KR20030044388A - Reflective type liquid crystal display and manufacturing method of the same - Google Patents

Abstract

PURPOSE: A reflective liquid crystal display device and a method for fabricating the same are provided to keep the flat plate state of a transparent substrate during the assembling procedure of a semiconductor wafer and the transparent substrate by using the surface tension of liquid crystal, thereby preventing the fringe caused by the deformation of the transparent substrate. CONSTITUTION: A method for fabricating a reflective liquid crystal display device includes the steps of printing a sealant on a transparent substrate, dropping liquid crystal to spaces defined by the sealant with a liquid crystal dropping unit, aligning a semiconductor wafer on the transparent substrate, assembling the aligned semiconductor wafer and the transparent substrate integrally by pressing, and curing the sealant.

Description

Reflective Liquid Crystal Display and Manufacturing Method thereof {REFLECTIVE TYPE LIQUID CRYSTAL DISPLAY AND MANUFACTURING METHOD OF THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to reflective liquid crystal displays, and more particularly, to reflective liquid crystal displays called liquid crystal on silicon (LCOS), which form liquid crystal cells on semiconductor substrates. .

Unlike conventional liquid crystal displays, the LCOS is a liquid crystal material injected between a semiconductor substrate and a transparent substrate. The LCOS is highly integrated with elements and switching circuits of each pixel to realize a high resolution of XGA or higher in a small size of about 1 inch. In recent years, the display of the projection system has attracted attention.

Conventional LCOS fabrication forms about 50 LCOS semiconductor substrates together on a semiconductor wafer, and prints a sealant giving a cell gap with the semiconductor substrate on a transparent substrate corresponding to the semiconductor substrate, and uses an aligner on the semiconductor wafer. After aligning the transparent substrate, and pressurizing at a predetermined pressure, the step of assembling the semiconductor wafer and the transparent substrate integrally.

Here, as shown in FIG. 1, the sealant 1 is formed on the transparent substrate 3 except for the liquid crystal injection hole 1a into which the liquid crystal is to be injected, and the semiconductor wafer and the transparent substrate assembled as described above are cut and individually. Are separated into LCOS panels. After injecting liquid crystal into each LCOS panel through the liquid crystal inlet, the LCOS panel is completed by sealing the liquid crystal inlet.

The LCOS manufactured as described above has a small cell gap of about 1 μm, unlike a conventional liquid crystal display maintaining a cell gap of about 2 to 5 μm, and in particular, the LCOS maintains a cell gap with only an inner sealant.

As the LCOS maintains a small cell gap as described above, when the semiconductor wafer and the transparent substrate are pressurized and assembled together, the transparent substrate made of glass is curved toward the inside of the LCOS panel without maintaining a flat state due to pressure. Contact with the wafer.

The deformation of the transparent substrate is not restored even after the liquid crystal is injected into the LCOS panel, and as shown in FIG. 2, the fringes in which the stripes are repeated due to the interference of light and diffraction caused by the deformation of the transparent substrate 3. ) Causes the phenomenon.

Moreover, LCOS is mainly applied to a projection system that magnifies and projects the image implemented by the LCOS using an optical system, thereby greatly reducing display characteristics such as contrast and brightness of the projection screen. This requires the development of LCOS panels and manufacturing methods that do not cause fringes.

On the other hand, in the conventional LCOS manufacturing, when the sealant is printed on the transparent substrate, the sealant is printed except for the liquid crystal injection hole for the liquid crystal injection, and there is a process trouble to seal the liquid crystal injection hole after the liquid crystal injection.

Therefore, the present invention is to solve the above problems, an object of the present invention is to assemble the transparent substrate integrally with the semiconductor wafer while maintaining the transparent substrate in a flat state to prevent the fringe phenomenon caused by the deformation of the transparent substrate The present invention provides a reflective liquid crystal display and a method of manufacturing the same.

Another object of the present invention is to provide a reflective liquid crystal display capable of shortening the process and improving process yield by simplifying the liquid crystal injection process such as eliminating the liquid crystal injection hole sealing process and a method of manufacturing the same.

1 is a schematic diagram of a reflective liquid crystal display according to the prior art;

2 is a schematic view for explaining a fringe phenomenon.

3 is a plan view of a reflective liquid crystal display according to the present invention;

4 is a cross-sectional view taken along line II of FIG. 3.

5 is a process flowchart of the method of manufacturing a reflective liquid crystal display according to the present invention.

6 to 9 are schematic views at each step for explaining a method for manufacturing a reflective liquid crystal display according to the present invention.

In order to achieve the above object, the present invention,

A semiconductor substrate having a plurality of semiconductor integrated circuits, a transparent substrate disposed opposite to the semiconductor substrate and forming a plurality of transparent electrodes on one surface of the semiconductor substrate, and formed thereon while being electrically connected to the semiconductor integrated circuit; A reflective liquid crystal display comprising a plurality of reflective electrodes constituting a pixel in combination with the transparent electrode, a sealant surrounding edges of the semiconductor substrate and the transparent substrate, and a liquid crystal layer disposed between the semiconductor substrate and the transparent substrate. To provide.

In addition, the present invention, in order to achieve the above object,

Printing a sealant on the transparent substrate, dropping the liquid crystal into a space partitioned by the sealant using a liquid crystal drop device, aligning the semiconductor substrate on the transparent substrate, and aligning the aligned transparent substrate and the semiconductor It provides a method of manufacturing a reflective liquid crystal display comprising the step of assembling the substrate integrally by pressing the substrate, and curing the sealant.

Optionally, a plurality of sealants corresponding to a plurality of LCOS panels are printed on the transparent substrate, aligned and assembled integrally with a semiconductor wafer comprising a plurality of semiconductor substrates, and then the assembled transparent substrate and the semiconductor wafer are cut and individually Can be separated into LCOS panels.

Thus, according to the present invention, since the transparent substrate maintains the flat state during the assembly process of the semiconductor wafer and the transparent substrate due to the surface tension of the liquid crystal, the fringe phenomenon due to the deformation of the transparent substrate is effectively prevented, and the liquid crystal for each separated LCOS panel Since the step of injecting and sealing the liquid crystal injection hole may be omitted, the liquid crystal injection process may be simplified.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a plan view of a reflective liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along line II of FIG.

As shown, the reflective liquid crystal display 2 (hereinafter referred to as "LCOS" for convenience) is opposed to the semiconductor substrate 6 and the semiconductor substrate 6 including a plurality of semiconductor integrated circuits 4 as switching circuits. The transparent substrate 8 disposed, the sealant 10 surrounding the edges of the semiconductor substrate 6 and the transparent substrate 8, and the liquid crystal layer 12 positioned between the semiconductor substrate 6 and the transparent substrate 8. ).

A transparent electrode 14, such as indium tin oxide, is formed on one surface of the transparent substrate 8 facing the liquid crystal layer 12, and the semiconductor substrate 6 facing the transparent substrate 8 may be formed. On one surface, a reflective electrode 16 such as an aluminum film is formed for each pixel, and the transparent electrode 14 and the reflective electrode 16 are combined to form a pixel, and each function as a common electrode and a pixel electrode.

At this time, an alignment film (not shown) is formed on the surfaces of each of the transparent electrode 14 and the reflective electrode 16 to align the liquid crystal molecules in a predetermined direction, and the LCOS 2 has a sealant 10 of approximately 1 μm. Maintain cell gap.

In particular, the reflective electrode 16 is electrically connected to the semiconductor integrated circuit 4 provided for each pixel. More specifically, the semiconductor integrated circuit 4 may include a source 18 and a drain 20 formed in the semiconductor substrate 6. And a gate electrode 22 positioned therebetween.

The drain 20 is electrically connected to the reflective electrode 16 by the connection electrode 24, and a capacitor 26 is disposed adjacent to the gate electrode 22, and the gate electrode 22 and the connection electrode ( 24 and capacitor 26 are separated from each other by insulating layer 28.

