JPH11223532A - Integrated device and encoder using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encoder using an integrated device in which the low resistance and high reliability of wiring can be attained. SOLUTION: An optical encoder is provided with a scale 1, light source 2 for irradiating the scale 1 with a light, and light receiving integrated device 3 arranged so as to be relatively movable to the scale 1 with the light source 2 with a prescribed gap to the scale 1 for modulating and receiving a transmitted light or reflected light from the scale 1. The light receiving integrated device 3 is provided with a glass substrate 4, wiring 6 constituted by patterning the layered film of a TiSi2 film formed on the substrate 4 and an Au film formed on this, light receiving IC chip 5 loaded on the substrate 4 whose terminal is connected with the wiring 6, and SOG film 7 rotationally applied to the substrate 4 for protecting the wiring 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an integrated device in which circuit elements and wiring are formed on an insulating substrate such as glass, and an encoder using the same.

[0002]

2. Description of the Related Art An optical encoder comprises a main scale, an index scale opposed to the main scale with a predetermined gap, a light source for irradiating light to the main scale, and a light receiving element for receiving light transmitted through the index scale. It is comprised including. The main scale and the index scale are arranged so as to be relatively movable with a predetermined gap, and the light source and the light receiving element move relative to the main scale integrally with the index scale.

In such an optical encoder, a light receiving element and an index scale are integrally formed on a single glass substrate or the like as an integrated device for miniaturization and high performance. At this time, the signal wiring for taking out the output signal of the light receiving element provided on the glass substrate is LS
Aluminum (Al) is commonly used, as are other integrated devices such as I and LCD.

[0004]

However, in the above-described optical encoder, if Al wiring is formed long on a glass substrate in a fine pattern, a voltage drop due to wiring resistance cannot be ignored, and a minute output signal current of the light receiving element cannot be ignored. Is difficult to detect with good S / N. Therefore, it is desired to further reduce the wiring resistance in order to improve the performance of the optical encoder. Similar problems occur not only in optical encoders but also in various integrated devices such as LCDs and capacitive encoders, in which circuit elements are mounted on an insulating substrate such as glass.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an integrated device in which wiring on an insulating substrate is reduced in resistance and higher in reliability. It is intended to provide an encoder using a device.

[0006]

An integrated device according to the present invention is obtained by patterning a laminated film of an insulating substrate, a titanium silicide film formed on the insulating substrate, and a gold film formed thereon. And a circuit element mounted on the insulating substrate and having a terminal connected to the wiring. The insulating substrate is, for example, a glass substrate.

The present invention also provides a scale on which an optical grating is formed, a light source for irradiating the scale with light,
An optical encoder comprising: a light receiving integrated device that is disposed so as to be relatively movable with respect to the scale together with the light source with a predetermined gap with respect to the scale and modulates and receives transmitted light or reflected light from the scale. The light receiving integrated device includes an insulating substrate, wiring formed by patterning a laminated film of a titanium silicide film formed on the insulating substrate and a gold film formed thereon, and a wiring mounted on the insulating substrate. A light receiving IC having a terminal connected to the wiring. The light receiving IC is, for example, flip-chip mounted on the insulating substrate. The present invention further includes a scale in which electrodes are arranged at a predetermined pitch, and a transmission / reception integrated device in which transmission / reception electrodes are formed so as to be relatively movable with respect to the scale and capacitively coupled to the electrodes of the scale. In the capacitive encoder, the transmitting / receiving integrated device includes an insulating substrate, a transmitting / receiving electrode formed by patterning a laminated film of a titanium silicide film formed on the insulating substrate and a gold film formed thereon. It is characterized by having.

According to the present invention, titanium silicide (T
By using a laminated film of an iSi2) film and a gold (Au) film as a wiring material, a low-resistance wiring having a sheet resistance of 0.1 Ω / □ or less can be obtained. In particular, TiSi2
By interposing the film, the Au film can be formed with excellent adhesion to an insulating substrate such as glass, and a highly reliable wiring can be obtained. In addition, if the integrated device according to the present invention is applied to an optical encoder or a capacitance encoder, the light receiving I.D.
A small signal current output by C or a potential change signal due to a change in capacitance can be reliably extracted to perform signal processing with a high S / N, and thus a high-performance encoder can be obtained.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of an embodiment in which the present invention is applied to a transmission type optical encoder. This optical encoder has a scale 1 and a scale 1
And a light receiving integrated device 3 that modulates and receives light transmitted through the scale 1. The scale 1 is, for example, a transmission scale formed by forming an optical grating 11 at a predetermined pitch on a glass substrate 10. The optical grating 11 is formed by patterning a light shielding film of Cr or the like at a predetermined pitch.

