JPS59228758A - Image sensor - Google Patents

Abstract

PURPOSE:To obtain an excellent moisture resistance and temperature resistance impact strength by covering the main surface of a substrate with polyimide resin, and covering the wiring unit with Si resin. CONSTITUTION:After a large-sized image sensor substrate is cleaned by ultrasonic wave, and polyimide regin having photosensitivity is covered on the overall surface. Then, a pattern is formed to cover a wiring unit 5 for wiring a multilayer and all polyimide resin portion except the hatched part of the lead leading part 6 of a common side electrode, and heat treated. Then, it is bonded to the part 5 with a film lead 7, and a multilayer wiring unit 8 is formed, which is covered with Si resin. Since the polyimide resin is cured at relatively low temperature after coated on the unti 8, the unit 8 is not deteriorated. Since the Si resin has extremely small moisture absorption rate as compared with the polyimide regin, the resistivity does not decrease even if allowed to stand for a long period in a high moisture atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image sensor requiring multilayer wiring.

Conventional structure and problems Conventionally, for example, as an image sensor used in a card reader, etc., a double optical sensor array is placed inside a case, first coated with silicone resin, and then epoxy resin is poured in to form a protective film. There is something that says. There are also types in which the photoconductive cell is coated with a silicone resin by spraying or dipping to protect it.

However, silicone-based resins have the disadvantage of poor adhesion, and good adhesion cannot be obtained unless the coating surface is highly clean6.
In addition, silicone resin has a high moisture permeability, so bubbles and pinholes are not a problem, and it can be used as a finely molded optical sensor on a large-area substrate, such as a large image sensor used in facsimile machines. However, it has been difficult to obtain a uniform protective film without bubbles or pinholes. Furthermore, silicone resins have the disadvantage that they are soft even after curing and are easily scratched.

In order to prevent these drawbacks of silicone resin, the optical sensor array used in the card reader is further coated with an epoxy resin, but due to the thickness of the epoxy resin, temperature cycling may be difficult.゛Due to testing, cracks may occur. Also, if a large-area substrate, such as the large image sensor used in facsimiles, is coated with epoxy resin,
Expansion and contraction of the epoxy resin due to temperature changes may cause the optical sensor array substrate to warp and even crack.

A large image sensor used in facsimiles, etc., which is coated with silicon face, which is a typical type of silicone-based resin that has these drawbacks using a dipping method, and has multilayer wiring, was subjected to a moisture resistance test, which is one of the reliability tests. , for example 60℃,
When left in an atmosphere of 90% RH for 2 hours, the resistance value of the optical sensor will decrease and increase.
Variations occurred in the resistance value of the optical sensor array. This is due to poor adhesion between the optical sensor array and the silicone face, or air bubbles or pinholes near the optical sensor, and moisture enters through the air bubbles or pinholes and condenses on the optical sensor. The resistance value of the optical sensor increases or decreases depending on the condition.

Also, a show I- occurred in the wiring section of the optical sensor array, and it no longer showed a normal resistance value. This occurs when the above-mentioned defective part exists in the multilayer wiring part, and moisture condenses between the wirings, causing a leakage current to flow, which has a negative effect on the resistance value of all optical sensors due to the matrix connection. This is due to the fact that it was given.

Another large image sensor was coated with silicone resin by dipping and then coated with Hysol, an epoxy resin, at 60°C and 90°C.
When left in a similar atmosphere, the aforementioned resistance value of the optical sensor increased and decreased, and the optical sensor array was damaged. Furthermore, this sample was subjected to one of the reliability tests.
As a result of a temperature cycle test at ℃, a crank appeared on the coated surface.

In this way, conventional image sensors have achieved sufficient reliability, especially in terms of moisture resistance and temperature shock, for optical sensor arrays on large-area substrates, such as large image sensors used in facsimile machines. It was difficult to obtain.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional drawbacks and to provide a large-sized image sensor for use in facsimiles, etc., which is especially effective against moisture resistance and temperature shock. It is something.

