JPH02268561A - Image sensor - Google Patents

Abstract

PURPOSE:To fix a sensor substrate and a supporting substrate with high positioning accuracy with a simple means and to reduce a manufacturing cost by the simplification of a manufacturing process by providing marks for position alignment at the sensor substrate and the supporting substrate. CONSTITUTION:The sensor substrate 10 on which plural photodetectors are provided and the supporting substrate 20 to support the sensor substrate 10 are provided. The marks for position alignment are provided at the sensor substrate 10 and the supporting substrate 20, respectively, and such structure that the sensor substrate 10 and the supporting substrate 20 can be fixed so as to generate such positional relation that the marks are confronted with each other is employed. The position of the sensor substrate 10 or the supporting substrate 20 is adjusted so as to set the marks at the positional relation confronting with each other. In such a way, the position alignment of both substrates can be performed with high positioning accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image sensor, and more specifically, an image sensor comprising a sensor substrate provided with a plurality of light receiving elements and a support substrate supporting the sensor substrate. image sensor
The present invention relates to an image sensor characterized by alignment means for a sensor substrate and a support substrate.

[Technology background]

Image sensors generally have a function of reading image information on a document through photoelectric conversion, and are used in various devices such as facsimile machines and scanners.

Recently, however, there has been a strong demand for downsizing and cost reduction of image sensors, which has led to demands for more compact structures and simpler manufacturing processes.

FIG. 1 shows an example of the configuration of an image sensor.

In the figure, 10 is a sensor substrate, 20 is a support substrate,
31 is a light receiving element, 32 is a printed circuit board, 33 is a driving IC, 34 is a light source, 35 is an optical lens, 36 is a cover glass, and 37 is a chassis.

On the sensor substrate 10, a large number of light receiving elements 31 and their wiring sections are provided. This sensor board 10 is fixed on a support board 20, and a printed circuit board 32 is installed adjacent to this sensor board 10. A driving IC 33 is provided on the printed circuit board 32, and the driving IC 33 and the wiring portion of the light receiving element 31 are connected by wire bonding. 38 is a wire.

The support substrate 20 is fixed to a chassis 37, and a light source 34, an optical lens 35, and a cover glass 36 are fixed to the chassis 37.

However, this image sensor is assembled as follows.

(1) Place the sensor board 10 at a predetermined position on the support board 20.
and fix both with double-sided tape and/or adhesive.

(2) The printed circuit board 32 is placed on the support substrate 20, and both are fixed with double-sided tape and/or adhesive.

(3) The driving IC 33 is connected and fixed on the printed circuit board 32 by Gui bonding.

(4) Connecting the driving IC 33 and the wiring part of the light receiving element 31 of the sensor board 10 by wire bonding,
The driving IC 33 and the printed circuit board 32 are connected by wire bonding. As a result, a sensor module M in which the sensor substrate 10, the support substrate 20, and the driving IC 33 are integrated is obtained.

(5) In the sensor module M, the end B20A of the support substrate 20 processed into a predetermined shape with high dimensional accuracy is butted against a predetermined position of the chassis 37, so that the support substrate 20 is positioned at an appropriate position relative to the chassis 37. Fixed.

In the image sensor manufactured as described above, the original passing over the cover glass 36 is irradiated by the light source 34, and the optical image of the original reaches the light receiving element 31 via the optical lens 35. The optical lens 35 is a rod lens array (made by Nippon Sheet Glass ■).

A selfoc lens) is useful, and according to this rod lens array, a 1:1 equal-magnification image is formed on the light receiving element 31.

Therefore, in order to accurately form an optical image of the document on the light receiving element 31, the light receiving element 31 on the sensor board 10 must be fixed at a predetermined position with respect to the optical lens 35 with high positional accuracy. . That is, if the light receiving element 31 is misaligned with respect to the optical lens 35, the light image of the document will not sufficiently reach the light receiving element 31, resulting in decreased sensitivity and erroneous signals.

Therefore, as a result, the sensor substrate 10 is replaced by the support substrate 20.
It is necessary to fix it with high positional accuracy.

[Problem to be solved by the invention]

However, when mass producing image sensors,
It is difficult to measure with high accuracy the positions at which a large number of sensor substrates 10 and support substrates 20 should be fixed.

Further, even if this measurement is possible, the manufacturing process becomes complicated, resulting in an increase in manufacturing costs.

The present invention has been made based on the above circumstances, and its object is to provide an image sensor having a structure that satisfies the following conditions (1) to (4).

■ The sensor board and support board can be fixed with high positional accuracy by simple means.

■ The sensor board and support board can be fixed with high reproducibility.

■ It is possible to reduce manufacturing costs by simplifying the manufacturing process.

