JPS61196281A - Substrate for display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial applications,] The present invention relates to a display device substrate.

[Background of the invention]

Various display devices such as liquid crystal, EL, EC, FDP, and fluorescent display tubes have all reached the stage of practical use, and it can be said that the current goal is high-density matrix type displays.

For display systems that have problems with matrix driving, an "active matrix" method that uses active addition elements in each display section is effective.

By using a thin film nonlinear resistance element in a display device, high-density, high-quality display is possible, and its superiority as an active element for display is disclosed in the previous application (Patent Application No. 167945-1983).
No.). Furthermore, although there is a photovoltaic element (solar cell) as an element with a similar structure, the required characteristics and structure of the element are different, so the processing technology of the element cannot be used as is. In addition, there is semiconductor technology as a fine patterning technology, but since it is for display devices, it has a unique element arrangement and the film quality and thickness are different, so it cannot be used as is. . Therefore, in the present invention, protrusions are formed around the element during the manufacturing process of the active substrate so that the mask and the substrate come into uniform contact when the masks are aligned, thereby preventing variations in the element due to mask warping or resist peeling ( There is a need for an active substrate that prevents pattern collapse (resist pattern collapse), has less device variation, and has a high yield.

[Prior art and problems]

Conventionally, microfabrication techniques for nonlinear resistance elements having a structure in which a semiconductor layer is sandwiched between upper and lower electrodes have rarely been used, and semiconductor processing techniques have generally been used. However, since the films used and processed for display devices are different,
Improvements are needed in many respects. When used in a display device, the area occupied by the element is smaller than that of the display electrode. In the case of a transmissive display device, this affects the aperture ratio, and the smaller the element area, the brighter the display. Therefore.

In order to make the element area as small as possible, the element area is small compared to the distance between the elements, and the parts that touch the mask are point contacts, and the mask is locally pushed.

The mask becomes partially distorted. Therefore, when an IC grade mask is used, variations occur in the area or shape of the element, resulting in an element with variations in characteristics. When element variations occur, display unevenness occurs and the display quality deteriorates. Therefore, there is a need for a method that allows the use of an IC-grade mask and can form uniform elements over the entire surface even if the proportion of the elements on the display substrate is small.

[Purpose of the invention]

An object of the present invention is to form protrusions on the active substrate during the manufacturing process of the thin film nonlinear resistance element in an active substrate having a thin film nonlinear resistance element for a display device, and to improve mask alignment during the manufacturing process of the nonlinear resistance element. In this case, the substrate and mask are in uniform contact, and the resist can be formed on the substrate in the same way as the pattern shape on the mask. By eliminating variations in the element shape within the substrate, a uniform and stable thin film nonlinear resistor can be created. An active substrate for a display device having an element is provided.

[Structure of the invention]

The present invention provides an active substrate for forming a thin film resistive element for a display device including a first electrode layer, a semiconductor layer, an interlayer insulating film, and a second electrode layer formed on the substrate. In order to eliminate the gap unevenness between the mask and the substrate, which is caused by the steps created by etching each of the above layers during the photolithography process for processing to the desired size, protrusions are formed around the thin film nonlinear resistance element, and the mask is The contact area between the mask and the substrate is increased to ensure uniform contact between the mask and the substrate. In the case of a display device, a substrate with good display quality is one in which the area supported by the display electrodes is small compared to the area occupied by the elements. In addition, since there is a large difference in thickness between the element and the display electrode, when using a contact type exposure device, the part that comes into contact with the mask is the element part, and the contact pressure against the mask varies depending on the location, so the mask may This results in distortion, resulting in a pattern shape that differs from the intended element shape.

Therefore, during the element manufacturing process, protrusions with the same or similar height as the element part are formed around the element, which has a severe pattern accuracy, affects display quality, and is thick. Form the element into the desired element shape so that it has the same height as the part.

The protrusions have the same structure as the element ζ, and can be formed by performing the same process when patterning the element. Thereby, the manufacturing process is not increased by the formation of the protrusions. Also, as mentioned above, the protrusion needs to be close to the element to some extent, and the location where the protrusion is formed is determined by the warpage of the mask.
It is within 200 μm from the element and is formed around the element.