Structure of the Invention A first image sensor of the present invention includes: (1) a part of the optical sensor and a wiring part are formed on one main surface of the base plate, and a film lead is electrically connected to the connection part of the wiring part. The entire surface of the substrate except for the wire connection portion is coated with a polyimide resin, and the wire connection portion is coated with a silicone resin.

In a second image sensor of the present invention, a part of the optical sensor and a wiring part are formed on one principal surface of a substrate, and a conductive thin film is electrically connected to the wiring part at a connection part of the wiring part. Further, the entire surface of the substrate including the connection portion is coated with polyimide resin.

Even if the image sensor bar and optical sensor array of the present invention are not very clean, they have good adhesion, very low moisture permeability, and protect the polyimide resin that has excellent defoaming properties. Since it is used for membranes, air bubbles and pinholes are not a problem, and it is possible to form Nupin coat membranes and printed membranes, and the membrane thickness can be as thin as 10 microns or less, so expansion and contraction of the membrane due to temperature changes is a problem. Since this does not occur, no cranking occurs in the coating. In addition, since it is possible to cover everything except the connection parts of the multilayer wiring section in advance,
There are advantages such as not having to be careful in handling the optical sensor array after coating.

Furthermore, CdS-Se, which is an it-■ group compound semiconductor,
In line with optical sensors formed from films, it also has the advantage of not having any harmful effects even when directly coated, as it does not contain components that can have a negative impact, such as epoxy resins. It is possible to simultaneously coat a portion of the multilayer wiring section of an optical sensor array that requires multilayer wiring, excluding the connection portion, and a portion of the optical sensor with the same resin.

The first image sensor of the present invention covers the wiring connection part with a silicone resin, and this silicone resin is easily hardened by heat treatment at a temperature that is high enough to cause deterioration of the wiring connection part. In fact, it is effective as a resin for covering the wire connection portion without deteriorating it after the wire connection portion is formed.

In addition, in the case of the second image sensor of the present invention in which multilayer wiring is formed of a conductive thin film, if solder or the like is not used for the electrical connections of the multilayer wiring, the connection parts will deteriorate even when heated to about 300 degrees Celsius. In this case, it is effective to use polyimide resin on the entire surface of the image sensor substrate including the connection portion.

Description of Examples (Example 1) Examples of the image sensor of the present invention will be described above.

FIG. 1 is a diagram for explaining an image sensor according to an embodiment of the present invention, and shows a partially enlarged perspective view of a large-sized image sensor. This image sensor is manufactured as follows. Cd5-C containing Cu as an impurity on a glass substrate 1 of 230 x 25 x 1.2 tmm.
After depositing the dSe solid solution by vapor deposition, a Cd5-3e film 2 is formed using a photoetching technique to form a microfabricated Cd5-3e film 2 with a size of 32020 microfrons x 8 microns and a density of 1728 bits/8 bits. Next, Cd S −
In order to impart photosensitivity to the Se film 2, donor impurity Ct
Heat treatment is performed in an atmosphere at 520'C for 60 minutes.

Then, the common side electrode 3 in which 32 bits of the C+1S-3e film 2 are shared in common and the individual electrodes 4 separated in 1-bit increments are connected to the
Opposing electrodes of the i Or -Au vapor deposited film are formed by a lift-off method to form a large image sensor substrate.

Next, this large image sensor substrate was immersed in acetone and subjected to ultrasonic cleaning. After that, a photothermographic polyimide resin was coated on the entire surface with a thickness of 5 to 6 microns, and a photoresist was removed. Perform the same operation as for the first
The polyimide resin is heated to imidize the polyimide resin at 30°C. Heat treatment is performed to promote this.

Next, using the film lead 7 shown in FIG. 2, bonding is performed with a low melting point metal such as solder to the connection part 5 for multilayer wiring to form a multilayer wiring part 8, which is made of silicon-based resin. It is a representative material and is coated with arsilicon varnish. Note that when the multilayer wiring section 8 is coated with a silicone resin, the silicone resin has a lower moisture absorption rate (η The resistivity does not decrease even if left as it is, and it can be used in the multilayer wiring section 8 that requires insulation.

