Method of manufacturing MIM elements in liquid crystal displays

A method of forming a MIM element for use in liquid crystal displays. The MIM element is formed on a substrate using photolithography with a self-alignment method where one of the metal electrodes forming the MIM element acts as a radiation mask to radiation use in forming the element.

BACKGROUND OF THE INVENTION 
The present invention is directed to a method of manufacturing a liquid 
crystal display having a large capacity in which thin film non-linear 
elements are provided in a substrate of a liquid crystal cell, and which 
can be driven with a high duty. 
A conventional method of manufacturing an electro-optic device 
incorporating metal-insulator-metal (hereinafter "MIM") elements is 
described in Japan Display '83, PP.404-407, 1983 by S. Morozumi, et al. 
FIG. 12 of the present application shows a section of one picture element 
in such a device. A first electrode 32 of the MIM element and an insulator 
33 are formed on a substrate 31 and then processed into a predetermined 
shape. Next, after forming a transparent picture element electrode 36 and 
processing it into a predetermined shape, an insulator 34 is formed on the 
side of the first electrode. Subsequently, a second electrode 35 of the 
MIM element is formed and processed such that it makes electrical contact 
with the transparent picture element electrode 36. 
According to the conventional manufacturing method, however, it was very 
difficult to achieve non-linear characteristics of the MIM element without 
degrading display quality of the electro-optic device. 
The present invention has been developed to overcome the foregoing 
disadvantage. The method of the present invention is intended to provide a 
large capacity liquid crystal display using non-linear elements which are 
formed by a self-alignment method using a negative type photo resist or by 
a combination of a self-alignment method using a positive type photo 
resist and a lift-off method to provide an element superior in non-linear 
characteristics. 
SUMMARY OF THE INVENTION 
Generally speaking, in accordance with the present invention, a method of 
manufacturing a liquid crystal display is provided. The display includes a 
row electrode formed on either one of two opposed substrates with a liquid 
crystal material therebetween, a column electrode formed on the other of 
the two substrates, and a MIM (Metal-Insulator-Metal) element coupled to 
each of the picture elements defined where the row and column electrodes 
overlap on at least one of the electrodes. The process of forming the MIM 
element is a photolithography process using a self-alignment method in 
which the substrate is exposed from behind with radiation with a first 
electrode of the MIM element as a radiation mask. 
The process of forming a second electrode of the MIM element may be of 
either a photolithography process using a self-alignment method in which a 
negative type photo resist is coated on the second electrode with the 
substrate being exposed from behind with the first electrode of the MIM 
element as a mask, or a lift-off method in which a positive type photo 
resist is coated on the insulator. 
The insulator may be formed on the first electorde in substantially the 
same pattern as the first electrode, or may be formed over substantially 
the entire surface of the substrate having the MIM elements formed 
thereon, except for the electrical connecting terminal portion of the 
substrate where coupled to an external control circuit of the liquid 
crystal display. 
A transparent electrode is formed on the second electrode to serve as a 
picture element electrode for displaying characters, figures and the like. 
As an alternative, the second electrode may itself be transparent to serve 
also as a picture element electrode directly. 
When forming the second electrode using a self-alignment method in 
accordance with the present invention, a process may be used where a photo 
mask is disposed on the rear surface of the substrate on which the MIM 
elements are to be formed, and exposure is then carried out from the rear 
of the substrate. 
The first electrode, insulator and the second electrode are preferably 
formed in a laminated configuration. To this end, the present invention 
provides either a method in which the first electrode is formed on the 
surface of the electrode substrate, and the insulator and the second 
electrode are formed thereon in this order in a laminated configuration, 
or a method in which the second electrode is formed on the surface of the 
electrode substrate, and the insulator and the first electrode are formed 
thereon in this order. In the former method, a self-alignment method is 
used with the first electrode as a reference when forming the second 
electrode, whereas in the latter method, a self-alignment is used with the 
second electrode as a reference when forming the first electrode. 
Accordingly, it is an object of the present invention to provide an 
improved method of manufacturing MIM elements. 
