JP2574559B2 - Image sensor manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a one-dimensional image sensor for converting an optical image into an electric signal.

[0002]

2. Description of the Related Art Conventionally, in order to mount a semiconductor element such as an image sensor on a bare chip, a light-curable insulating resin is applied to a light-transmitting substrate 30 such as a film having a circuit conductor layer 34 formed on the surface in FIG. An image sensor is produced by mounting a semiconductor image sensor element 31 having a light receiving element 32 through a face 33 such that an extraction electrode 35 formed on the element comes into contact with the circuit conductor layer 34 face down. I was

[0003]

However, with the above-described configuration, the contact resistance of the electrode that has come into contact in tests under various environments often becomes abnormally high. This is because there is no resin to be bonded between the abutting electrodes, and the light-transmitting substrate, such as a film, having a significantly different coefficient of thermal expansion from the semiconductor image sensor element cannot maintain the pressure contact force between the electrodes.

[0004]

According to a method of manufacturing an image sensor of the present invention, a circuit conductor layer formed on a surface of a light-transmitting substrate and an electrode formed on a surface of a semiconductor image sensor element having a light receiving element are provided. In a method of manufacturing an image sensor to be mounted using a light-transmitting light-curable insulating resin, a step of applying a conductive adhesive on a circuit conductor layer formed on the surface of the light-transmitting substrate; A step of temporarily solidifying an agent; a step of applying the translucent photocurable insulating resin to the translucent substrate surface; and an electrode and a conductive adhesive formed on the semiconductor image sensor element surface are applied. The method includes a step of pressure-contacting the circuit conductor layer, a step of curing the light-transmitting light-curable insulating resin, and a step of fully curing the conductive adhesive by heating.

Further, a circuit conductor layer formed on the surface of the light-transmitting substrate and an electrode formed on the surface of the semiconductor image sensor element having the light-receiving element are mounted using a light-transmitting light-curing insulating resin. In the method of manufacturing an image sensor,
A step of forming a solder layer on a circuit conductor layer formed on the surface of the light-transmitting substrate, a step of applying the light-transmitting light-curable insulating resin on the surface of the light-transmitting substrate, and the semiconductor image sensor element A step of curing the translucent photo-curable insulating resin while pressing the electrode formed on the surface and the circuit conductor layer on which the solder layer is formed; and a step of melting the solder layer by heating.

[0006]

According to the present invention, an electrode formed on a semiconductor image sensor element and a circuit on a light-transmitting substrate are maintained while maintaining excellent mounting accuracy by being cured by a photocurable insulating resin by the above-described process. It is an object of the present invention to provide a manufacturing method for improving the electrical bonding with a conductor layer and improving the reliability of a semiconductor device.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the drawings by taking an example of an image sensor.

FIGS. 1A and 1B are a cross-sectional view and a schematic process diagram of an image sensor according to a first embodiment of the present invention. 11 is a light-transmitting substrate, 12 is a circuit conductor layer formed on the surface of the light-transmitting substrate 11, 13 is an image sensor element used as a semiconductor element, 14 is an electrode provided on the image sensor element 13, 15 Is a transparent light-curable insulating resin for mounting the semiconductor image sensor element 13 on the translucent substrate 11, 16 is a conductive adhesive, and 17 is a light receiving element provided in the semiconductor image sensor element 13.

A method for manufacturing the image sensor having the above-described configuration will be described. First, a light receiving element 17 such as a phototransistor or a photodiode is mounted on a single crystal silicon substrate (wafer) using a semiconductor process.
And an access circuit (not shown) such as a MOS, a bipolar IC or the like is provided. For each electrode 14, Au
20 to 50 formed using a wire bonder process
The bump structure protrudes from the wafer surface by about μm. Thereafter, the wafer is cut by a high-precision dicing technique to produce a semiconductor image sensor element 13. Next, a metal such as copper is deposited on a light-transmitting substrate 11 such as polyarylate (PA), polyethersulfone (PES), or polyethylene terephthalate (PET) having a thickness of about 50 μm by vapor deposition or sputtering. Alternatively, the circuit conductor layer 12 is formed using a foil or the like, and the circuit conductor layer 12 is formed later by a photolithography method. The conductive adhesive 16 is applied to the position where the circuit conductor layer 12 and the electrode 14 are in contact with each other by a screen printing method or the like.
The conductive adhesive 16 is applied in an island shape to a thickness of about 20 μm.
Is preliminarily solidified (cured) by raising the temperature to a temperature at which it is not completely cured. Next, a predetermined amount of an acrylate-based transparent photocurable insulating resin 15 is applied to a predetermined position of such a light-transmitting substrate 11 by a stamping method, a screen printing method, or the like, and the semiconductor image sensor element 13 is placed thereon. 14 is arranged face down so as to abut on the predetermined circuit conductor layer 12 from above the conductive adhesive. Thereafter, while applying pressure from above the semiconductor image sensor element 13, the transparent photocurable insulating resin 15 is irradiated with ultraviolet rays through the translucent substrate 11 to be cured. At this time, it is desirable that the electrode 14 and the circuit conductor layer 12 are in direct contact with each other, but this is not always necessary because the conductive adhesive 16 is interposed therebetween. Next, the temperature is raised to a temperature at which the conductive adhesive 16 is completely cured, and the mounting is completed.

At this time, if the photo-curable insulating resin 15 is made of a photo-thermo-setting insulating resin, the heat resistance is excellent, and the uncured portion is cured by being shielded from light by the conductive layer, so that the reliability is further improved.

In this image sensor, light information is detected by a light receiving element 17 through a light transmitting substrate 11 and a transparent light curing type insulating resin 15 and is converted into an electric signal. Using this sensor, a perfect contact image sensor can be formed by directly contacting the original with the translucent substrate.