Polyimide resin is easily cured by heat treatment at a relatively low temperature after being applied to the multilayer wiring part 8, so even when a low melting point metal such as solder is used for the multilayer wiring part 8, the polyimide resin can be easily cured by heat treatment at a relatively low temperature. will not deteriorate.

Note that all parts of the surface of the glass substrate 1 are coated with polyimide resin in advance except for the connection parts 5 for multilayer wiring, and the film leads 7 and the connection parts 5 for multilayer wiring are coated with polyimide resin in advance.
Only the bonded ink portion of the wire is exposed, but this exposed portion is the part where the wiring spacing is the largest, so it will not be a problem as long as moisture does not enter and condensation is large.

Furthermore, the individual side terminals are taken out using the individual side film leads 9 of FIG. 3, and the common side terminals are taken out using the common side film lead 10, thereby producing a large image sensor 11.

This large image sensor 11 was subjected to a humidity test, which is one of the reliability tests, for example, 35°C, 85%RH, 6
500 into the atmosphere of 0 0 CI 9 o % R H
Even if left for a long time, the conventional image sensor mentioned above
There were no problems with polyimide resin and 230X.
The adhesion to the glass substrate 1 with a size of 25 x 1.2 tmm is excellent over the entire surface, and a uniform protective film is formed without bubbles or pinholes, and the silicone resin coating the multilayer wiring section 8 is also effective. It was confirmed that it was working. Furthermore, even if this large image sensor 11 is subjected to a temperature cycle/L/test from -20°C to 80°C, which is one of the reliability tests, more than 10 times, no damage will occur with the conventional protection method described above. It was confirmed that there were no problems at all.

In this manner, it was found that the image sensor of this example is highly reliable even when used as a large image sensor used in facsimiles and the like.

(Example 2) In this example, in addition to the large-sized image sensor of Example 1, a photosensitive polyimide resin is coated with a paste-like polyimide resin that can be printed.

First, a printing mask was used to cover all parts of the large image sensor board of Example 1 except for the hatched parts of the multilayer wiring connection part 6 and the common electrode lead extraction part 6 in FIG. Then, it is coated with a 10 micron printed film of polyimide resin, and heat treated at 3-00°C to promote imidization of the polyimide resin. The subsequent steps are exactly the same as in Example 1.

For the large image sensor manufactured in this way,
As a result of conducting the same moisture resistance test and temperature cycle test as in Example 1, it was found that the image sensor of Example 2 did not have any of the problems that occurred with the conventional image sensor described above.
It was also found that the sensor is highly reliable as a large image sensor used in facsimiles and the like.

(Example 3) In this example, for the large image sensor of Example 1, a vapor-deposited film (conductive thin film) formed by a lift-off method is used instead of the film lead 7 shown in FIG. 2 for connection for multilayer wiring. part 5
An embodiment will be described in which matrix connection is performed to form a multilayer wiring section 8, and this multilayer wiring section 8 is also coated with a polyimide resin like the other parts.

A polyimide resin having the photosensitivity described in Example 1,
AZ-112A Photoresin 1-Wonupin coated all of the connecting portions 6 for multilayer wiring in FIG. 1 and the lead extraction portions 6 of the common side electrode except for the shaded areas. After forming a resin pattern that allows matrix connection using a photomask, N1Gr
-A deposited Au film is deposited, and matrix connections are formed using a lift-off method to complete the multilayer wiring section 8. Thereafter, the multilayer wiring portion 8 is coated with a diluted polyimide resin using the Nupre method, and the polyimide resin is heat-treated at 300°C. Then, the individual side film lead 9 and the common side film 1° shown in FIG. 3 are attached to fabricate a large image sensor 11.