Another object of the present invention is to provide an improved method of 
manufacturing a liquid crystal display having MIM elements. 
A further object of the present invention is to provide an improved method 
of manufacturing MIM elements in a liquid crystal display having a large 
capacity which can be driven with a high duty. 
A still further object of the present invention is to provide a liquid 
crystal display having MIM elements manufactured in an improved process. 
Still other objects and advantages of the invention will in part be obvious 
and will in part be apparent from the specification. 
The invention accordingly comprises the several steps and the relation of 
one of more of such steps with respect to each of the others, and the 
article possessing the features, properties, and the relation of elements, 
which are exemplified in the following detailed disclosure, and the scope 
of the invention will be indicated in the claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A manufacturing method of an electro-optic device using nonlinear elements 
in accordance with the present invention will now be described with 
refgerence to FIGS. 1A.sub.1 through 1D.sub.2. FIGS. 1A.sub.1 through 
1A.sub.6 are views for explaining an outline of the manufacturing method 
in accordance with the present invention, and FIGS. 1B.sub.1 through 
1D.sub.2 are views for explaining the essential processes thereof. 
According to the manufacturing method of the present invention, a first 
electrode metal film 2 is formed on a glass substrate 1 (FIG. 1A.sub.1) 
and a given pattern is then defined with photo etching (FIG. 1A.sub.2). 
Next, an insulator 4 constituting a second layer is formed over the entire 
surface of metal film 2 except for a terminal portion thereof by any 
suitable method such as by mask sputtering, mask evaporation, or mask CVD 
(FIG. 1A.sub.3). Insulator 4 is formed of an insulating film 4a which has 
such a high density that is includes no pin holes and which has a uniform 
film thickness of about 100 .ANG.-1000 .ANG.. 
Subsequently, an ITO film 5 serving also as a picture element is formed 
over insulator 4 by magnetron sputtering (FIG. 1A.sub.4) and the desired 
pattern is obtained by photo-etching using a self-alignment method in 
which substrate 1 is exposured from behind by employing a negative type 
photo resist with the first electrode metal film 2 as a mask (FIG. 
1A.sub.5). Finally, a photolithography process is performed on substrate 1 
once again to process picture element electrode 5 into the desired form 
(FIG. 1A.sub.6). 
The detailed process of the self-alignment method is shown by FIGS. 
1B.sub.1 and 1B.sub.2 in which reference numeral 14 designates a negative 
type photo resist and 15 designates ultraviolet rays (h.multidot..nu.). 
It is noted that the third thin film (or the second electrode) serving also 
as the picture element electrode may be likewise formed by a lift-off 
method using a positive type photo resist. This process is shown in detail 
by FIGS. 1C.sub.1 and 1C.sub.2 wherein reference numeral 140 designates a 
positive type photo resist. In this case, the sequence of forming the 
third thin film (or the second electrode) is reversed in comparison with 
the foregoing method using the negative type photo resist 14, but the same 
result is eventually obtained. In the process of forming the third thin 
layer using a self-alignment method, it is also possible to carry out 
exposure with a photo mask 18 for a pattern of the picture element 
electrode 5 being disposed on the rear surface of substrate 1, as shown in 
FIGS. 1D.sub.1 and 1D.sub.2. This enables reduction in the number of steps 
of the photolithography process, since picture element electrode 5 can be 
formed simultaneously with the non-linear element. 
It should be understood that the greatest advantage resulting from forming 
the third thin film using a self-alignment method is in making it possible 
to stably manufacture elements superior in non-linear characteristics 
without the need of fine alignment during the photolithography process. 
This is attributable to the fact that the non-linear element is formed on 
the side portion of the first thin film layer, and the element size is 
automatically determined by a thickness of the first thin film only with a 
pattern of the third thin film being formed constant. According to the 
present invention, therefore, non-linear characteristics can be improved 
and stabilized and the manufacturing process can be simplified as compared 
with the prior art. Furthermore, use of the self-alignment method is 
advantageous in that there is no need of a fine photolithography 
technique. There is also simplified element configuration, thus resulting 
in high yield, lower cost and high reliability. 
