JPS6030956B2 - Method for manufacturing color image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color image display device constructed by combining a liquid crystal and a semiconductor integrated circuit, and in particular to a transmissive color image display device obtained using the transparent substrate. The present invention aims to form a predetermined coloring material on the picture element in a self-aligning manner, and to selectively form a light shielding film using this coloring material as a mask.

An example of a conventional image display device constructed using a liquid crystal and a MOS transistor is shown in FIG.

A unit picture element is composed of a MOS transistor 1, a storage capacitor 2, and a liquid crystal cell 3, and its operating principle is as follows. For example, when a gate signal is applied to zi, transistor 1 is turned on, and the video signal passes from yj to transistor 1 and charges capacitor 2. When the gate signal disappears, the charge stored in the capacitor 2 applies a voltage to the liquid crystal cell 3, so the liquid crystal cell 3 changes the phase transition or the magnitude of dynamic scattering according to the voltage and passes through the liquid crystal cell 3. The light can continue to be modulated by the signal voltage. The charge stored in capacitor 2 is transferred to transistor 1 until the next gate pulse is applied.
Since leakage occurs through the OFF resistance of the transistor and the resistance of the liquid crystal cell, the characteristics required of the transistor and liquid crystal are quite strict.For example, if capacitor 2 is set to several PF, the leakage current of transistor 1 and liquid crystal cell 3 must be less than lnA. It is not possible to apply this device to television. As shown in FIG. 1, it is possible to construct a television by arranging unit picture elements in a matrix and scanning them in the z and y directions.

In that case, a so-called quenching operation is required, in which an alternating electric field is applied to the liquid crystal to forcibly relax the dynamic scattering, and then a new video signal is read in, but the details are unnecessary here and will be omitted. . FIG. 2 shows a cross-sectional view of the unit picture element shown in FIG. 1 integrated into an integrated circuit.
Although a transmission type image display device incorporating an aluminum gate transistor on a sapphire substrate 17 will be described here, the same applies to a polycrystalline silicon gate transistor. The transistor 1 consists of a drain or source 4, a channel portion 5, a source or drain 6, 7 is an aluminum gate, and 8 is a gate oxide film.

Reference numeral 9 denotes a silicon oxide film for protecting the surface of the transistor, and is an insulating material covering the parts other than the first picture element, for example, silicon oxide or the like is most suitable.

12 is an insulator made of a transparent substance, and the transparent electrode 11
, 13 form a capacitor.

The transparent electrode may be formed by depositing, for example, S2,1403 or the like. 16 is a glass plate, and 15 is a transparent electrode formed on 16.

A liquid crystal 14 fills the space between the integrated circuit on the sapphire substrate 17 and the transparent electrode 15, and together with the transparent electrode 13 forms the liquid crystal cell 3.

The light 18 incident from below the sapphire substrate 17 is appropriately scattered or subjected to phase inversion by the liquid crystal cell 3, so that it functions as a transmission type image display device. Third
The figure is a top plan view of FIG. The size is chosen to be 75 m x 100 m.

As is well known, in order to construct a color image display device, it is necessary to appropriately arrange the three primary colors of light, namely R, G, and B, on picture elements. Must be divided. In this case, it is necessary to apply a predetermined coloring material on the main surface of the glass plate 16 in each row of R, G, and B rows, preferably on each picture element. However, it is difficult to reduce the thickness of the glass plate 16 to 0.1 skin or less because the larger the number of picture elements, the larger the area of the display device, and also because of the depth of focus of the lens. It is extremely difficult to perform mask alignment to leave a predetermined coloring material on the pattern. Moreover, special processes such as infrared alignment are not preferable because they significantly lower the yield. Further, in the configuration shown in FIG. 2, the light 18 incident from the sapphire substrate 17 causes leakage current generation in the MOS transistor.

Therefore, in the present invention, the pixel pattern is transferred onto the glass plate 16 in a self-aligned manner, for example, according to the wiring pattern of an integrated circuit within the display device, thereby providing a method for manufacturing a high-brightness color image display device with extremely high productivity. A detailed explanation will be given in FIGS. 4 to 6.

