JP3008032B2 - Semiconductor device for light valve substrate and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat light valve device used for a direct-view display device or a projection display device, and more particularly to a switch matrix liquid crystal panel. More specifically, the present invention relates to a semiconductor device for a light valve substrate which is integrated as a liquid crystal panel with a liquid crystal layer interposed therebetween and opposed to a counter substrate, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, in a switch matrix type liquid crystal panel, a pixel group is formed on a light valve substrate constituting the switch matrix type liquid crystal panel, and a switching element is provided for each pixel to select each pixel. This is performed by operation.
As this switch element, a thin film transistor formed on the surface of an amorphous silicon thin film or a polycrystalline silicon thin film deposited on a glass substrate, usually an insulated gate field effect transistor is used. The control of this switch element
It is controlled via an X driver and a Y driver installed around the pixel group.

A signal for driving the X driver and the Y driver is supplied from an external input / output terminal via a pad extracting portion provided on the panel. The pixel electrode is ITO
And the like. The pixel electrode group and the switch element are provided on the liquid crystal layer side and have a structure in contact with the liquid crystal layer via an alignment layer.

[0004]

As described above, in a conventional switch matrix type liquid crystal panel, a pixel electrode and a switch element formed on a substrate are provided on a liquid crystal side. However, since the switch element is thicker than the pixel electrode, the surface on which these are formed has significant irregularities. Therefore, in a conventional liquid crystal panel having an alignment layer on this surface, uneven alignment is unavoidable and causes display unevenness.

[0005] Such unevenness in alignment tends to promote the tendency to increase the degree of integration in the pixel portion, so that display unevenness cannot be ignored and restricts the degree of integration. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a semiconductor device for a light valve substrate having no display unevenness and a high degree of integration, and a suitable manufacturing method thereof.

[0006]

The main means adopted by the semiconductor device for a light valve substrate according to the present invention to achieve the above object is to form an insulating transparent thin film substrate and a matrix-shaped upper surface on the insulating transparent thin film substrate. And a single-crystal thin-film semiconductor layer fixed to a portion excluding the pixel electrode. A plurality of switch groups for supplying power, an X driver and a Y driver for controlling these switch groups are integrally formed, and an alignment layer is formed on the lower surface of the insulating transparent thin film substrate; A light-shielding film is formed on the lower surface of the thin-film substrate so as to face the position where the single-crystal thin-film semiconductor layer is located. Do Head extraction unit is provided,
On the upper surface of the insulating transparent thin film substrate, the pad take-out portion is connected to an X driver and a Y driver via a wiring pattern.

[0007] The main means adopted for manufacturing the device is that the light-shielding film and the pad extracting portion can be formed simultaneously.

[0008]

As described above, the alignment layer is provided on the surface opposite to the surface on which the pixel group including a plurality of pixel electrodes and switch elements is formed. On this surface, a light-shielding film is formed under the single-crystal thin-film semiconductor layer, and there is no other portion, and it is undeniable that there is some unevenness. It is so small as to be incomparable with the unevenness caused by the difference in height.

[0009] Therefore, this surface without the tall switch element is almost flat and the alignment operation can be easily performed, so that an even alignment film can be formed. In addition, the pad extracting portion 15 is exposed on this surface, and an efficient manufacturing method that can be formed simultaneously with the light shielding layer can be adopted.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an embodiment of the present invention. Reference numeral 1 denotes an insulating transparent thin film, on which a plurality of pixel electrodes 3 are arranged in a matrix. A semiconductor single crystal thin film layer is formed in a portion excluding the pixel electrode, and a switch element 4 is formed in a portion adjacent to each pixel electrode 3 there.

An X driver 21, a Y driver 22, and a pad take-out unit 15,
A wiring pattern 10 for connecting these is provided.
The switch element 4 is a field-effect transistor. The drain electrode is connected to the corresponding pixel electrode 3, the gate electrode is connected to the scanning line 19, and the source electrode is connected to the signal line 20. Further, the scanning line 19 is connected to the Y driver 22.
The signal line 20 is connected to an X driver 21, and each of the drivers is connected to an external circuit (not shown) via a pad extracting unit 15. The pad take-out portion 15 is described with reference to FIG. 2, but penetrates to the lower surface of the insulating transparent thin film, and the surface of the pad take-out portion 15 is exposed there.

Although a polarizing plate is further provided on the uppermost portion of the above-described thin film substrate, it is omitted here for convenience of explanation.
FIG. 2 shows an AA ′ cross section of FIG.
Wiring pattern 10, light shielding film, and pad extracting portion 15
Shows the relationship. As is apparent from FIG. 2, the pad extracting portion 15 penetrates from the upper surface to the lower surface of the insulating transparent thin film 1 and is exposed to the lower portion avoiding the pixel electrode portion. An external signal line (not shown) is connected to this,
Through this, a signal is transferred to each of the drivers 21 and 22.