[Means to solve the problem]

The present invention provides an image sensor comprising a sensor substrate provided with a plurality of light-receiving elements and a support substrate supporting the sensor substrate, in which alignment marks are provided in advance on each of the sensor substrate and the support substrate. and the sensor substrate is fixed to the support substrate so that these alignment marks are in a corresponding positional relationship.

[Operation] According to the present invention, alignment marks are provided in advance on each of the sensor substrate and the support substrate, and the sensor substrate is fixed to the support substrate so that these alignment marks have a corresponding positional relationship. Therefore, by adjusting the position of the sensor substrate or the support substrate so that the alignment marks have a corresponding positional relationship, it is possible to align both with high positional accuracy.

Since the positional relationship between the alignment marks can be confirmed by a simple means such as a microscope, both can be fixed with high positional accuracy without complicating the manufacturing process.

Since the alignment mark can be easily formed by using the process of forming the light receiving element, the manufacturing process does not become complicated.

Furthermore, since fixation can be performed with high reproducibility, it is suitable for mass production.

[Specific structure of the invention]

The present invention will be explained in detail below.

In the present invention, in the image sensor configured as shown in FIG. 1, alignment marks 51 and 52 are provided in advance on each of the sensor substrate 10 and the support substrate 20, as shown in FIG.

The alignment marks 51 and 52 can be provided using the remaining space of the sensor substrate 10 and the support substrate 20, respectively, and may be provided not only at one location but also at two locations at both ends, for example. In FIG. 2, 31 is a light receiving element, 31A is a common electrode, and 31C is an individual electrode.

The positional relationship between the alignment marks 51 and 52 is such that when the supporting substrate 20 is finally fixed to the chassis 37, the center of the optical lens 35 and the center of the light receiving element 31 of the sensor substrate 10 are aligned, for example. The positional relationship is set such that the positions match with a positional accuracy of within 200p.

The specific shapes of the alignment marks 51 and 52 can be changed with a considerably large degree of freedom. It is possible to adopt a method in which positioning is performed by confirming that the two shapes are different shapes and that one shape has a specific positional relationship with respect to the other shape.

A typical example of the alignment marks 51 and 52 is shown in Figure 3 (
Shown in a) to (C).

In the example shown in FIG. 3(a), one positioning mark 51 is in the shape of a cross, and the other positioning mark 52 is comprised of four blocks arranged on all sides. In this example, as shown in FIG. 4(a), the alignment mark 5
In this mode, alignment is performed after confirming that two adjacent blocks of the four blocks constituting the alignment mark 51 are in a state where the four ends of the cross shape of the alignment mark 51 are sandwiched.

In the example shown in FIG. 3(c), one alignment mark 51 has a large rectangular frame shape, and the other alignment mark 52 has a small rectangular frame shape. In this example, as shown in FIG. 4(b), the alignment mark 5
In this mode, alignment is performed after confirming that the small rectangular frame in 2 fits inside the large rectangular frame in the alignment mark 51.

In the example shown in FIG. 3(C), one alignment mark 51 consists of a chevron-shaped line, and the other alignment mark 5
2 consists of two sets of opposing blocks. In this example, as shown in FIG. 4(C), the two hem portions of the chevron-shaped line in the alignment mark 51 are
In this mode, alignment is performed after confirming that the blocks are sandwiched between a pair of blocks in each alignment mark 52.

The size of the alignment marks 51 and 52 is preferably about 200μ x 200μ at most, taking into consideration the allowable range of practical soil.

The alignment mark 51 of the sensor substrate 10 can be formed simultaneously with the wiring part using the same material as the wiring part by using the process of forming the wiring part of the light receiving element 31. In this case, the process can be simplified.

In addition, before or after forming the wiring part of the light receiving element 31, the alignment mark 5 is formed by a printing method or a resist method.
1 may be formed on the sensor substrate 10.

The alignment mark 52 on the support substrate 20 can be formed by a printing method or a resist method.

As a constituent material of the sensor substrate 10, a transparent material such as glass can be used.

As the constituent material of the support substrate 20, transparent or opaque materials such as glass, aluminum, and stainless steel can be used.

When fixing the sensor substrate 10 and the support substrate 20,
The position of the sensor substrate 10 or the support substrate 20 is adjusted so that the alignment mark 51 of the sensor substrate 10 has a positional relationship corresponding to the alignment mark 52 of the support substrate 20.

With the alignment marks 51 and 52 in the corresponding positional relationship as described above, the sensor substrate 1O and the support substrate 20 are fixed.

The light receiving element 31 used in the present invention is made of amorphous silicon, CCD, Cd5-CdSe, bipolar, C-
It may be either MOS.