The light-receiving integrated device 3 uses a glass substrate 4 as an insulating substrate and has a light-receiving IC chip 5 mounted thereon, and also serves as an index scale. That is, the light receiving IC chip 5 has a photodiode array 51 in which photodiodes are arranged and formed at a predetermined pitch and serve as an index scale. On the glass substrate 4, signal wiring 6 for extracting an output obtained from the light receiving IC chip 5
Are formed in advance. The wiring 6 has a T
This is a low-resistance wiring having a sheet resistance of 0.1 Ω / □ or less formed by patterning a laminated film of an iSi 2 film and an Au film. The light receiving IC chip 5 is mounted on the glass substrate 4 by a flip chip mounting method (face down bonding method), and terminals are connected to the wiring 6.

FIG. 2 is an enlarged plan view showing a main part of the light receiving integrated device 3 and a sectional view taken along the line AA '. FIG.
As shown in (b), the light receiving IC chip 5 has terminal pads 52 formed on the surface thereof mounted on the glass substrate 4 on which the wiring 6 is formed via solder bumps or gold bumps. On the substrate on which the light receiving IC chip 5 is mounted, a coating type insulating film formed by spin coating, that is, a spin-on-glass film (hereinafter, referred to as a spin-on-glass film).
(SOG film) 7. The SOG film 7 covers the wiring 6 and also seals a gap between the light receiving IC chip 5 and the glass substrate 4. An opening 71 is opened in the SOG film 7 at the bonding terminal portion of the wiring 6.

FIG. 3 shows a process of forming the wiring 6 using a laminated film of the TiSi2 film 61 and the Au film 62. FIG.
As shown in (a), a TiSi2 film 61 of about 200 nm is formed on a glass substrate 4 with a spatter,
An Au film 62 having a thickness of 00 nm is formed by sputtering. At this time, preferably, the Au film 6 is formed after the TiSi2 film 61 is formed.
Before the formation of No. 2, the surface of the TiSi2 film 61 is reverse-sputtered.

When the Au film 62 is formed directly on the glass substrate 4, a sufficient adhesive force cannot be obtained. However, by providing the TiSi 2 film 61 having high adhesiveness to the glass substrate 4, an excellent wiring is obtained. Adhesion is obtained. Also,
By reverse sputtering the TiSi2 film 61, the adhesion between the Au film 62 and the TiSi2 film 61 also becomes high.

Next, as shown in FIG. 3B, using the photoresist 63 as a mask, the laminated film of the Au film 62 and the TiSi 2 film 61 is etched to pattern the wiring 6. For the etching of the Au film 62, for example, I2 + KI +
Wet etching using an H2O solution or dry etching using an Ar ion beam or CCl2F2 gas plasma is used. Dry etching using the Au film 62 as a mask is used for etching the TiSi2 film 61. When dry etching gas plasma is used, Au is used as a mask with the photoresist 63 as a mask.
Continuous etching of the film 62 and the TiSi2 film 61 is also possible.

The wiring 6 is formed as described above, and the light receiving IC
After the chip 5 is mounted, next, as shown in FIG. 3C, an SOG film 7 is formed, and an opening 71 is opened in the bonding pad portion. SOG film 7 is 300 ° C. after spin coating.
Hereinafter, a low-temperature cure type SOG film that is preferably solidified by annealing at about 260 ° C. Thereby, Au
Melting and deterioration of the film 62 and the glass substrate 4 are prevented. SO
The G film 7 is a photosensitive SOG film in this embodiment. By using the photosensitive SOG film 7, it is possible to form the opening 71 by performing direct exposure without using a photoresist.

As described above, in the wiring forming process of this embodiment, sputtering and spin coating are used for film formation, and a large C
No VD device or the like is required. Further, by making the SOG film 7 of a low-temperature cure type, the total process temperature becomes about 260 ° C. at the maximum, and it is possible to obtain a highly reliable wiring by preventing deterioration after forming the laminated wiring. Further, by using a photosensitive material as the SOG film 7, the resist process can be omitted. According to this embodiment, it is possible to obtain a light receiving integrated device capable of detecting a minute current of the light receiving IC chip with a good S / N ratio by using the wiring on the glass substrate as a low resistance wiring unlike the related art. Using this, a compact and high-performance optical encoder can be obtained.

FIGS. 4A and 4B are plan views of a light-receiving integrated device 3 according to another embodiment of the present invention and its BB 'line.
FIG. In the above embodiment, the light receiving IC chip 5 is used as a circuit element for flip-chip mounting. On the other hand, in this embodiment, photodiodes 8 of amorphous silicon are arrayed directly on the glass substrate 4 to form a light receiving IC. ing. The photodiodes 8 are arranged at a predetermined pitch so as to output four phases whose phases are shifted from each other by 90 ° with respect to the scale 1, and this also serves as an index scale.