4 to 6 show a method of manufacturing a color image display device according to an embodiment of the present invention. Items that are the same as those in Figure 2 are given the same numbers. As shown in FIG. 4a, a glass plate 16 on which a transparent electrode 15 is attached and a sapphire substrate 17 in which an integrated circuit is installed are brought into close contact and filled with liquid crystal 14.
A transparent substance such as silicon oxide 21 is applied over the entire surface of the photoresist 6, and a negative photosensitive resin (resist) 22 is further applied. Then, when the ultraviolet rays 23 are irradiated from below the sapphire substrate 17 for exposure and development, the capacitors and liquid crystal cells that make up the picture elements are all transparent materials as mentioned above, so first the areas corresponding to the two picture elements are exposed. The resist can be left in locations corresponding to areas where the metal interconnections 4', 6' of the integrated circuit are not present. That is, a resist pattern can be formed in a region including the transparent electrode by exposing the metal wiring pattern of the integrated circuit in the device as a mask.
The resist left in this way is used as a mask as shown in Fig. 4b.
As shown in FIG. 3, the silicon oxide 21 is selectively patterned by etching to form an oxide film pattern 21'. After this, as shown in FIG. 4b, the predetermined coloring material can be deposited only on the area corresponding to the picture element using the step 21' as a mark for mask alignment, and the coloring material pattern 2
4 can be formed. This method is particularly effective when the transmittance of the colorant is low. According to the above method, a pattern that serves as a mark for forming a coloring material pattern for coloring is created in a self-aligned manner using the already formed metal wiring pattern of an integrated circuit by exposing the back side of the sapphire substrate. It is easy to form, and a predetermined coloring material pattern can be easily formed using this pattern, making it a preferred method for coloring.

FIG. 5 is a sectional view showing another embodiment of the present invention.
Forming a coloring material directly on the glass 16 as shown in Figure a,
Further, for example, a photosensitive resin is formed thereon and exposed to light from the back side of the sapphire substrate 17 as in the case of FIG.
At this time, since the coloring material is semitransparent, only the light that has passed through the transparent electrodes 11 and 13 excluding the metal wiring portion reaches the photosensitive resin through the coloring material. After this exposure, a development process is performed to form the photosensitive resin pattern 25 that serves as the aforementioned mark.The coloring material is then selectively removed using this pattern 25 as a reference to form a reference pattern 26 of the coloring material. Afterwards, the remaining resin pattern 25 can be removed and a coloring material pattern 26' can be easily formed from the pattern 26. In this embodiment, the pattern 26 as a mark for forming the coloring material pattern is formed using sapphire. This is done by exposing from the back side of the substrate 17, and then patterning is performed again using the pattern 26 as a reference for mask alignment.
As shown in FIG. b, a predetermined coloring material pattern 26' is left only on areas corresponding to picture elements.

In this way, the R coloring material is first applied and then the G coloring material is applied.
, B can be applied to color the picture elements of an image display device that combines a liquid crystal and an integrated circuit. This method also allows the standard of the coloring material pattern to be easily and accurately formed in a self-aligning manner as in FIG. 4. Next, a method of forming a light shielding film using the colorant pattern and transparent electrode formed by the above method will be described.

That is, as shown in FIG.
After the coating 6' is completed, an anti-reflection film 27 made of a non-reflective and opaque material is formed under observation.

Here, a substantially logical image surface is obtained, and unnecessary light does not leak from the back surface of the image display device. However, strictly speaking, it is desirable to form a shield on the back surface to block the pn junction from light. Therefore, after forming the antireflection film 27, a transparent substance is applied to the back surface of the sapphire substrate 17, and a positive resist is applied to the entire surface, and the patterns 26' and 27 on the glass slope are formed by exposing the glass plate 16 to light from above. A transparent material 28 is selectively formed by transfer, and a shielding film 29 made of a metal film or the like can be selectively formed using the step 28 as a reference for mask alignment. The presence of this film 29 makes it possible to provide strong light from below the sapphire substrate 17, resulting in a color image display device with high brightness. Next, a more excellent method for producing this shielding film will be explained.

The purpose of the method described below is to make the formation of the shielding film extremely easy. First, the antireflection film 27
After forming, a negative resist is applied to the back side of the sapphire substrate 17 as shown in FIG. . Next, an opaque film 31 such as a metal film is formed on the entire back surface of the substrate 17. Thereafter, when the resist film 30 is removed, the opaque film on the resist film 30 is also removed (lift-off effect). However, in order for this lift-off effect to work effectively, the thickness of the resist film 30 must be greater than the thickness of the opaque film 31. FIG. 7b shows the light shielding film 31 formed in this manner. As described above, according to the present invention, the pattern of an integrated circuit can be transferred onto the front glass of an image display device in a self-aligning manner by exposure from the back side, so it is extremely easy to form a coloring material for coloring under observation. It becomes reliable, and the utilization efficiency and separation of picture elements becomes ideal.