In addition, especially when the second electrode cut is as thin as 5ooA to 1 μm and the electrode width is as thin as 20 μm or less, the second electrode
When the electrode crosses, the unevenness of the protrusion causes wire breakage or an increase in wiring resistance, so it is formed in a portion other than the second electrode. Furthermore, if the protrusions are peeled off from the substrate during the process of forming the protrusions, or if the constituent film is peeled off due to over-etching during etching, the contact pressure at the peeled part changes, causing variations in the element shape, or The peeled off material transfers to other parts and adheres to the substrate, causing defects in the device and degrading the display quality. Therefore, considering the height of the element and considering the etching accuracy, the protrusions should be 1 μm x 1
μm or more is better. Also, it may be other than square, as long as the length of the lowest side is 1 μm or more. Further, by using amorphous silicon as the semiconductor layer, in which Pi and N type impurities can be controlled by impurity ions, a nonlinear resistance element having good characteristics can be formed at low temperature.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an example of a substrate for a display device using the present invention. FIG. 1 (Al is a plan view of a pixel portion of a display device substrate (active substrate).

Each pixel used an element in which diodes were arranged in a ring shape with upper and lower wiring. FIG. 1(B) is a cross-sectional view along a-b, (q is a cross-sectional view along c-d, and (5
shows an equivalent circuit diagram of the pixel section. In Figure 1, 1
is a glass substrate, Corning 7059 glass, NA
40 glass or Pyrex glass, and 2 is a transparent electrode made of ITO or 5n02. 6 uses amorphous silicon as the semiconductor layer, and 4 uses S as the interlayer insulating film.
iO□, Si, N4. PSG, spin-on glass or
An organic film (such as PIQ) is used, 5 is a wiring electrode, and At
, Cr, Nt, Mo or ITO. 6 and 7
This is the protrusion of the present invention, and the structure is as follows: from the lower layer, the protrusion 6 is made of a transparent electrode, a semiconductor layer, and an insulating film between the eyebrows, and the protrusion 7 is made of a transparent electrode and a semiconductor layer.

Further, in the equivalent circuit shown in FIG. 1 p), 8 is a wiring electrode, 9 is a display electrode, 10 and 10' are diodes, and 10 and 10' are connected in opposite directions. Second
The figure is a sectional view showing an IJ process of an interlayer insulating film with large irregularities formed on an active substrate. Board 1
1 and mask 16 are pressed together and light is irradiated to bake the photosensitive resist onto the insulating film. Figure 2 (
A) is the case when a conventional board is used, and Fig. 2 (B)
shows the case where a substrate having protrusions of the present invention is used. The difference between Figure 2 (5) and Figure 2 (B) is as shown in the figure.
The problem lies in whether the mask 16, 16' is bent on the semiconductor layer 16 and the desired pattern can be formed with few errors.

In Fig. 2 (-), the mask 16 is bent on the semiconductor layer, whereas in Fig. 2 (B), the mask 16' and the protrusions 17 around the element' come into contact to reduce the bending. Figure 2 shows the state in which the pattern is uniform.

In FIG. 2, 11 is a glass substrate, 12 is ITo, 1
Amorphous silicon for 3, 5IO2 for 14, 0 for 15
An example is shown using FPR resist, quartz mask at 16 and 16', and ITO, amorphous silicon, and Sin at 17 from the bottom layer.

〔Effect of the invention〕

As is clear from the above explanation, by using the present invention, even if the distance between each element is large and the substrate configuration has large unevenness, the patterning accuracy (mask alignment accuracy) of each component can be improved. It is believed that this technology will improve the performance (including), enable the formation of fine pattern elements, enable the formation of active substrates for high-density displays, and contribute to the development of display devices using active elements.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, and FIG. 1 (5) is a plan view of the pixel portion of the active substrate.
1 (q is a sectional view of c - d). FIG. e) IJ process is shown in FIG. 2 (N is a conventional technique, and FIG. 2 (B) is a sectional view showing the present invention. 1.11...Substrate, 2.12... ...Transparent electrode, 3.16...Semiconductor layer, 4.14...Interlayer insulating film, 6.7.17...Protrusion, 16.16'. ·····mask.

Claims (4)

[Claims] (1) In an active substrate having a thin film nonlinear resistance element for a display device consisting of a first electrode layer formed on the substrate, a semiconductor layer, an interlayer insulating film, and a second electrode layer, a nonlinear resistance element is formed on the active substrate. 1. A display device substrate comprising a protrusion having a height at least half that of a resistive element. (2) The display device substrate according to claim 1, wherein the protrusion is made of a film having the same structure as the nonlinear resistance element. (3) The substrate for a display device according to claim 1, wherein the size of the protrusion is 1 μm×1 μm or more. (4) The display device substrate according to claim 1, wherein the protrusion is located within 200 μm from the active element.