Thus, when the semiconductor integrated circuit 4 having the above-described configuration applies a switching signal to the reflective electrode 16, the reflective electrode 16 rearranges the liquid crystal molecules together with the transparent electrode 14, thereby improving the light transmittance for each pixel. By changing, a predetermined image is realized.

Here, the LCOS 2 according to the present embodiment has a structure in which the sealant 10 surrounds the edges of the semiconductor substrate 6 and the transparent substrate 8 without a liquid crystal injection hole and a sealant for sealing the liquid crystal injection hole. . As a result, sealant printing is more easily performed, and the liquid crystal injection hole sealing process is omitted, thereby simplifying the liquid crystal injection process.

In addition, the present embodiment can easily produce an LCOS panel that does not cause fringe phenomenon through the LCOS manufacturing method described below, and FIG. 5 shows a process sequence of the LCOS manufacturing method according to the embodiment of the present invention. 6 to 9 schematically illustrate the steps of the LCOS manufacturing method according to the embodiment of the present invention.

First, as shown in FIG. 6, the transparent substrate 8 which consists of glass is prepared, and the sealant 10 corresponding to many LCOS panels is screen-printed to this transparent substrate 8 by predetermined thickness. The sealant 10 is formed to surround the edge of each LCOS panel without the liquid crystal injection hole, and partitions a space in which the liquid crystal is to be positioned on the transparent substrate 6.

Next, a predetermined amount of liquid crystal 12 is dropped into the space partitioned by the sealant 10 using the liquid crystal drop device 32 including the syringe 30. The liquid crystal 12 dropping moves the syringe 30 or the transparent substrate 8 sequentially to the individual LCOS panels, or as shown in FIG. 7, the liquid crystal drop device 32 corresponds to each LCOS panel. A plurality of syringes 30 can be provided so that liquid crystal drops can be made simultaneously to all LCOS panels.

The amount of liquid crystal injected at this time is the same for all LCOS panels, and as shown in FIG. 8, the liquid crystal dropped so that the volume of the dropped liquid crystal 12 is substantially the same as the volume of the space partitioned by the sealant 10. It is desirable to accurately control the amount.

That is, when the volume of the liquid crystal 12 dropped as shown by the dotted line is smaller than the volume of the space to fill the space, an air layer is formed inside the LCOS when the transparent substrate 8 and the semiconductor wafer 34 are aligned. Causes a failure of the LCOS panel.

In addition, when the volume of the dropped liquid crystal 12 is larger than the volume of the space to form a convex surface as shown by the chain line, the liquid crystal 12 is outward when the transparent substrate 8 and the semiconductor wafer 34 are aligned. Not only is it wasted and wasted, it can cause unintentional contamination by the liquid crystal flowing outward.

As such, the liquid crystal 12 is dropped into the space surrounded by the sealant 10, and then the semiconductor wafer 34 is aligned on the transparent substrate 8, as shown in FIG. 9, and the aligned transparent substrate 8 is aligned with the transparent substrate 8. The semiconductor wafer 34 is mounted on the assembly jig 36. Through the above process, the semiconductor wafer 34 and the transparent substrate 8 are integrally aligned with the liquid crystal layer 12 therebetween.

Next, the aligned semiconductor wafer 34 and the transparent substrate 8 are pressed together to be integrally assembled. To this end, for example, the assembly jig 36 in which the semiconductor wafer 34 and the transparent substrate 8 are aligned is placed inside a pressurization pack (not shown), and the pressurization pack is connected to a vacuum chamber to have an interior of approximately 1 kg _f / cm. ^After the pressure is about ² , the pressure pack inlet is sealed using a known packing device.

As a result, the transparent substrate 8 and the semiconductor wafer 34 mounted on the assembly jig 36 are pressed by the pressure inside the pressurization pack, and through the above press, the transparent substrate 8 and the semiconductor wafer 34 are approximately 1. The cell gap of about μm is maintained.

Then, the assembled transparent substrate 8 and the semiconductor wafer 34 are put into an oven at approximately 130 ° C. for about 1 hour to cure the sealant 10 to complete the assembly of the transparent substrate 8 and the semiconductor wafer 34. do.