The X driver 21 and the wiring pattern 10 are surrounded by an electrically insulating protective film 9, on which a transparent electrically insulating substrate 13 is fixed via an adhesive, and on which a polarizing plate 23 is mounted. . On the lower surface of the insulating transparent thin film 1, the surface of the above-described pad extracting portion 15 is exposed, and a light shielding film 14 is provided at a position facing the X driver 21.

FIG. 3 is a sectional view of an embodiment in which a light valve device is constructed using the single crystal thin film semiconductor device for a light valve substrate of FIG. An opposing substrate is provided on the lower surface of the insulating transparent thin film 1 in FIG. 1 at a position facing the pixel electrode group with an interval. The space is filled with liquid crystal 17, and the side surface is sealed with resin 25. The opposing substrate includes the alignment film 16, the transparent electrode 26, and the glass substrate 18.

The cutting portion of the light valve device is taken along the line BB 'in FIG.
It corresponds to the position of the line, but for convenience of explanation, the pixel electrode 3
Are displayed smaller than those of the switch element 4. A pixel electrode is formed by preparing a substrate in which a single-crystal thin-film semiconductor layer 2 is thermocompression-bonded on the entire surface of an insulating transparent thin film 1 and etching away a part of the single-crystal thin-film semiconductor layer 2 into a predetermined shape. The surface of the lower insulating transparent thin film 1 is exposed, and a plurality of electrodes 3 are formed thereon in a matrix. This means may be a commonly used means.

The switch element is a single crystal thin film semiconductor layer 2
Then, an insulated gate field effect transistor including a gate electrode 5, and a pair of impurity diffusion regions, that is, a source electrode 6 and a drain electrode 7, is formed. Drain electrode 7
Is connected to the corresponding pixel electrode 3, and the gate electrode 5 is arranged on the channel formation region of the switch element 4 via the insulating film 8.

On the upper side of the switch element 4, a wiring pattern 10 made of aluminum or the like is formed via an insulating film 9. This wiring pattern 10 is connected to the source electrode 6 of the switch element 4 through a contact hole formed in the insulating film 9.
, And further, as shown in FIG. A protective film 11 is formed on the surface of the wiring pattern 10, and a transparent electrically insulating substrate 13 is mounted thereon with an adhesive layer interposed therebetween to prevent damage due to mechanical stress. The point that the polarizing plate 23 is placed thereon is the same as that described in FIG.

Switch element 4 with insulating transparent thin film 1 interposed
In addition, a light shielding film 14 is provided below the Y driver 22 to prevent undesired operations due to light. An external signal is input from a pad extracting unit (not shown) to perform a well-known liquid crystal panel operation. That is, the gate electrode 5 of each switch element is connected to the scanning line 19 (see FIG. 1).
Therefore, the scanning line signal is applied by the Y driver 22 to control the conduction / interruption of the individual switch elements line by line.

The image signal output from the X driver 21 is applied to the image electrode 3 via the selected switch element 4 in the conductive state via the signal line 20. As a result,
Electric charges corresponding to the magnitude of the image signal are supplied to and stored in each image electrode 3. The accumulated charge causes the liquid crystal layer 17
Excites and changes its transmittance to perform a light valve function.
At the time of non-selection, the switch element 4 is non-conductive, and the image electrode 3 holds the previously written image signal as electric charge.

Since the switch element 4 is shielded from light by the light-shielding film 14, no light leakage current is generated when the switch element 4 is non-conductive, and the electric charge held in the pixel electrode 3 does not leak. Therefore, a stable light valve function is exhibited. Further, since the switch element 4 is formed on the silicon single crystal thin film 2 having extremely high charge mobility, a light valve device having high-speed signal response can be configured. Furthermore, since a circuit including the X driver 21 and the Y driver 22 can be formed on the same silicon thin film at the same time as the switch element 4, there is an effect that the manufacturing process is simplified.

FIG. 4 is an explanatory view schematically showing a process of manufacturing a single crystal thin film semiconductor device for a light valve substrate according to the present invention. First, a substrate shown in FIG. 4A is prepared. This is obtained by attaching a silicon single crystal thin film 2 on a silicon substrate 41 via a silicon dioxide layer 1 which is an insulating transparent thin film. The silicon substrate 41 is used to maintain mechanical strength when processing the surface of the single crystal thin film 2.

Next, the silicon single crystal thin film 2 corresponding to the position of the pixel electrode is removed by a known method. An X driver 21, a Y driver 22, a switch element 4 and the like are formed on the remaining single crystal thin film by a known method, and a transparent conductive layer is formed on a portion where the single crystal thin film is removed and the silicon dioxide layer 1 is exposed. To form the pixel electrode 3 (see FIG. 4B). Thus, a protective film, a wiring pattern, and the like (not shown) are formed on the formed pixel electrode 3 and the driving elements 21, 22, and 4 thereof. FIG. 4B shows the thus created one as a force diagram.