Operation of a non-linear element thus manufactured will now be described 
by referring to the case where it is applied to a liquid crystal display. 
The non-linear element has a resistance value which varies depending on 
voltage as shown in FIG. 2, thus providing non-linear characteristics with 
a current not in conformity with Ohm's law. Accordingly, when a driving 
signal applied to a liquid crystal panel is in such a state where the 
current flows through the non-linear element, i.e., in an ON state, the 
electric field is applied to the crystal liquid layer to be lit up. When 
the driving signal is in such a state where little current flows through 
the non-linear element, i.e., in an OFF state, the electric field applied 
to the liquid crystal layer is so small that it will not be lit up. 
Use of such non-linear characteristics makes it possible to significantly 
improve dynamic driving characteristics of the liquid crystal panel. More 
specifically, while the normalliquid crystal panel is operated at a duty 
as much as about 1/64, the present liquid crystal display incorporating 
the non-linear elements manufactured as described above can be operated at 
duty of 1/500 or less and has a greatly improved display quality. Specific 
examples will now be described. 
EXAMPLE 1 
FIGS. 3A and 3B show the process in accordance with the present invention, 
and FIG. 3C shows a partial plan view of a group of MIM elements in 
accordance with the above process. 
As shown in FIG. 3A, a first electrode 2 of each MIM element is formed on a 
substrate 1 and then processed into a predetermined shape. Next, an 
insulator 4 of the MIM element is formed on the surface of the first 
electrode 2 thereof. Subsequently, a second electrode 5 of the MIM element 
and a transparent element 6 are formed thereon in this order. It is to be 
noted that a film thickness of the second electrode 5 of the MIM element 
is selected to be less than 200 .ANG.. Thereafter, a negative type photo 
resist 14 is formed and a self-alignment method is carried out in which 
the substrate is exposed from behind, as depicted, using ultraviolet rays 
15, with the first electrode 2 of the MIM element acting as a mask. The 
first electrode 2 of the MIM element is generally formed of metals such as 
Al or Ta, s the ultraviolet rays 15 will not transmit therethrough. The 
second electrode 5 is also generally formed of metals such as Al, Ta or Cr 
but has a film thickness less than 200 .ANG., so the ultraviolet rays 15 
transmit therethrough. The transparent electrode 6 is transparent, so the 
ultraviolet rays transmit therethrough. As a result, the front side of the 
substrate except for the part masked by the metal forming the first 
electrode 2 of the MIM element, is exposed to the ultraviolet rays 15. 
Thereafter, the negative photo resist 14 is developed and both the 
transparent electrode 6 and the second electrode 5 of the MIM element are 
removed, thus resulting in the state as shown in FIG. 3B. In other words, 
the second electrode 5 of the MIM element and the transparent electrode 6 
are both left only at a side face portion 16 of the first electrode 2 of 
the MIM element, on the front of which is formed the insulator 4 of the 
MIM element. Next, the negative photo resist 14 is removed and both the 
second electrode 5 of the MIM element and the transparent electrode 6 are 
processed into a predetermined shape as shown in FIG. 3C. At this time, 
the picture element area of the electro-optic device and the length 17 of 
each MIM element are determined. 
Operation of the MIM element thus manufactured will now be described by 
referring to FIG. 4. FIG. 4 shows an equivalent circuit (solid lines) of 
one picture element of the electro-optic device incorporating the MIM 
elements of the present invention in comparison with an equivalent circuit 
(combination of solid lines and broken lines) for a conventional device. 
Insulator 4 would include a static capacitance and a resistance 8. The MIM 
element includes a static capacitance 9 and a non-linear resistance 10. 
Further the liquid crystal layer includes a static capacitance 11 and a 
resistance 12. 