As the transparent photocurable insulating resin 15, a urethane acrylate or epoxy acrylate ultraviolet curable resin is preferable from the viewpoint of adhesiveness and photosensitivity.

When an image sensor having the structure shown in FIG. 1 is manufactured, a polyarylate film is used for the light-transmitting substrate 11,
Further, a copper foil was adhered thereon using a transparent adhesive, and the copper foil was processed by a photolithography method to obtain a circuit conductor layer.

On the surface of the polyarylate film, 0.1%
By providing irregularities of 2 μm to 2.0 μm, the adhesiveness to the transparent photocurable insulating resin 15 is improved, and high temperature and high humidity (8
5 ° C, 85%), high temperature (85 ° C), low temperature (-40 ° C), and various kinds of tests such as thermal shock (-40 ° C to + 85 ° C) are possible, and the reliability as an image sensor is increased. And improved practical use.

An example using a solder layer as a manufacturing method of the second embodiment of the present invention will be described. Similar to the above embodiment, the manufacturing method will be described by taking the image sensor of FIGS. 2A and 2B as an example.

First, a semiconductor light-receiving element 27 and an access circuit (not shown) such as a bipolar IC are provided on a single-crystal silicon substrate (wafer) using a semiconductor process. For each electrode 24, Au
20 to 50 formed using a wire bonder process
The bump structure protrudes from the wafer surface by about μm. Thereafter, the wafer is cut by a high-precision dicing technique, and the semiconductor image sensor element 23 is manufactured. Next, a metal such as copper is formed on a translucent substrate 21 such as polyethersulfone (PES) or polyetheretherketone (PEEK) by an evaporation method, a sputtering method, or the like, and a circuit is formed by a photolithography method later. The conductor layer 22 is formed. At a position where the circuit conductor layer 22 and the electrode 24 are in contact with each other, a low-temperature melting solder layer 26 is formed by plating to a thickness of 3 to 20 μm.
It is formed to a thickness of about. Next, such a translucent substrate 21
A predetermined amount of a transparent photo-curable insulating resin 25 is applied as a acrylate-based photo-thermo-curable non-solvent insulating adhesive by a stamping method, a screen printing method, or the like, and a semiconductor image sensor element is formed thereon. 23 is arranged face-down such that the electrode 24 contacts the predetermined circuit conductor layer 22 from above the low-temperature melting solder layer 26. Thereafter, while applying pressure from above the semiconductor image sensor element 23,
The photothermosetting insulating adhesive 25 is cured by light irradiation. Thereafter, the temperature is raised to 150 ° C. to melt the low-temperature molten solder layer 26 and solder the circuit conductor layer and the electrode 24.

The image sensor thus obtained has a high temperature and high humidity (60 ° C., 90%), a high temperature (70 ° C.), a low temperature (−30 ° C.), a thermal shock (−30 ° C. to + 70 ° C.), and the like. It made it possible to withstand various tests, improved the reliability as an image sensor, and made it practical.

Further, since the semiconductor image sensor element 23 is fixed by light curing, the semiconductor image sensor element 23 can be mounted with high positional accuracy, and can be applied to a high-density image sensor without displacement due to heating.

[0019]

As described above, according to the manufacturing method of the present invention, a semiconductor image sensor device is mounted on a light-transmitting substrate provided with a circuit conductor layer in a so-called face-down manner with high reliability.
Since it can be mounted with high accuracy, it is possible to realize a complete contact type image sensor using Si crystal,
An inexpensive and highly reliable image sensor can be provided, and it can be easily adapted to a high-density image sensor.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of an image sensor manufactured by a manufacturing method according to a first embodiment of the present invention. FIG. 1B is a schematic view of a manufacturing process according to the first embodiment of the present invention.

2A is a cross-sectional view of an image sensor manufactured by a manufacturing method according to a second embodiment of the present invention; FIG. 2B is a schematic view of a manufacturing process according to the second embodiment of the present invention;

FIG. 3 is a cross-sectional view of a conventional image sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Translucent board 12 Circuit conductor layer 13 Semiconductor image sensor element 14 Electrode 15 Transparent photocurable insulating resin 16 Conductive adhesive 17 Light receiving element 21 Translucent substrate 22 Circuit conductor layer 23 Semiconductor image sensor element 24 Electrode 25 Transparent light Curable insulating resin 26 Low temperature melting solder layer 27 Light receiving element

Claims (2)

(57) [Claims] 1. A circuit conductor layer formed on a surface of a light-transmitting substrate and electrodes formed on a surface of a semiconductor image sensor element having a light-receiving element are mounted using a light-transmitting light-curing insulating resin. In the method for manufacturing an image sensor, a step of applying a conductive adhesive on a circuit conductor layer formed on the surface of the light-transmitting substrate; a step of temporarily solidifying the conductive adhesive; Applying the translucent photo-curable insulating resin to a surface; pressing an electrode formed on the surface of the semiconductor image sensor element with a circuit conductor layer to which a conductive adhesive is applied; A method for manufacturing an image sensor, comprising: a step of curing a conductive photocurable insulating resin; and a step of fully curing a conductive adhesive by heating. 2. A circuit conductor layer formed on a surface of a light-transmitting substrate and an electrode formed on a surface of a semiconductor image sensor element having a light-receiving element are mounted using a light-transmitting light-curing insulating resin. Forming a solder layer on a circuit conductor layer formed on the light-transmitting substrate surface, and applying the light-transmitting light-curable insulating resin to the light-transmitting substrate surface. Curing the translucent light-curable insulating resin while pressing the electrode formed on the surface of the semiconductor image sensor element and the circuit conductor layer on which the solder layer is formed, and heating the solder layer. A method for manufacturing an image sensor, comprising: