JPH10186399A - Liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of dielectric breakdown by the static electricity of interlayer insulating film by deviating the edges of active or wiring films superposed from each other across the interlayer insulating film when viewed from above. SOLUTION: The edges e1 to e3 of a polysilicon film 6 of a first layer, a polysilicon film 8 of a second layer and the aluminum wiring film 11 exist at the points deviating from each other when viewed from above. The deviation direction of the edges e1, e2 and the deviation direction of the edges e2 and e3 are reversed. Namely, the edge 2e of the polysilicon film 8 of the second layer on the polysilicon film 6 of the first layer exists on the inner side with respect to the edge e1 of this film and deviates in the direction where the edge e1 of the polysilicon film 6 of the lower side is visible from above. The edge e3 of the wiring film 10 consisting of aluminum on the polysilicon film 8 of the second layer exists on the outer side with respect to the edge e2 of this film and the edge e3 of the wiring film 10 on the upper side deviates in the direction where this edge protrudes from the wiring film 8 on the lower side when viewed from below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal device, and more particularly to a liquid crystal device having a multilayer wiring formed on a glass substrate.

[0002]

2. Description of the Related Art A liquid crystal device comprises a plurality of gate lines and a plurality of signal lines arranged orthogonally, and a switching transistor and an auxiliary capacitance element formed of a thin film transistor corresponding to each intersection, and a pixel. FIG. 3 is a plan view showing a switching transistor, an auxiliary capacitor, and other wiring films of such a liquid crystal device.
This is for pixels. Such pixels are arranged vertically and horizontally. Reference numeral 1 denotes a semiconductor thin film made of a first polysilicon film, which forms an active film of a switching transistor and a lower electrode of an auxiliary capacitance element. 2g is a second-layer polysilicon film forming a gate electrode and a wiring, 2c is a second-layer polysilicon film forming an upper electrode of the auxiliary capacitance element, and 3 is a contact hole between the switching transistor and the aluminum wiring film 4. is there.

[0003] Such a liquid crystal device is used in a limited area.
That is, it is necessary to form a switching transistor and an auxiliary capacitance element in one pixel region, and the auxiliary capacitance element almost completely connects the upper electrode 2c and the semiconductor thin film 1 in order to increase the capacitance value per unit area as much as possible. The active or wiring layers forming the multi-layer wiring film are overlapped (however, in FIG. 3, they are not shown if they are overlapped, but they are shifted because they are not understood, but the edges are actually overlapped). Were overlapped as shown in FIG.

In FIG. 4, 5 is a glass substrate and 6 is a first substrate.
7th layer polysilicon film (eg, 0.05 μm thickness)
Is an insulating film made of a thermal oxide film (SiO2) or a nitride film (SiN), 8 is a wiring film made of a second polysilicon film, 9 is an interlayer insulating film made of SiO2 or SiN, and 10 is a wiring made of aluminum. The film 11 is a passivation film. In this example, the edges of the first-layer polysilicon film 6, the second-layer polysilicon film 8, and the aluminum wiring film 11 are substantially overlapped when viewed from above.

[0005]

The liquid crystal device is based on a glass substrate 1 having an insulating property.
Since an active or wiring film is formed on the multilayer wiring with an insulating film interposed therebetween, it is easier to be charged in the process of laminating each layer, and therefore, the active film and the wiring film which overlap with each other via the interlayer insulating film are formed. If the edges between the wiring films or between the wiring films are close to each other, the electric field is likely to be concentrated on the edges, so that the electrostatic breakdown often occurs between the edges.

This is because the formation and patterning of the wiring film and the insulating layer are performed by plasma CVD, plasma etching, or the like, impurities are implanted by ion implantation, and the base glass substrate 1 is formed. Because of the insulating property, the electric charge charged on the substrate 1
This is because there is no possibility of escaping, and charges of several thousand volts easily accumulate on the upper and lower surfaces of the interlayer insulating film between the upper and lower wiring films. Therefore, when the edges between the wiring films are close to each other, electric field concentration is easily generated at the edges, and dielectric breakdown due to static electricity is easily induced.

[0007] When such an insulation breakdown occurs, a short-circuit failure or insulation failure naturally occurs, so that the failure rate increases.

The present invention has been made to solve such a problem. In a liquid crystal device having a multilayer wiring formed on a glass substrate, an edge between active or wiring films overlapping with an interlayer insulating film interposed therebetween. An object of the present invention is to make it difficult to cause dielectric breakdown due to static electricity of an interlayer insulating film, which occurs between them.

[0009]

According to a first aspect of the present invention, there is provided a liquid crystal device.
The edge of the nth (positive integer) active or wiring film and the (n + 1) th active or wiring film overlapping therewith via an interlayer insulating film are shifted from the top.