When driving the liquid crystal layer with the MIM element, it is required 
that the non-linear resistance 10 of the MIM element have good non-linear 
characteristics, and that the static capacitance 9 of the MIM element be 
sufficiently smaller than the static capacitance 11 of the liquid crystal 
layer. In the conventional MIM element, the static capacitance 7 of the 
insulator 4 is coupled in parallel to the static capacitance 9 of the MIM 
element. Stated differently, the equivalent capacitance of the MIM element 
is increased and cannot be made sufficiently small as compared with the 
static capacitance of the liquid crystal layer, thus degrading a display 
quality of the electro-optic device. Also, the resistance 8 of the 
insulator 4 is coupled in parallel to the non-linear resistance 10 of the 
MIM element. 
The non-linear resistance 10 of the MIM element has a tendency to increase 
its resistance when lower voltage is applied thereto and to lower its 
resistance when higher voltage is applied thereto. With the resistance 8 
of the insulator 4 being coupled in parallel, therefore, the resistance 
value of the MIM element becomes small when lower voltage is applied 
thereto, and this degrades a display quality of the device. 
On the other hand, according to the present invention, there exists no 
static capacitance coupled to the MIM element in parallel. More 
specifically, the static capacitance serially coupled to the static 
capacitance 11 of the liquid crystal layer is only the static capacitance 
9 of the MIM element. The static capacitance 9 of the MIM element can be 
made sufficiently small as compared with the static capacitance 11 of the 
liquid crystal layer, thereby making it possible to improve a display 
quality of the electro-optic device. Also, there exists no resistance 
coupled to the MIM element in parallel. On this account, it becomes 
possible to effectively utilize such a feature of the MIM element that it 
has high resistance when lower voltage is applied to the non-linear 
resistance and has low resistance when higher voltage is applied thereto. 
Further, since the second electrode 5 of the MIM element and the 
transparent electrode 6 are both present only at the side surface of the 
first electrode 2 of the MIM element on which the insulator 4 of the MIM 
element has been formed, there can be obtained a MIM element superior in 
non-linear characteristics without the need of a fine photolithography 
technique. 
EXAMPLE 2 
FIG. 5A shows the main process of another embodiment in accordance with the 
present invention, and FIG. 5B shows a section of a MIM element 
manufactured with this process. The steps of forming the second electrode 
5 of the MIM element, the transparent electrode 6 and the negative type 
photo resist 14 are the same as those in Example 1. The difference from 
Example 1 is in combined use of a photo mask in the self-alignment method. 
More specifically, as shown in FIG. 5A, a photo mask 18 is disposed on the 
rear surface 1a of substrate 1 and ultraviolet rays 15 are exposed from 
behind. Next, the negative type photo resist 14 is developed and both the 
transparent electrode 6 and the second electrode 5 of the MIM element are 
removed, thus resulting in a structure as shown in FIG. 5B. In other 
words, the MIM element is formed at the side face portion 16 of the first 
electrode 2 of the MIM element on which is formed the insulator 4 of the 
MIM element, and the picture element area of the electro-optic device and 
the length 17 (FIG. 3C) of the MIM element are both determined. Namely, it 
requires just one process to determine the picture element area of the 
electro-optic device and the length of the MIM element. As a result of 
intensive testing conducted by the present inventor, the above process was 
realized by using a projection aligner as a practical exposure unit and 
carrying out alignment exposure with the focus being adjusted to the front 
surface of the substrate. 
EXAMPLE 3 
To form the first metal film layer: Al was vapor-deposited on a Pyrex glass 
substrate by an EB evaporation method to have a film thickness of about 
2000 .ANG.. Next, to obtain a given pattern of the first layer, a positive 
type photo resist was coated on the Al film and it was subjected to the 
normal photolighography process. A PNC solution (mixture solution of 
phosphoric acid, nitric acid and acetic acid) was used for etching Al. 
To form the second insulating film layer: Magnetron sputtering SiO.sub.2 
was carried out with the terminal portion of the first layer pattern being 
masked by a metal foil, to obtain a dense and uniform film of about 500 
.ANG.. 
To form the third ITO film layer: Reactive sputtering with magnetron DC 
sputtering was carried out over the entire surface of the substrate to 
form an ITO film of about 300 .ANG. thickness. Next, a negative type photo 
resist was coated by a spinner to be 1.5 .mu.m thick and a self-alignment 
method was carried out such that the substrate was exposed from the rear 
side thereof with the first Al layer pattern as a mask, to form an 
overlapping portion of the nonlinear element. Finally, a positive type 
photo resist was once again coated in a similar manner and each picture 
element electrode was obtained with the normal photolithography process. 