〔Example〕

Next, examples of the present invention will be described, but the present invention is not limited to these embodiments.

Example 1 (Manufacture of sensor substrate) As shown in FIG.
A light receiving element 31 was formed as a laminate of a common electrode 31A made of O, a semiconductor layer 31B made of a-Si, and an individual electrode 31C made of aluminum.

When forming the individual electrodes 31C made of aluminum,
At the end of the substrate 10A where the light-receiving element 31 is not provided, an alignment mark 51 having the same form as that shown in FIG. 3(a) was formed of aluminum.

As shown in FIG. 6, this mark 51 has a vertical length A of 200 p layers, a horizontal length B of 200 p, and a line width C of 20 μm.
It is. Further, the distance from the center of the mark 51 to the end of the substrate 10A in the longitudinal direction is 2.0 m+n, and the distance E from the center of the mark 51 to the end of the substrate 10A in the width direction is 4.0 m+n.
5 mm, and the distance F from the center of the laminated portion of the individual electrode 31C and the semiconductor layer 31B to the widthwise end of the substrate 10A is 2.
．． It is Omm.

(Manufacture of Support Substrate) An alignment mark 52 having the same form as that shown in FIGS. 3 and 3 was formed using black ink on the edge of the support substrate 20 made of aluminum by screen printing.

As shown in FIG. 6, this mark 52 has a length G in one block of 100n and a distance H between blocks of 40n.
μm, the distance J from the center of the four blocks to one end 2OB in the width direction of the support substrate 200 is 2.0ml, and the distance from the center of the four blocks to the other end 2OA is 4.0+nm. The distance to the longitudinal end 20C of the support substrate 20 is 2.5 mm.

(Fixing the sensor board and support board) Using a microscope with a magnification of 100x, the alignment mark 51
and 52, the sensor substrate 10 and support substrate 20 were aligned so that these marks 51 and 52 overlapped in the state shown in FIG. 4(a), and both were adhesively fixed with double-sided tape.

(Evaluation) After fixing a large number of sensor boards and support boards as described above, measure the variation in the distance from the other end 2OA in the width direction of the support board 20 to the center of the light receiving element 31. As a result, the maximum accuracy was 100n, which was sufficient for practical use.

As shown in FIG. 1, the other end 2OA of the support substrate 20 is fixed against a predetermined position of the chassis 37, so that the light receiving element 31 is fixed from the end 2OA.
If the distance to the center of the document is constant, an optical image of the document can be accurately formed on the light receiving element 31.

Comparative Example 1 Without forming the alignment marks 51 and 52, the positions of the sensor substrate 10 and the support substrate 20 were aligned using a microscope with a magnification of 100 times, and the sensor substrate 10 and the support substrate 20 were aligned. The substrate 20 was adhesively fixed with double-sided tape.

(Evaluation) After fixing a large number of sensor boards and support boards as described above, the variation in the distance from the other end 2OA in the width direction of the support board 200 to the center of the light receiving element 31 was measured. However, the maximum value was 500 JIM, which caused a practical problem.

〔Effect of the invention〕

According to the present invention, since alignment marks are provided on the sensor substrate and the support substrate, the sensor substrate and the support substrate can be fixed with high positional accuracy by simple means, and moreover, the sensor substrate and the support substrate can be fixed with high positional accuracy. It is possible to fix with high reproducibility, and furthermore, it is possible to reduce manufacturing costs by simplifying the manufacturing process.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the entire image sensor, Fig. 2 is a schematic diagram of the sensor substrate and support substrate, and Fig. 3 (a) to (
C) is an explanatory diagram showing a specific example of alignment marks, Fig. 4 is an explanatory diagram showing a state in which alignment marks overlap, Fig. 5 is an explanatory diagram showing an example of the configuration of a light receiving element, and Fig. 6 is an explanatory diagram showing a configuration example of a light receiving element. FIG. 2 is a schematic diagram of a sensor substrate and a support substrate according to an example. 10... Sensor substrate 10A... Glass substrate 20... Support substrate 31... Light receiving element 31A... Common electrode 31B... Semiconductor layer 3
1C...Individual electrode 32...Printed circuit board 33...Drive IC 34...Light source 35...Optical lens 36...Cover glass 37...Chassis 38...Wire 41
, 42... Adhesive 51.52... Positioning mark CG"1 Figure 21-3 (b) + Figure 4 (C)

Claims (1)

[Claims] (1) In an image sensor comprising a sensor substrate provided with a plurality of light receiving elements and a support substrate supporting the sensor substrate, alignment marks are provided in advance on each of the sensor substrate and the support substrate. . An image sensor characterized in that the sensor substrate is fixed to the support substrate so that these alignment marks have a corresponding positional relationship.