Further, as shown in FIG. 4C, an adhesive layer 12 typified by silicon dioxide or the like is applied thereon, and a glass substrate 13 with a polarizing plate is mounted thereon. Next, the silicon substrate 41 is placed upside down and the silicon substrate 41 is placed on the upper surface, and the silicon substrate 41 is completely removed by etching to expose the silicon dioxide layer 1. This is shown in FIG. 4D. In this state, FIG.
As shown in (1), through holes are formed at predetermined positions by etching to form through holes (a plurality of holes) of the pad extracting portion 15. Further, a metal such as aluminum is deposited on the entire surface of the through-hole so as to have a light-shielding thickness in a state where the through-hole is opened. This state is shown in FIG. 4F.

An undesired portion such as a portion corresponding to the pixel electrode is removed from the metal deposition surface 42 by a patterning process, and the pad extracting portion 15 and the light shielding film 14 are simultaneously formed. After that, an alignment layer is provided at a position corresponding to the pixel portion. FIG. 4G shows the completed drawing. FIG. 5 is a detailed view for explaining the connection relationship between the pad extracting portion 15 and the wiring pattern 10. The pad extracting portion 15 penetrates the silicon dioxide layer 1 from the lower surface to the upper surface and forms a driver 21 (22). It is connected to the wiring pattern 10.

[0025]

The present invention comprises a pixel electrode and a switch element having different thicknesses, and avoids a surface having a pixel portion in which unevenness is inevitable. Therefore, it is easy and reliable to form an alignment film, and thus there is an effect of eliminating alignment unevenness. Therefore, when the light valve device is configured, display unevenness is eliminated, and a light valve device with a higher degree of integration can be realized.

Further, since the pad take-out portion 15 is provided so as to be exposed on the side of the insulating transparent thin film on which the alignment film is formed, it is not necessary to provide a new space for the pad take-out portion 15.
In addition to downsizing, there is an advantage in manufacturing that the light shielding layer and the pad extracting portion 15 can be formed simultaneously. Further, since the switching element 4 is formed on the silicon single crystal thin film 2 having extremely high charge mobility, there is an effect that a light valve device having high-speed signal response can be configured.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line A-A 'of FIG.

FIG. 3 is a sectional view of a light valve device using the present invention.

FIG. 4 is an explanatory view of a manufacturing process of the present invention.

FIG. 5 is an explanatory view of a pad take-out part of the present invention.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Insulating transparent thin film 2 Single crystal thin film semiconductor layer 3 Pixel electrode 4 Switch element 5 Gate electrode 6 Source electrode 7 Drain electrode 8 Gate insulating film 9 Electrically insulating protective film 10 Wiring pattern 11 Protective film 12 Adhesive layer 13 Transparent electrical insulation Functional substrate 14 Light-shielding film 15 Pad take-out part 16 Alignment film 17 Liquid crystal layer 18 Glass substrate 19 Scanning line 20 Signal line 21 X driver 22 Y driver 23 Polarizing plate 24 Transparent conductive thin film 25 Sealing resin 26 Transparent electrode

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-101832 (JP, A) JP-A-1-267616 (JP, A) JP-A-61-156025 (JP, A) JP-A-63-163 104026 (JP, A) JP-A-63-178562 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/136 G02F 1/1335

Claims (4)

(57) [Claims] An insulative transparent thin-film substrate, a pixel electrode group comprising a plurality of pixel electrodes arranged in a matrix on an upper surface of the insulative transparent thin-film substrate, and a single electrode fixed to a portion excluding the pixel electrodes. A plurality of switches for selectively supplying power to the pixel electrodes, and an X for controlling these switches.
A semiconductor device for a light valve substrate, wherein a driver and a Y driver are integrated and an orientation layer is formed on a lower surface of the insulating transparent thin film substrate. 2. A light valve substrate semiconductor device, wherein a light shielding film is formed on a lower surface of the insulating transparent thin film substrate so as to face a position where the single crystal thin film semiconductor layer is located. 3. An insulative transparent thin-film substrate is provided with a pad extracting portion penetrating therethrough and exposed from an upper surface to a lower surface. A semiconductor device for a light valve substrate, wherein the semiconductor device is connected to a driver and a Y driver via a wiring pattern. 4. A step of preparing a substrate comprising three layers of a semiconductor substrate, an insulating transparent thin film substrate, and a single crystal thin film semiconductor layer, and removing the single crystal thin film semiconductor layer corresponding to a pixel portion from the substrate. A pixel electrode is formed thereon, and an X driver, a Y driver, and a switch element are integratedly formed on the remaining single crystal thin film semiconductor layer to form a pixel electrode and a driving circuit thereof. Placing a glass with a polarizing plate on the pixel electrode and its driving circuit via an adhesive layer, removing the semiconductor substrate, exposing the lower surface of the insulating transparent thin film substrate, Forming a through hole at a predetermined position on the exposed insulating transparent thin film substrate, and subsequently depositing a metal film over the entire lower surface of the insulating transparent thin film substrate; and patterning the deposited metal film. Forming a light-shielding layer at a position facing the remaining single-crystal thin-film semiconductor layer, and simultaneously forming a pad extraction portion at the through-hole portion; and following the above-described process, a switch element and a pixel electrode Forming an alignment film at opposing positions. A method for manufacturing a semiconductor device for a light valve substrate.