The electrode substrate thus fabricated was used as one of electrode 
substrates for holding a liquid crystal material therebetween. The above 
electrode was used as a column (or row) electrode, a row (or column) 
electrode was formed on the other electrode substrate and it was driven by 
a voltage averaging method. As a result, there were obtained a 
satisfactory contrast and a wide visual angle even at a duty of 1/500 with 
V-4V driving in which Vo voltage is applied at non-selection of time 
sharing driving and 4Vo voltage is applied at selection thereof. 
EXAMPLE 4 
First metal film layer: Ni 
Second insulating film layer: SiO.sub.2 
Third metal film layer: Al. 
The above materials were used for the respective layers, and a non-linear 
element was fabricated in a similar manner to Example 1 (the first metal 
film layer, Al is formed thereon with magnetron DC sputtering) and the 
same result as that of Example 1 was obtained. 
EXAMPLE 5 
First metal film layer: Cr 
Second insulating film layer: Cr.sub.2 O.sub.3 
Third film layer: ITO. 
The above materials were used for the respective layers, the films of Cr 
and Cr.sub.2 O.sub.3 were formed with continuous magnetron RF sputtering 
under the same vacuum, and the self-alignment method was carried out to 
obtain a non-linear element. This non-linear element was used to form a TN 
type liquid crystal cell which was then driven in a time sharing manner. 
As a consequence, there was obtained the same result as that of Example 3. 
EXAMPLE 6 
First metal film layer: Ta of 4000 .ANG. thickness 
Second insulating film layer: Ta.sub.2 O.sub.5 of 500 .ANG. thickness 
Third metal film layer: Cr of 4000 .ANG. thickness. 
A non-linear element was fabricated in a similar manner to Example 5 and 
the same result as that of Example 3 was obtained. 
EXAMPLE 7 
First metal film layer: Ta 
Second insulating film layer: SiO.sub.2 
Third film: ITO. 
The above materials were used for the respective layers, the films of Ta 
and SiO.sub.2 were formed with continuous magnetron RF sputtering under 
the same vacuum, and a non-linear element was manufactured by a method in 
which a photo mask for the picture element electrode was disposed on the 
rear surface of the substrate at the time of forming the third thin film 
layer, serving also as a transparent picture element electrode, with a 
self-alignment method, while simplifying the process. This non-linear 
element was used to form a TN type liquid crystal cell which was then 
driven in a time sharing manner. As a consequence, there was obtained the 
same result as that of Example 3. 
FIGS. 6A through 6F show alternative embodiments of the manufacturing 
method of the electro-optic device in accordance with the present 
invention. 
More specifically, as shown in FIG. 6A, the electro-optic device of the 
present inventio may be manufactured such that the second electrode 6 of 
the MIM element is formed along the first electrode thereof. 
When viewed from above, the electrodes of the MIM element may be arranged 
as shown in FIGS. 6B and 6C in place of the arrangement as shown in FIG. 
3C. 
In any case, the electrodes constituting the MIM structure may be arranged 
into such configurations as shown in FIGS. 6D, 6E and 6F in which a part 
of the second electrode 5 overlaps the transparent electrode 6. 
FIG. 7 shows an embodiment of a liquid crystal display in which the 
electrode substrate having the MIM structure as shown in FIG. 6A is used 
as one of the electrode substrates for holding a liquid crystal material 
19 therebetween. 
EXAMPLE 8 
A liquid crystal display was structured as shown in FIG. 8. A liquid 
crystal display body P includes substrates P.sub.1, P.sub.2 holding a 
liquid crystal material therebetween, and polarizers P.sub.3, P.sub.4 
arranged on the upper and lower surfaces thereof. Driving voltages as 
shown in FIG. 10 were applied to the electrode on the scanning side and 
the electrode on the signal side from a driving circuit Z, respectively. 
Hereinafter, operation of the liquid crystal display according to the 
present invention will be described in detail by referring to the 
illustrated embodiment. 
FIG. 9 is a block diagram of a circuit showing one example of a display 
embodying the present invention. The circuit includes a liquid crystal 
driving voltage generating circuit 101 which is so arranged that five 
voltage dividing resistors R1, R2, R3, R4 and R5 are serially coupled to a 
voltage source 102 for outputting voltage Eo to bring each picture element 
into an ON state, and an impedance converter is coupled which includes 
operational amplifiers D1, D2, D3 and D4 having their one input terminals 
coupled to joints C1, C2, C3 and C4 between the resistors R1, R2, R3, R4 
and R5 and having their other input terminals coupled to their output 
terminals, thereby dividing the voltage Eo into the following voltages to 
be output, respectively: 
##EQU1## 
where N is the number of scanning lines. The constant K is a value larger 
than 1 which is varied depending on the matrix liquid crystal panel used. 
A scanning electrode driving circuit 103 is so arranged to receive driving 
voltages V0, V1, and V4 from the liquid crystal driving voltage generating 
circuit 101 and a signal from a timing control circuit 104, and to scan in 
sequence scanning electrodes Y1, Y2 . . . Ym of a matrix type liquid 
crystal display panel 105 with the signal from the timing control circuit. 
A signal electrode driving circuit 106 is so arranged to receive voltages 
V0, V2, V3 from the liquid crystal driving voltage generating circuit 101 
and a signal from the timing control circuit 104, and to scan in sequence 
signal electrodes X1, X2 . . . Xn at the given voltage with the signal 
from the timing control circuit 104. 
Operation of the display thus arranged will now be described by referring 
the waveforms shown in FIG. 10. 
When a video signal is input to the timing control circuit 104, the driving 
voltages are supplied from the scanning electrode driving circuit 103 to 
the individual scanning electrodes Y1, Y2 . . . Ym in accordance with 
synchronizing signals in the input signal (I), so that the voltages V5, V0 
are applied to the selected scanning electrodes and the voltages V4, V1 
are applied to the non-selected scanning electrodes. On the other hand, 
the driving voltages are supplied from the signal electrode driving 
circuit 106 to the individual signal electrodes (II), thus applying the 
voltages V0, V5 to the selected signal electrodes and the voltages V2, V3 
tothe non-selected signal electrodes, so that those signal electrodes are 
scanned in sequence. At this time, the alternating voltage having an 
effective value of 
##EQU2## 
is applied to the non-selected picture elements. It is to be noted that 
the driving signals applied to the liquid crystal panel, i.e., driving 
waveform applied to the scanning electrodes, driving waveform applied to 
the signal electrodes as well as driving waveform applied to the liquid 
crystals, are configured as shown in FIG. 10. 
On this account, the panel screen displays thereon an image in which each 
picture element is driven with a contrast corresponding to that instructed 
by the video signal in ratio of 1 to 1, and which is duly ordered in 
gradation. 
The electro-optic device manufactured by the method of the present 
invention was able to provide a satisfactory contrast ratio, even when the 
value of N was selected much smaller than the number of scanning lines. 
In case of driving at 1/500, for example, there was obtained the 
satisfactory contrast ratio even with the value of N set to 16 in place of 
500, the value of K set to 1 and use of V-5V driving voltage (i.e., 
voltage averaging method in which 5Vo voltage is applied when selected and 
Vo voltage is applied when non-selected). 
EXAMPLE 9 
A liquid crystal display body constituting the liquid crystal display of 
the present invention was structured as shown in FIGS. 11A through 11D. 
FIG. 11A shows an embodiment where a direction of LP10 of orientation 
treatment of an upper substrate P1 (orientation treatment was carried out 
by rubbing) is set in the direction of the corresponding arrow, a directio 
LP20 of orientation treatment of a lower substrate P2 is set in the 
direction of the corresponding arrow, and a crossing angle .theta.1 
therebetween is set to 90.degree.. A direction LP30 of polarizing axis of 
the upper polarizer P3 (the polarizing axis is perpendicular to the 
absorbing axis) is in parallel to the direction LP20 of orientation 
treatment, and a direction LP40 of polarizing axis of the lower polarizer 
P4 is in parallel to the directio LP10 of orientation treatment. 