Furthermore, after forming the antireflection film, the formation of a shielding film that shields the pn junction and the transistor from the light source can be accomplished by adding a very simple process, and a mask alignment process is not necessary. Note that the present invention is not limited to sapphire as a transparent substrate, nor is it limited to silicon as a semiconductor, and as long as the band gap is small and opaque to ultraviolet rays, 0- or m-V A compound semiconductor may also be used.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a color image display device obtained by combining a conventional liquid crystal and a semiconductor integrated circuit, Fig. 2 is a cross-sectional view of the main part of the device, Fig. 3 is a plan view of the main part of the device, and Fig. 3 is a plan view of the main part of the device. Figure 4a,
5b is a process sectional view showing the formation of a coloring material according to an embodiment of the present invention, FIGS. 5a and 5b are process sectional views of other embodiments, and FIG. A cross-sectional view showing
FIGS. 7a and 7b are cross-sectional views showing the formation of a permeation prevention film according to the present invention. DESCRIPTION OF SYMBOLS 1... MOS type transistor, 2... Storage capacitor, 3... Liquid crystal cell, 17... Sapphire substrate, 20... Supply element, 22, 30...・Photosensitive resin, 21'... Sipi pattern, 24, 26'...
... Coloring material pattern, 25 ... Photosensitive resin pattern, 27 ... Antireflection film, 29, 31 ...
Transmission prevention membrane. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6' Figure 7

Claims (1)

[Claims] 1. After forming a metal wiring pattern connecting a capacitor made of a first transparent electrode, a MOS transistor, and a metal wiring pattern connecting the first transparent electrode and the MOS transistor on one main surface of a transparent substrate, A liquid crystal cell is formed with the two transparent electrodes by filling a space between one main surface of a glass plate having a second transparent electrode formed on one main surface and the transparent substrate, and forming a liquid crystal cell with the two transparent electrodes. a step of depositing a transparent substance on the other main surface of the glass plate;
a step of applying a photosensitive resin onto the transparent material; a step of exposing the transparent substrate to ultraviolet light from above the other main surface to form a photosensitive resin pattern corresponding to the metal wiring pattern; selectively leaving the transparent substance in a region corresponding to the first transparent electrode using a photosensitive resin pattern as a mask; A method of manufacturing a color image display device, comprising the step of forming a predetermined coloring material pattern on the other main surface of the corresponding glass plate. 2. After forming a metal wiring pattern on one main surface of the transparent substrate to connect a capacitor made of a first transparent electrode, a MOS transistor, and a metal wiring pattern connecting the first transparent electrode and the MOS transistor, a metal wiring pattern is formed on one main surface of the transparent substrate. A liquid crystal is filled between one main surface of the glass plate on which two transparent electrodes are adhered and the transparent substrate to form a liquid crystal cell with the two transparent electrodes, and the other main surface of the glass plate is filled with liquid crystal. a step of depositing a transparent substance on the surface;
a step of applying a photosensitive resin onto the transparent material; a step of exposing the transparent substrate to ultraviolet irradiation from above the other main surface to form a photosensitive resin pattern corresponding to the metal wiring pattern; selectively leaving the transparent substance in a region corresponding to the first transparent electrode using the photosensitive resin pattern as a mask; and forming the first transparent electrode including the selectively left transparent substance. forming a predetermined coloring material pattern on the other main surface of the glass plate corresponding to the coloring material pattern; forming an antireflection film on the other main surface of the glass plate excluding the coloring material pattern; Applying a negative photosensitive resin on the other main surface of the substrate, and exposing the glass plate to ultraviolet rays from above the other main surface to obtain a negative photosensitive resin corresponding to the coloring material pattern. A step of forming a resin pattern on the other main surface of the transparent substrate, and after coating the entire surface with an opaque material, removing the negative photosensitive resin pattern and removing the opaque material on the negative photosensitive resin pattern. and forming a light shielding film corresponding to the coloring material pattern on the other main surface of the transparent substrate.