Therefore, according to the liquid crystal device of the first aspect, the edges of the active or wiring films overlapping with the interlayer insulating film interposed therebetween are shifted from the top, so that the distance between the edges becomes longer and longer. Can reduce the occurrence of dielectric breakdown due to static electricity in the interlayer insulating film, which is induced by the electric field concentration on the edge.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIGS. 1 and 2 are sectional views showing different embodiments of the liquid crystal device of the present invention. In the drawing, reference numeral 5 denotes a glass substrate, and 6 denotes a first-layer polysilicon film (having a thickness of, for example, 0.1 mm).
05 μm), 7 is an insulating film made of a thermal oxide film (SiO 2) or a nitride film (SiN), 8 is a wiring film made of a second polysilicon film, 9 is an interlayer insulating film made of SiO 2 or SiN, 10 is Wiring film made of aluminum,
Reference numeral 11 denotes a passivation film.

In this liquid crystal device, both the one shown in FIG. 1 and the one shown in FIG. 2 have the first polysilicon film 6, the second polysilicon film 8, and the edge of the aluminum wiring film 11. e1, e2, and e3 are located at positions shifted from the top. Then, the deviation amount, that is, e1 and e2
And the deviation amounts d1.2 and d2.3 viewed from above are 0.5 μm.
As described above, it is necessary to set a value larger than the film thickness of the interlayer insulating films 7 and 9. Otherwise, the current technology and the wiring rule do not sufficiently provide the effect of preventing dielectric breakdown due to static electricity, and the steps at the edges e1, e2, and e3 forming portions may become steep. Specifically, the effect of preventing dielectric breakdown can be obtained by setting the deviation amount to at least 0.5 μm, and the sharpness at the edge portion can be reduced by making the thickness larger than the thickness of the interlayer insulating film. it can.

The direction of the shift between the edges e1 and e2 and the direction of the shift between the edges e2 and e3 are reversed. That is, taking the liquid crystal device of FIG. 1 as an example, the edge e2 of the second-layer polysilicon film 8 above the edge e1 of the first-layer polysilicon film 6 is located inside, The edge e1 of the lower polysilicon film 6 is shifted in a direction in which it can be seen from above. The edge e3 of the wiring film 10 made of aluminum is located outside the edge e2 of the second-layer polysilicon film 8, and the lower wiring film 8 and the upper wiring The edge e3 of the film 10 is shifted in such a direction as to protrude.

In the case of the liquid crystal device shown in FIG. 2, the edge e2 of the second-layer polysilicon film 8 above the edge e1 of the first-layer polysilicon film 6 is located outside, and Is shifted in a direction in which the edge e2 of the upper polysilicon film 8 can be seen when viewed from above. Then, the second-layer polysilicon film 8 is formed.
The edge e3 of the wiring film 10 made of aluminum on the edge e2 is located inside, and the edge e3 of the upper wiring film 10 protrudes from the lower wiring film 8 when viewed from above. It is shifted. Also in this case, edges e2 and e
3 is reversed.

In this way, if the direction of the shift between the edges e1 and e2 and the direction of the shift between the edges e2 and e3 are reversed, the edge due to static electricity can be transferred to the edge due to static electricity without unnecessarily increasing the area occupied by the auxiliary capacitance element and the like. Of the interlayer insulating film, which is caused by the electric field concentration, can be made less likely to occur.

[0017]

According to the liquid crystal device of the present invention, since the edges of the active or wiring films overlapping with the interlayer insulating film interposed therebetween are shifted from the top, the distance between the edges becomes longer, and the edges are longer. It is possible to suppress the occurrence of dielectric breakdown due to static electricity of the interlayer insulating film, which is induced by the electric field concentration on the interlayer insulating film.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a liquid crystal device of the present invention.

FIG. 2 is a cross-sectional view illustrating another embodiment of the liquid crystal device of the present invention.

FIG. 3 is a plan view of the liquid crystal device.

FIG. 4 is a sectional view showing a conventional example of a liquid crystal device.

[Explanation of symbols]

5 ... glass substrate, 6 ... active film, 7 ... interlayer insulating film, 8 ... wiring film, 9 ... interlayer insulating film, 10 ...
-Wiring film, e1, e2, e3 ... edge.

Claims (3)

[Claims] In a liquid crystal device having a multilayer wiring formed on a glass substrate, an nth (positive integer) active or wiring film and an (n + 1) th active or wiring film overlapping therewith via an interlayer insulating film are provided. Liquid crystal device characterized in that the edges are shifted when viewed from above 2. The shift direction of the edge between the nth active or wiring film and the (n + 1) th active or wiring film overlapping the nth active or wiring film, and the (n + 1) th active or wiring film and the (n + 2) th active or wiring film. 2. The liquid crystal device according to claim 1, wherein the directions of shifting the edges are opposite to each other. 3. The amount of edge shift between the n-th active or wiring film and the (n + 1) -th active or wiring film overlapping therewith via the interlayer insulating film depends on the thickness of the interlayer insulating layer insulating the two layers. 3. The liquid crystal device according to claim 1, wherein the thickness of the liquid crystal device is larger than 0.5 μm.