FIG. 11B shows another embodiment that the crossing angle .theta.1 between 
the directions of orientation treatment is set from 80.degree. to 
100.degree., and the polarizing axes LP30, LP40 are both in parallel to 
the direction LP10 of orientation treatment. 
Furthermore, FIG. 11C shows still another embodiment where the crossing 
angle .theta.1 between the directions of orientation treatment and a 
crossing angle .theta.2 between the polarizing axes are both set from 
80.degree. to 100.degree., the direction LP40 of polarizing axis is 
substantially in parallel to the direction LP10 of orientation treatment, 
and the direction LP30 of polarizing axis is substantially in parallel to 
the direction LP20 of orientation treatment. 
FIG. 11D shows still another embodiment where the crossing angle .theta.1 
between the directios LP10 and LP20 of orientation treatment is set from 
80.degree. to 100.degree., and the polarizing axes LP30, LP40 are both 
substantially in parallel to the direction LP20 of orientation treatment. 
The viewing direction of these display bodies is one from below to above as 
indicated by arrow L. 
It is also possible to manufacture the display body in such a manner that 
the direction LP10 of orientation treatment of the upper substrate P1 is 
reversed relative to the direction LP20 of orientation treatment shown in 
FIGS. 11A through 11D, the direction LP20 of orientation treatment of the 
lower substrate P2 is reversed relative to the direction LP10 or 
orientation treatment shown in FIGS. 11A through 11D, and the polarizing 
axes of the upper and lower axes P2, P3 are aligned with the directions or 
orientation similar to FIGS. 11A through 11D, with the viewing direction 
being set to be one from below to above. 
EXAMPLE 10 
A liquid crystal display was fabricated by laminating a reflector onto the 
lower polarizer P4 of the liquid crystal display body P shown in FIG. 8. 
EXAMPLE 11 
A liquid crystal display of transmission type was fabricated by 
irradicating a back light to the liquid crystal display body P shown in 
FIG. 8 from below. 
A beam of radiation exposed from the rear of the substrate for the 
self-alignment is preferably ultraviolet radiation, buy may be of infrared 
radiation, visible radiation, an electron beam or a laser beam. 
In the MIM-type electro-optic device, the smaller the capacitance C.sub.MIM 
of a non-linear element is in comparison with the capacitance C.sub.LC of 
a liquid crystal layer on the picture element electrode, the more 
effectively the driving voltage is applied to the non-linear element. The 
ratio of C.sub.LC /C.sub.MIM is required to be larger than 1, preferably 
above 3 and ideally above 8-10. According to the manufacturing method of 
the present invention, it is easy to achieve the value of C.sub.LC 
/C.sub.MIM larger than 1 and this imposes good influence upon utilization 
of non-linear characteristics. 
It is to be noted that, in the present invention, the electrode referred to 
as a first electrode indicates the metal electrode on the terminal 
electrode side out of the MIM electrodes, and the metal electrode on the 
picture element side is referred to as a second electrode. 
An electrode substrate material may be of glass, plastic or any other 
materials which have a sufficient transmission factor. In case the liquid 
crystal display according to the manufacturing method of the present 
invention is used as a reflection type, an insulating layer may be formed 
on a thin metal sheet having a good reflection characteristic to thereby 
provide an electrode substrate. 
In case of a self-alignment method with the first electrode as a reference 
electrode, a first electrode material may be of any metal, but preferably 
Al, Ni, Cr or Ta in order to achieve non-linear characteristics. A 
thickness of the first electrode is preferably in the range of about 1000 
.ANG.-1.mu.. In the case of Al, a thickness of about 2000 .ANG. is 
preferable and, in the case of Ta, a range of 3000 .ANG.-6000 .ANG. is 
preferable. 
