JPH11149094A - Active matrix substrate manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active matrix substrate manufacturing method in which an active element is formed by using a polycrystalline Si thin film melt-crystallized with a linear laser beam, the unevenness occurring in an optical window at the time of laser beam irradiation. Variations in the characteristics of the active elements caused by excessive contamination are suppressed, and the display quality is maintained high. SOLUTION: A dummy Si thin film 21 is provided in a portion 20 not used for display on a substrate (not used for a screen and a drive circuit),
The amount (area) of the dummy Si thin film 21 is adjusted so that the optical window becomes substantially uniformly stained when a linear laser beam is irradiated.

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 an active matrix substrate for manufacturing an active element using a polycrystalline Si thin film melt-crystallized with a linear laser beam, and more particularly to a method for manufacturing a peripheral driving circuit and a polycrystalline silicon for a screen portion. The present invention relates to a method for manufacturing an active matrix substrate for a liquid crystal display device using a Si thin film transistor.

[0002]

2. Description of the Related Art FIG. 3 is a schematic view of a conventional arrangement of an active matrix substrate used for a liquid crystal display device using a peripheral drive circuit and a polycrystalline Si thin film transistor for a screen portion, in which Si for a transistor is formed in an island shape. Is shown. Usually, a plurality of active matrix substrates are often formed on one substrate, and here, nine active matrix substrates 2 for liquid crystal display devices are arranged on the substrate 1. One active matrix substrate has a screen section 3 and peripheral drive circuit sections 4a and 4b, and an Si thin film 5 necessary for a thin film transistor is formed in an island shape in each section.

In a conventional method of manufacturing an active matrix substrate using a polycrystalline Si thin film melt-crystallized with a linear laser beam as an active element, an Si thin film separated into islands is arranged as shown in FIG. The substrate 1 is irradiated with a linear laser beam 8 from a laser beam light source 6 through an optical window 7 as shown in FIG. This linear laser beam 8 has a linear irradiation energy distribution on the surface of the substrate 1 and is substantially uniform in the major axis direction. Further, the beam irradiation position is sequentially shifted in a direction having an angle with the major axis direction of the laser beam 8 (in this case, the laser is fixed, and the stage 9 on which the substrate 1 is placed at an angle of 90 degrees with the major axis of the laser is slightly moved. Are shifted in the direction of the arrow.
Conversely, the substrate may be fixed and the laser beam side may be moved.) The Si thin film 5 separated into islands on the substrate 1 is melt-crystallized and changed into a polycrystalline Si thin film 10.

Thereafter, an active matrix substrate is manufactured by using an active element (for example, a thin film transistor) formed from the polycrystalline Si thin film 10. At this time, the irradiation atmosphere may be made uniform by placing the substrate 1 in the chamber 11.
Items related to the above configuration (LC using laser crystallized Si
D) is introduced, for example, on pages 190 to 193 in the magazine Flat Panel Display 1994 (published by Nikkei BP: 1993).

[0005]

When an active matrix substrate using an active element made of polycrystalline Si is applied to a display device, a screen portion is naturally formed with a peripheral drive circuit in order to ensure display uniformity. It is required that the characteristics of the elements to be manufactured have small variations. This is particularly important when performing a display requiring high accuracy, such as a moving image display or a computer monitor display.

However, in the conventional method of manufacturing an active matrix substrate using a polycrystalline Si thin film melt-crystallized with a linear laser beam as an active element (particularly a thin film transistor) shown in FIGS. As the process is performed, the optical window 8 becomes contaminated with the scattered substance 12 at the time of irradiation from the substrate 1 side. This is an island Si
It is considered that contaminants remaining on the edge or Si itself is partially scattered. The degree of the contamination strongly depends on the distribution of the island-shaped Si thin film, and the more the Si is irradiated on the densely arranged portion, the more the Si is deposited. For example, FIG.
The portion a is the most soiled, and then the portions b and c are soiled in this order. Therefore, when the optical window 8 is not contaminated, the melt crystallization is performed uniformly, and the active element is obtained with uniform characteristics. Changes depending on the location due to the contamination of the window, and as a result, uniform characteristics of the active element cannot be obtained.

That is, the average energy loss can be improved by increasing the energy from the light source, but there is a problem that uniform characteristics cannot be obtained. Of the optical window 8,
In particular, the portion corresponding to the peripheral drive circuit section 4a is most soiled.
If the energy is increased to secure the driving capability of the peripheral drive circuit section 4a, the energy is excessively added to the screen portion 3 and the signal holding performance of the elements in the screen portion is likely to deteriorate.

An object of the present invention is to provide a method of manufacturing an active matrix substrate which can suppress the variation in the characteristics of the active element due to the dirt on the optical window and can perform the production while maintaining a high display quality. I do.

[0009]

In order to achieve the above object, a first means of the present invention is to dispose a dummy Si thin film on a substrate side so that an optical window is contaminated as uniformly as possible. The second means of the present invention irradiates the optical window with a laser beam by shifting the positions of the plurality of substrates for each substrate. That is, the most dirty portion of the optical window is sequentially shifted.

Thus, since the optical window is substantially uniformly stained, it is possible to suppress variations in the characteristics of the active element due to the stain on the optical window.

[0011]

Therefore, according to the first aspect of the present invention, a substrate having an Si thin film separated in an island shape is irradiated with a linear laser beam through an optical window; By shifting the beam irradiation position in a direction having an angle with the major axis direction, the Si thin films separated into islands on the substrate are sequentially melt-crystallized to obtain polycrystalline Si.
In a method of manufacturing an active matrix substrate using an active element formed from the polycrystalline Si thin film as a thin film,
A dummy island-shaped Si thin film is disposed on a portion of the substrate not used for display so that the optical window is substantially uniformly contaminated.

[0012] The invention described in claim 2 of the present invention provides:
A substrate having an Si thin film separated into islands is irradiated with a linear laser beam through an optical window, and a beam irradiation position is shifted in a direction having an angle with a major axis direction of the laser beam, thereby forming a substrate on the substrate. In the method of manufacturing an active matrix substrate using an active element formed from the polycrystalline Si thin film by sequentially melting and crystallizing the Si thin film separated into islands to form a polycrystalline Si thin film, the optical window is substantially uniformly contaminated. As described above, a laser beam is applied to a plurality of substrates while the positional relationship between the optical window and the substrates is shifted for each substrate.

In any of the first and second aspects of the present invention, since the optical window is more uniformly contaminated than in the prior art, it has the effect of reducing the variation in the characteristics of the active elements in the active matrix substrate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (Embodiment 1) FIG. 1 shows a method of manufacturing an active matrix substrate according to Embodiment 1 of the present invention, wherein 1 is a substrate, and a plurality of active matrix substrates 2 are arranged. Reference numeral 3 denotes a screen portion, 4a and 4b denote peripheral drive circuit portions, and 5 denotes an Si thin film separated in an island shape. Reference numeral 20 denotes a portion not used for display on the substrate (not used for a screen and a drive circuit), and reference numeral 21 denotes a dummy Si thin film.

The dummy Si thin film 21 has a thickness of 1000 °
Is obtained by annealing amorphous Si by plasma CVD at 400 ° C. and patterning the dehydrogenated thin film by a photoetching process, and is formed simultaneously with the Si thin film 5 for the thin film transistor. The same linear laser beam as in Fig. 4
(XeCl excimer laser 300 Hz oscillation 200 W linearly beam-formed), the optical window 7
Amount (area) of dummy Si thin film 21 so that
Has been adjusted. At this time, laser irradiation is performed in a vacuum using the chamber 11. By this laser irradiation, Si
Is melt-crystallized into a polycrystalline Si thin film.

Thereafter, processes such as gate insulating film and gate electrode, ion implantation and annealing, interlayer insulation and electrode formation, and passivation are performed to form a polycrystalline Si thin film transistor, and an active matrix substrate for liquid crystal display is formed. .

When manufacturing according to the first embodiment,
The optical window 7 is substantially uniformly contaminated, and variations in element performance can be suppressed only by adjusting the energy of the light source with respect to the overall contamination of the optical window. In this method, production can be continued with less maintenance of the optical window.

(Embodiment 2) FIG. 2 shows a method of manufacturing an active matrix substrate according to Embodiment 2 of the present invention. The substrate 1 is irradiated with the linear laser beam 8. At this time, the position of each substrate is shifted in the major axis direction of the laser beam 8 by d for the processing of a plurality of substrates, and is moved in the direction of the arrow 30. . The value of d is adjusted so that the optical window 7 is substantially uniformly stained.

More specifically, laser irradiation is performed in a positional relationship at five locations, shifted by about the width of the peripheral drive circuit 4a (vertical direction in the drawing). That is, the portion that irradiates the peripheral drive circuit 4a where the optical window is most stained is dispersed in the optical window 7 at five locations. At this time, laser irradiation is performed in a vacuum using a chamber. The laser irradiation melts and crystallizes Si to change into a polycrystalline Si thin film.

Thereafter, processes such as gate insulating film and gate electrode, ion implantation and annealing, interlayer insulation and electrode formation, and passivation are performed to form a polycrystalline Si thin film transistor, and an active matrix substrate for liquid crystal display is formed. .

In the case of the manufacturing method according to the second embodiment, the frequency of maintenance of the optical window can be reduced, and the energy of the light source for the overall contamination of the optical window 7 can be adjusted.
Production can be continued for a long time in a state where variation in element performance is suppressed.

[0022]

As described above, according to the present invention,
Variations in element performance due to non-uniformity of dirt on the optical window are suppressed, and only by adjusting the energy of the light source for overall dirt on the optical window, the frequency of maintenance of the optical window is reduced and uniform characteristics are obtained. Active matrix substrates can be produced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for manufacturing an active matrix substrate according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method for manufacturing an active matrix substrate according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a layout of a conventional active matrix substrate.

FIG. 4 is a view showing an irradiation method of a linear laser beam.

[Description of Signs] 1 Substrate 2 Active matrix substrate for liquid crystal display device (for one liquid crystal display device) 3 Screen portion 4a, 4b Peripheral drive circuit portion 5 Si thin film separated into islands 6 Laser beam light source 7 Optical window 8 Laser beam 9 Stage 10 Polycrystalline Si thin film 11 Chamber 12 Scattered substance from substrate side 20 Unused part for display 21 Dummy Si thin film 30 Moving direction of substrate

Claims (3)

[Claims] A substrate having an Si thin film separated into islands is irradiated with a linear laser beam through an optical window,
And, by shifting the beam irradiation position in a direction having an angle with the major axis direction of the laser beam, the Si thin films separated into islands on the substrate are sequentially melt-crystallized to obtain polycrystalline S
In a method of manufacturing an active matrix substrate using an active element formed from the polycrystalline Si thin film as an i-thin film, a dummy portion is provided on a portion of the substrate not used for display so that the optical window is substantially uniformly contaminated. A method for manufacturing an active matrix substrate, comprising arranging island-shaped Si thin films. 2. A substrate having an Si thin film separated into islands is irradiated with a linear laser beam through an optical window.
And, by shifting the beam irradiation position in a direction having an angle with the major axis direction of the laser beam, the Si thin films separated into islands on the substrate are sequentially melt-crystallized to obtain polycrystalline S
In a method of manufacturing an active matrix substrate using an active element formed from the polycrystalline Si thin film as an i-thin film, the optical window and the substrate are disposed on a plurality of substrates so that the optical window is substantially uniformly contaminated. A method for manufacturing an active matrix substrate, comprising irradiating a laser beam with a positional relationship shifted for each substrate. 3. The method for manufacturing an active matrix substrate according to claim 1, wherein the laser beam is a pulse laser using an excimer laser.