JPH0719896B2 - Contact image sensor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact image sensor used in an image input device such as a facsimile or a digital copying machine.

2. Description of the Related Art Contact image sensors used in image input devices such as facsimiles and digital copiers use semiconductor image sensor chips made of single crystal silicon such as CCD, MOS and bipolar IC type sensors, amorphous silicon and Some use semiconductor thin films such as CdS-Se. As shown in FIGS. 3 and 4, a contact image sensor using a conventional semiconductor image sensor chip has a desired circuit conductor layer 2 made of a noble metal such as gold or silver-platinum on the surface of a substrate 1 such as alumina or glass. CCD, MOS,
A plurality of semiconductor image sensor chips 3 made of single crystal silicon such as a bipolar IC type sensor are linearly arranged with high accuracy, and are bonded and fixed on a circuit board with an epoxy-based or cyanoacrylate-based conductive adhesive 4 and die-bonded. Rear electrode terminals of each semiconductor image sensor chip 3 and circuit conductor layer 2
Has a hermetically sealed structure in which a metal wire 5 such as gold or aluminum is connected by wire bonding, and then a cover glass 6 is covered and fixed with a sealing adhesive 7.

Problems to be Solved by the Invention However, such a contact-type image sensor has problems that it is difficult to reduce the thickness and that reliability of electrical connection against mechanical shock and reliability such as moisture resistance are poor. It was In addition, since the semiconductor image sensor chip 3 is difficult to correct, the process yield is poor and the economy is poor, and the cover glass 6 is a molded product, which is expensive and has a problem in terms of cost. The present invention solves such a problem, and provides a thin contact type image sensor which is excellent in reliability, improves the yield of assembly, and is excellent in economical efficiency.

Means for Solving the Problems In order to solve the above problems, a contact type image sensor of the present invention is configured such that a plurality of semiconductor image sensor chips are light-transmitted linearly in a face-down manner on a light-transmissive substrate having a circuit conductor layer. It has a structure in which the semiconductor image sensor chip and the circuit conductor layer are electrically connected by the TAB method after being fixed by adhesion with a conductive adhesive.

By using the structure of the present invention, it is possible to realize a low-cost contact image sensor that is structurally thin and has excellent reliability such as electrical connection and humidity resistance, and that the assembly yield is improved.

Embodiment One embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view of a contact image sensor according to an embodiment of the present invention, and FIG. 2 is a sectional view of a main part thereof. Figure 1,
In FIG. 2, 11 is a transparent substrate, and 12 is this transparent substrate 11
Is a semiconductor image sensor chip, 14 is a translucent adhesive, 15 is a polyimide film, 16 is a film lead using the polyimide film 15 as a support substrate, and 17 is a bump. Details will be described below with reference to FIGS. 1 and 2.

(Example 1) On a single crystal silicon substrate using a semiconductor process, on an electrode terminal of a semiconductor image sensor composed of an array of photodetectors such as phototransistors and photodiodes and switching elements such as MOS, CCD and bipolar ICs. Cr, Ti, Pd etc. are formed as a barrier metal on this, Cu, Au, In etc. are formed on the bump 16 by the vapor deposition method or the plating method, and high precision dicing technology is used from this single crystal silicon substrate. The semiconductor image sensor chip 13 is created by cutting. Next, a desired copper foil pattern is formed on the polyimide film 15 with a film thickness of 35 μm.
A film carrier is prepared by applying Sn plating with a film thickness of m, and the bump 17 on the electrode terminal of the semiconductor image sensor chip 13 and the film lead 16 are bonded with a tool.
0.05 ~ 2.5Kg, Heat time 1 ~ 3sec, Bonding temperature 1
Inner bonding (hereinafter abbreviated as ILB) under conditions of 00 to 500 ° C and semiconductor image sensor chip 13 and film lead
Connect 16 electrically. Then, on the translucent substrate 11 such as a glass substrate, a desired circuit conductor layer 12 is formed by a screen printing method or a thin film forming method and a photolithography method using a noble metal such as gold or silver-platinum, and further the circuit conductor layer 12 is formed. Au is formed to a thickness of 2 μm on the bonding pad portion to form a circuit board. Silicone, acrylic,
A semiconductor image in which epoxy-based UV-curing type, heat-curing type, UV-curing and heat-curing type translucent adhesive 14 is applied to a predetermined thickness by screen printing or a dispenser, and a film lead 16 is provided thereon. After arranging a plurality of sensor chips 13 in a straight line face down, the film leads 16 and the circuit conductor layer 12 are outer lead bonded by
Bonding temperature 100-500 ℃, Bonding pressure 0.05-
Connect under the conditions of 2.5Kg and heat time 1 ~ 3sec. After that, the translucent adhesive 14 is cured by irradiation with ultraviolet rays or heating, and the semiconductor image sensor chip 13 and the circuit board are bonded and fixed to form a contact image sensor.

(Example 2) As a bump material on the electrode terminals of the semiconductor image sensor chip 13 in Example 1, Pd-5% Sn solder bumps 17 were used.
The contact type image sensor is configured by making close contact with the film lead 16 by using, and electrically connecting by heating.

(Third Embodiment) A bump 17 between the electrode terminal of the semiconductor image sensor chip 13 and the film lead 16 in the first embodiment is formed on the film lead 16 by the transfer bump method to form a contact image sensor.

In Examples 1 to 3 above, the translucent adhesive 14 was cured after the outer lead bonding step. However, after the semiconductor image sensor chip 13 and the circuit board are cured, adhered, and fixed, the outer lead bonding is performed. Good. For the purpose of improving reliability and preventing mechanical damage, the surface of the semiconductor image sensor chip 13 is made of epoxy type or silicone type,
Molding with an acrylic adhesive is effective.

EFFECTS OF THE INVENTION As described above, according to the present invention, a plurality of semiconductor image sensor chips are linearly bonded face-down with a translucent adhesive and fixed on a translucent substrate provided with a circuit conductor layer. Since the image sensor chip and the circuit conductor layer are electrically connected by the film lead, the cover glass is eliminated and the material cost is reduced. Further, since the semiconductor image sensor chip is molded with a translucent adhesive or resin, it is resistant to mechanical vibration, and reliability such as electrical connection and moisture resistance is improved. Furthermore, since the semiconductor image sensor chip can be easily repaired because it can be electrically checked before the translucent adhesive is cured, there is an effect that the assembly yield is improved and the semiconductor image sensor chip can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view of a contact image sensor according to an embodiment of the present invention, FIG. 2 is a sectional view thereof, FIG. 3 is a perspective view of a conventional contact image sensor, and FIG. 4 is a sectional view thereof. 11 ... Transparent substrate, 12 ... Circuit conductor layer, 13 ... Semiconductor image sensor chip, 14 ... Transparent adhesive, 15 ... Polyimide film, 16 ... Film lead, 17 ... Bump.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H04N 1/028 Z 8721-5C 7210-4M H01L 27/14 D

Claims (2)

[Claims] 1. A plurality of semiconductor image sensor chips are bonded face-down on a light-transmitting substrate having a circuit conductor layer in a straight line with a light-transmitting adhesive, and the semiconductor image sensor chip and the circuit conductor layer are formed into a film. A contact image sensor that is electrically connected by leads. 2. The contact image sensor according to claim 1, wherein the surface of the semiconductor image sensor chip is molded with resin.