A second electrode material in case of forming the second electrode with 
the first electrode as a reference electrode using a self-alignment 
method, may be of almost any metals such as Cr, Al or Nichrome. As an 
alternative, alloys such as NiCr may be also used. A thickness of the 
metal used is preferably less than 200 .ANG., more preferably less than 
100 .ANG., in order to effectively transmit a beam of radiation for 
exposure. A more thin metal layer is preferable, but it becomes hard to 
form a continuous film when it is extremely thin. According to the latest 
technology, a lower limit of thickness is about 10 .ANG.. In practice, a 
thickness of 40-60 .ANG. is preferable. 
In case of forming the first electrode on the second electrode by a 
self-alignment method with the latter as a reference electrode, the 
above-mentioned first and second electrodes may be reversed in their 
constructions such that the first electrode film is formed to be thin 
enough to effectively transmit a beam of radiation for exposure. 
The second electrode is further electrically coupled to a picture element 
electrode. The second electrode and the picture element electrode may be 
electrically coupled to each other, so that both electrodes may be 
overlapped in a laminated form just at the portions thereof, or the entire 
picture element portion may be structured such that the picture element 
electrode is completely eliminated over the second electrode. As an 
alternative, the second electrode may serve also as a picture element 
electrode directly. In this case, the second electrode may be formed of 
ITO, SnO.sub.2, ZnO, or other materials which have a sufficient 
transmission factor. In case of using ITO, a preferable thickness is from 
100 .ANG.-2000 .ANG., more preferably from 200 .ANG.-800 .ANG.. This also 
applies in the case of SnO.sub.2. Of course, the second electrode and the 
picture element electrode may be structured as separate elements from each 
other. The mixture of indium oxide and tin oxide may be used as ITO. 
The insulator may be of metal oxides such as SiO.sub.2, Cr.sub.2 O.sub.5, 
Ta.sub.2 O.sub.5, and the like. 
As an example, the first electrode of the MIM element may be of Ta, the 
second electrode may be of Ta.sub.2 O.sub.5, and the insulator may be of 
Cr. In this case, it is preferable that Ta has a thickness of 3000-5000 
.ANG., that TA.sub.2 O.sub.5 has a thickness of 300-600 .ANG. and that Cr 
have a thickness of 600-800 .ANG.. 
Furthermore, a lead electrode coupling the first electrodes of the MIM 
elements is preferably formed of a metal film having low resistance. As an 
alternative, the first electrode may serve also as a lead electrode. 
As fully described herein, according to the present invention, since a 
negative or positive type photo resist is employed and a self-alignment 
method is carried out in which the substrate is exposed from the rear 
side, with the first thin layer of a non-linear element as a mask, it 
becomes possible to eliminate the need of a fine photolithography 
technique, to obtain a non-linear element superior in non-linear 
characteristics since the element is formed just at the side face portion 
of the first thin film layer, and to provide a liquid crystal display of 
large capacity which has a good display quality. 
The number of steps necessary for the photolithography can be reduced with 
combined use of a photo mask in the above self-alignment method. Further, 
the number of steps necessary to form the thin film can be also reduced by 
forming both the second insulating film layer and the third thin film 
layer of the non-linear element in the same vacuum, and by arranging the 
third thin film layer to serve also as a transparent picture element 
electrode. As a result, it becomes possible to remarkably simplify the 
manufacturing process, achieve can improved yield and lower the cost, thus 
providing a less expensive liquid crystal display of large capacity. 
Consequently, the present invention is particularly effective in a liquid 
crystal display used for computer terminals and personal computers which 
require a large screen display of large capacity. 
It will thus be seen that the objects set forth above, among those made 
apparent from the preceding description, are efficiently attained and, 
since certain changes may be made in carrying out the above method and in 
the article set forth without departing from the spirit and scope of the 
invention, it is intended that all matter contained in the above 
description and shown in the accompanying drawings shall be interpreted as 
illustrative and not in a limiting sense. 
It is also to be understood that the following claims are intended to cover 
all of the generic and specific features of the invention herein described 
and all statements of the scope of the invention which, as a matter of 
language, might be said to fall therebetween.