In the above assembly process, since the liquid crystal layer 12 is positioned between the semiconductor wafer 34 and the transparent substrate 8 in this embodiment, even if the transparent substrate 8 is pressed to the above-mentioned pressure, the surface tension of the liquid crystal material As a result, the transparent substrate 8 can be maintained in a flat state without being deformed, so that the phenomenon of bending toward the semiconductor wafer 34 can be effectively prevented.

Finally, the transparent substrate 8 and the semiconductor wafer 34 are separated from the pressure pack and the assembly jig 36, and the transparent substrate 8 and the semiconductor wafer 34 are individually separated using a cutter not shown. LCOS fabrication is completed by separating it into LCOS panels.

As described above, after the liquid crystal 12 is dropped in this embodiment, the semiconductor wafer 34 and the transparent substrate 8 are assembled, thereby effectively suppressing the fringe phenomenon caused by the deformation of the transparent substrate 8, and thus, individual LCOS panels. Since the process of injecting the liquid crystal into the liquid crystal injection hole may be omitted, the liquid crystal injection process may be simplified.

Meanwhile, in the above, the process of assembling the transparent substrate and the semiconductor wafer and then separating them into individual LCOS panels has been described as an example. However, in the present invention, after preparing the individual transparent substrate and the semiconductor substrate, the transparent substrate and the semiconductor substrate are described. The same applies to the process of assembling the above-described method.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

Thus, according to the present invention, since the transparent substrate maintains the flat state during the assembly process of the semiconductor wafer and the transparent substrate due to the surface tension of the liquid crystal, the fringe phenomenon due to the deformation of the transparent substrate is effectively prevented, and the liquid crystal for each separated LCOS panel Since the step of injecting and sealing the liquid crystal injection hole may be omitted, the manufacturing time of the display may be shortened and the manufacturing yield may be improved.

Claims (8)

A semiconductor substrate having a plurality of semiconductor integrated circuits; A transparent substrate disposed to face the semiconductor substrate and forming a plurality of transparent electrodes on one surface of the semiconductor substrate; A plurality of reflective electrodes electrically connected to the semiconductor integrated circuit and formed thereon to form a pixel in combination with the transparent electrode; A sealant surrounding edges of the semiconductor substrate and the transparent substrate; And And a liquid crystal layer disposed between the semiconductor substrate and the transparent substrate. Printing a sealant on a transparent substrate; Dropping the liquid crystal into a space partitioned by the sealant using a liquid crystal drop device; Aligning a semiconductor substrate on the transparent substrate; Pressing the aligned transparent substrate and the semiconductor substrate and assembling them integrally; And And curing the sealant. The method of claim 2, And the printing of the sealant comprises printing a plurality of sealants on a transparent substrate corresponding to the plurality of LCOS panels. The method of claim 2, And the step of aligning and assembling the transparent substrate and the semiconductor substrate comprises integrally aligning and assembling a semiconductor wafer including the transparent substrate and a plurality of semiconductor substrates. The method of claim 4, wherein And after the sealant curing step, cutting the assembled semiconductor wafer and the transparent substrate into separate LCOS panels. The method of claim 2, The liquid crystal dropping device includes a syringe, and the dropping of the liquid crystal moves the syringe or the transparent substrate to continuously drop the liquid crystal into a space partitioned by individual sealants. The method of claim 2, And the liquid crystal drop device comprises a plurality of syringes, and wherein dropping the liquid crystal simultaneously drops the liquid crystal into a space partitioned by individual sealants using the syringe. The method of claim 2, Aligning and assembling the transparent substrate and the semiconductor substrate may include aligning the transparent substrate and the semiconductor substrate with an assembly jig, placing the assembly jig inside the pressure pack, connecting the pressure pack with a vacuum chamber, and then The manufacturing method of the reflection type liquid crystal display which seals an inlet and presses a transparent substrate and a semiconductor substrate by the internal pressure of a pressure pack.