In this case, the multilayer wiring section 8 is formed using a conductive thin film deposited by vapor deposition, and unless a low melting point metal is used, it will not deteriorate even when heat treated at about 300°C after being covered with polyimide resin. .

For the large image sensor manufactured in this way,
As a result of conducting the same moisture resistance test and temperature cycle test as in Example 1, the image sensor of Example 3 did not have any of the problems that occurred with the conventional image sensor described above.
It was also found that the sensor is highly reliable as a large image sensor used in facsimile machines and the like.

(Example 4) This example uses the printable paste-like polyimide resin described in Example 2 to form the connection portion 5 for multilayer wiring shown in FIG.
(Electrification)) Cover all parts except the shaded part of the protruding part 6 of υA with a 10 micron printed film using a printing mask to promote imidization of polyimide at 300°C. Then, using a printing mask, the printed film of the printed conductive base 1- is matrix-connected to the connection part 5 for multilayer wiring, and then heated at 150°C.
A heat treatment is performed for 0 minutes to form the multilayer wiring section 8. After that, the multilayer wiring part 8 is coated with a printed film of polyimide resin of 10 microns using the printing mask again, and
The polyimide resin is heat-treated at 0°C.

Next, the individual side film lead 9 and the common side film lead 10 shown in FIG. 3 were attached to fabricate a large-sized image sensor.

As a result of conducting the same moisture resistance test and temperature cycle test on this large image sensor as in the other embodiments, it was found that there were no problems that occurred with the conventional image sensor described above. The sensor was also found to be highly reliable as a large image sensor used in facsimiles, etc.

Effects of the Invention As described in the above embodiments, the image sensor of the present invention
Because polyimide resin is used, there are many problems with adhesion even if the cleanliness of the optical sensor array is not high, but since it has excellent antifoaming properties, air bubbles and pinholes do not become a problem.

Moreover, it is possible to form a uniform protective film on a large-area optical sensor array and is moisture resistant.

Particularly effective against temperature shock. In addition, since it does not contain any components that adversely affect the CAS-8e film, which is a ■-■ group compound semiconductor, the parts of the optical sensor array excluding the multilayer wiring connection part 5 that requires multilayer wiring. It is possible to simultaneously coat a part of the optical sensor with the same resin, and it is also possible to coat the Cd5-8e film immediately after forming the common side electrode 3 and the individual side electrode 4. It also has the advantage that no care is required when handling the sensor array.

In addition, if the multilayer wiring connections are susceptible to deterioration due to high temperature heat treatment, cover the multilayer wiring connections with a silicone resin that hardens with low temperature heat treatment, and if deterioration due to high temperature heat treatment is not a problem, Since the connection section is also covered with a polyimide resin like other parts, deterioration of the multilayer wiring connection section can be effectively prevented.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged perspective view of a large image sensor substrate according to an embodiment of the present invention during the manufacturing process, FIG. 2 is a partially enlarged perspective view of a large image sensor substrate according to an embodiment of the present invention,
FIG. 3 is a perspective view of a large image sensor according to an embodiment of the present invention. 1...Glass substrate, 2...Cd S-S
e-film, 3...Common side electrode, 4...Individual side electrode, 5...Connection part for multilayer wiring, 6...
...Common side lead extraction part, 7...Film lead for multilayer wiring, 8...Multilayer wiring part, 9.
...Individual side film lead, 10...Common side film lead, 11...Large image sensor -0

Claims (1)

[Claims] (1) A part of the optical sensor and a wiring part are formed on the whole surface of the board, and the film lead is electrically connected at the connection part of the wiring part, and the whole part of the board except for the connection part is formed. Image sensor-0 characterized in that the surface is coated with a polyimide resin and the connection portion is coated with a silicone resin.(2) A part of the optical sensor and a wiring portion are formed on the entire surface of the substrate, A conductive thin film is electrically connected to the wiring portion at a connection portion of the wiring portion, and
Image sensor-0, characterized in that the entire surface of the substrate including the connection portion is coated with polyimide resin.