The wiring 6 is also formed of a laminated film of a TiSi2 film and an Au film in this embodiment, as in the previous embodiment. As a manufacturing process, first, after forming the photodiode 8 on the glass substrate 4, the wiring 6 may be formed in the same process as in the previous embodiment. Specifically, in the case of this embodiment, the wiring 6 is a lead wiring 6 from each photodiode 8.
a, and a wiring 6b for connecting a plurality of these lead wirings 6a, each having a multilayer wiring structure. In this case, it is preferable to use an SOG film as the interlayer insulating film. The wiring 6 is also covered with the SOG film 7 in this embodiment, as shown in FIG. In this embodiment, the SOG film 7 is applied so as to cover the array of the photodiodes 8.

FIG. 5 shows a schematic configuration of an embodiment in which the present invention is applied to a capacitance type encoder. The scale 100 is formed by arranging transfer electrodes 102 on an insulating substrate 101 such as glass. The transmission / reception integrated device 110 which is disposed so as to be relatively movable with a predetermined gap with respect to the scale 100 is provided on an insulating substrate 120 such as glass.
A transmission electrode 111 and reception electrodes 112 and 113 that are capacitively coupled to the transfer electrode 102 on the scale 100 side are formed, and are connected to the transmission electrode 111 and connected to the transmission IC 114 and the reception electrodes 112 and 113 for transmitting a transmission signal thereto. The receiving IC 115 is mounted. In such a capacitance type encoder, the transmission electrode 111 and the reception electrodes 112, 11 of the transmission / reception integrated device 110 are similar to the previous embodiment.
3 Further, a TiSi2 film and an Au
A stacked structure of films is used. In this embodiment, the transmission electrode 111 and the は reception electrodes 112 and 113 are also shown in FIG.
As shown in (b), it is covered with the SOG film. As a result, a high-performance capacitive encoder can be obtained.

The present invention is not limited to the above embodiment. For example, in the embodiments, the transmission type optical encoder has been described as an example, but the present invention can be similarly applied to a reflection type optical encoder. The present invention is also effective when an index grating is provided separately from the light receiving IC chip.
It can be formed by a laminated film of two films and an Au film. Further, the integrated device structure of the present invention is not limited to an optical encoder and a capacitance encoder, and can be applied to various other length measuring devices and the like. The present invention is also effective when a ceramic substrate or a silicon substrate covered with an insulating film such as a silicon oxide film is used in addition to a glass substrate as the insulating substrate.

[0021]

As described above, in the integrated device according to the present invention, a low resistance wiring can be obtained by using a laminated film of a TiSi2 film and an Au film as a wiring material. In particular, by interposing the TiSi2 film under the Au film, the Au film can be formed with excellent adhesion to the insulating substrate, and a highly reliable wiring can be obtained. Further, when the integrated device according to the present invention is applied to an encoder or the like, it becomes possible to extract a small signal with a low-resistance signal wiring and to perform a signal processing with a high S / N, thereby obtaining a high-performance encoder. Can be

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an optical encoder according to an embodiment of the present invention.

FIGS. 2A and 2B are a plan view and a cross-sectional view illustrating a main structure of the embodiment. FIGS.

FIG. 3 is a diagram showing a wiring forming step of the embodiment.

FIG. 4 is a plan view and a sectional view showing a light receiving integrated device according to another embodiment of the present invention.

FIG. 5 is an exploded perspective view showing a capacitive encoder according to another embodiment of the present invention.

[Explanation of symbols]

1 scale, 2 light source, 3 light receiving integrated device, 4
... glass substrate, 5 ... light receiving IC chip, 6 ... wiring, 61 ...
TiSi2 film, 62 ... Au film, 7 ... SOG film.

Claims (5)

[Claims] An insulating substrate, wiring formed by patterning a laminated film of a titanium silicide film formed on the insulating substrate and a gold film formed thereon, and a wiring mounted on the insulating substrate. An integrated device comprising: a circuit element having a terminal connected to a wiring. 2. The integrated device according to claim 1, wherein said insulating substrate is a glass substrate. 3. A scale on which an optical grating is formed, a light source for irradiating light to the scale, and a light source irradiating the scale with the light source with a predetermined gap relative to the scale. An optical encoder comprising a light receiving integrated device that modulates and transmits transmitted light or reflected light, wherein the light receiving integrated device comprises: an insulating substrate; a titanium silicide film formed on the insulating substrate; An optical encoder, comprising: a wiring formed by patterning a laminated film of a gold film formed thereon; and a light receiving IC mounted on the insulating substrate and having a terminal connected to the wiring. 4. The optical encoder according to claim 3, wherein the light receiving IC is flip-chip mounted on the insulating substrate. 5. A scale in which electrodes are arranged at a predetermined pitch and a transmission / reception integrated device in which transmission / reception electrodes are formed so as to be relatively movable with respect to the scale and are capacitively coupled to electrodes of the scale. In the capacitive encoder, the transmitting / receiving integrated device may include an insulating substrate, and a transmitting / receiving electrode formed by patterning a laminated film of a titanium silicide film formed on the insulating substrate and a gold film formed thereon. A capacitive encoder comprising: