JPH03157624A - Production of thin-film transistor - Google Patents

Abstract

PURPOSE:To simplify the process for production by forming the resist of the reversal patterns of the opaque electrodes of gates-sources and drains by back exposing of a light shielding film and using this resist as a photomask or making self-matching formation by a lift-off method. CONSTITUTION:A gate electrode material consisting of Cr or Au is formed by sputtering on a transparent insulating substrate 1 and the gate electrodes 2 are formed by a photolithography method. A gate insulating film 3 consisting of Si oxide and a semiconductor film 4 consisting of amorphous Si are then formed by a P-CVD method and are patterned by the photolithography method. A transparent conductive film consisting of ITO is then formed by a sputtering method to form display electrodes 5. An Al film is then formed and after the source electrodes and drain electrodes 6 are formed, an insulating film 7 consisting of Si oxide is formed by P-CVD. the semiconductor film 4 is completely covered by the aggregated segments formed continuously with the gate electrodes 2, the source electrode and drain electrodes 6. A negative resist is then applied over the entire surface of the insulating film 7 and is subjected to the back exposing, by which the light shielding film 10 is formed on the aggregated blocks via the resist patterns 9 reversed from the aggregated blocks of the electrodes 2, 6, etc. The TFTs are thus formed.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to thin film transistors (hereinafter referred to as TPT),
In particular, the present invention relates to a method of manufacturing TPT suitable for transistor arrays for active matrix liquid crystal display devices.

(b) Conventional technology In recent years, advances in amorphous semiconductor film formation technology have made it possible to form large quantities of TPTs with uniform switching characteristics on the same substrate. type liquid crystal display devices are being put into practical use.

FIG. 4 shows a sectional view of a TFT portion of a conventional TFT array for a liquid crystal display device. The TPT shown in the figure has a gate electrode 2, a gate insulating film 3, an amorphous semiconductor 111!4, a display electrode 5, a source electrode and a drain electrode 6, an insulating film 7, and a light shielding film 7 on a transparent insulating substrate 1 such as glass. The film 8 is sequentially laminated. The light shielding film 8 shown in the figure is formed in a size that can cover the amorphous semiconductor 81!4 in order to prevent the TPT from malfunctioning due to the amorphous semiconductor film 4 receiving light (specially To manufacture the TPT shown in the figure, first, a gate electrode material is formed on an insulating substrate such as glass by a sputtering method, a vapor deposition method, etc., and a gate electrode 2 is formed by a photolithography method or the like. Next, on top of that, a gate isolation It film 3 and an amorphous semiconductor film 4 are formed.
are sequentially formed into films by a P-CVD method or the like, and then patterned by a 7-otrin graph method or the like. After that, a display electrode 5 is formed using a transparent conductive film, a source electrode and a drain electrode 6 are formed using a metal such as AI, and an insulating film 7 that becomes a protective film for TPT is formed on the entire surface of the substrate on which these electrodes are formed. Form a film. Finally, a light shielding film 8 is formed on the amorphous semiconductor film 4 using an opaque, ie non-optical, metal film or the like.

(c) It has been pointed out that the conventional TPT manufacturing method, as described in Section 1, which the invention aims to solve, has the problem of high costs due to the complicated manufacturing process, which leads to a reduction in the number of masks used and There is a demand for process simplification.

In view of these problems, it is an object of the present invention to provide a manufacturing method that particularly simplifies the manufacturing process of a light-shielding film and can obtain a high-performance TPT.

(d) Means for Solving the Problems The TPT manufacturing method of the present invention involves forming a resist with an inverted pattern of the opaque FIII electrodes of the gate, source, and drain using a light-shielding film as a backside exposure, and using the resist as a mask. By using the lift-off method described above, each opaque electrode of the gate, source, and drain is formed in a self-aligned manner with respect to the assembled TPT section.

(E) Function According to the present invention, the number of masks for patterning can be reduced by using the self-alignment method, and furthermore, the etching and notching steps can be omitted by applying the lift-off method, resulting in a simple process. It becomes possible to create a high-performance TPT using this method, and it is possible to reduce manufacturing costs.

(F) Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a sectional view of the TPT, and FIG. 2 shows a plan view. Moreover, FIGS. 3(a) to 3(d) show cross-sectional views in the order of steps.

First, a gate electrode material made of chromium or gold is formed on a transparent insulating substrate 1 made of glass or the like by a sputtering method, a vapor deposition method, etc., and a regate electrode 2 is formed by an otolithography method or the like. A gate insulating film 3 made of silicon oxide or silicon nitride and a semiconductor film 4 made of amorphous silicon are sequentially formed thereon by a P-CVD method or the like, and then patterned by a photolithography method or the like.
Figure 3(b)]. By patterning at this time, the semiconductor film 4 is placed on the gate electrode 2.

Next, a transparent conductive film made of ITO material is applied by sputtering or the like, and display electrodes 5 are formed by 7-otolithography or the like. Thereafter, a film of metal such as AI is applied by sputtering, vapor deposition, etc., a source electrode and a drain electrode 6 are formed by 7 otolithography, etc., and then an insulator made of dinocone oxide or silicon nitride, etc. is formed by P-CVD, etc. A film 7 is formed [FIG. 3(C)]. At this time, the source electrode and drain electrode 6 are provided on the semiconductor 1114 to be separated from each other, and are in a positional relationship that partially overlaps with the gate electrode 2, so that the gate electrode 2,
The semiconductor film 4 is completely covered by the continuous collection section of the source electrode and the drain electrode 6.

Next, a negative resist is applied to the entire surface of the insulating film 7,
By back exposure, a resist pattern 9 is obtained in which the collective sections of the opaque gate electrode 2, source electrode, and drain electrode 6 are reversed. [Figure 3(d)]. Note that the dimensions of the resist pattern 9 at this time can be controlled by the exposure amount.

Thereafter, a non-transparent metal film such as chromium is formed on the resist pattern 9 formed as shown in FIG. 3(d) and the insulating film 7 exposed from the resist pattern 9.
By forming the light-shielding film 10 in a self-aligned manner with respect to the collective section of the opaque gate electrode 2, source electrode, and drain electrode 6 by using as a mask or using the 7-off method,
A TPT equipped with a light shielding film 10 as shown in FIG. 1 can be manufactured. Note that this light-shielding film 10 covers the hatched electrode collection section as shown in the plan view of FIG. 2, so it can be placed not only at the TPT position but also at the grid-like pixel gap positions like a black matrix mask. will be done.

(G) Effects of the Invention According to the TPT manufacturing method of the present invention, the light-shielding film covering the semiconductor film forms a resist with an inverted pattern of the opaque electrodes of the gate, source, and drain by back exposure, and the resist is masked. The lift-off method described above enables formation in a self-aligned manner, thereby simplifying the manufacturing process and reducing manufacturing costs. Moreover, since this light-shielding film can reliably shield the semiconductor film from light, it is possible to obtain a highly reliable TPT that is especially suitable for TPT arrays for liquid crystal display devices that are used under light irradiation, such as LCD TV panels that use backlights. can.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of TPT obtained by the manufacturing method of the present invention, FIG. 2 is a plan view of a TPT array obtained by the manufacturing method of the present invention, and FIGS. 3(a) to 3(d) are TPTs showing the method of the present invention. FIG. 4 is a cross-sectional view of a conventional TPT.

Claims (1)

[Claims] (1) In a thin film transistor in which an opaque gate electrode, a semiconductor film, an opaque source, a drain electrode film, and a light-shielding film are laminated on a transparent insulating substrate, the light-shielding film is exposed to the back side to form the gate, source, and drain. A method for manufacturing a thin film transistor, characterized in that a resist having an inverted pattern of each opaque electrode is formed, and by a lift-off method using the resist as a mask, the opaque electrodes are formed in a self-aligned manner with respect to each opaque electrode of the gate, source, and drain. .