on the light-transmitting insulating substrate;
In a solid-state imaging device formed with a thin film transistor for driving the photodetecting element, an inorganic insulating film is provided as a protective film, and a molding agent covering the solid-state imaging device is formed with a cut cross section of the solid-state imaging device and a wire bonding portion. A solid-state imaging device characterized in that only one portion of the device is covered with a molding agent.