JPH09172180A - Semiconductor device and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constantly maintain the strength of a light-transmissive film even when the thickness of the film is thin and the gap between the light-transmissive film and a liquid crystal layer even when the liquid crystal layer is stood by forming part of the light-transmissive film of a porous single-crystal semiconductor layer and a porous oxide layer obtained by oxidizing the semiconductor layer. SOLUTION: A light-transmissive area 2 is simultaneously formed when an element separating area is formed for forming a semiconductor element in an opaque area 1. To be concrete, a thick porous oxide film 10 is grown by oxidizing a porous single-crystal semiconductor layer simultaneously with the selective oxidation of an opaque semiconductor layer. While the film 10 is formed thick, the volume of the film 10 and the level difference between the film 10 and a single-crystal semiconductor substrate 100 do not increase much, because the film 10 is formed from a porous layer obtained by etching the substrate 100. Therefore, a semiconductor element which has to be formed on the opaque substrate and another semiconductor element requiring a high performance can be formed integrally on the same substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device provided with a semiconductor element, and particularly to a non-single crystal semiconductor element and a single crystal by removing a single crystal semiconductor substrate directly under a light transmissive film from another main surface side. The present invention relates to a semiconductor device and a liquid crystal display device in which a semiconductor element is provided on the same base.

[0002]

2. Description of the Related Art First, a conventional semiconductor device used in a liquid crystal display device will be described. Conventionally, a liquid crystal display device provided with an active matrix element has been commercialized as a flat panel display or a projection television.

FIG. 10 shows a schematic configuration diagram of a drive circuit of an active matrix type liquid crystal display element which has been conventionally used. In the figure, 301 is a pixel switch, 305 is a liquid crystal pixel, 306 is a transparent substrate, 302 is a buffer section, 30
Reference numeral 3 is a horizontal shift register unit, and 304 is a vertical shift register unit. Here, the luminance signal in the video signal of the television is compressed into a certain band and sent to the driving buffer unit 302. Next, the brightness signal is transferred from the buffer unit 302 to the liquid crystal pixels 305 according to the timing of the horizontal shift register unit 303 while the pixel switch 301 is ON by the vertical shift register unit 304. Liquid crystal pixel 3
In 05, the amount of transmitted light changes according to the luminance signal, the transmittance changes for each pixel, and color liquid crystal display is performed through the separately provided color filters.

Here, regarding the performance required for each circuit such as the buffer section 302 and the pixel switch 301, in consideration of a high-definition television, the frame frequency is 60 Hz, the number of scanning lines is about 1000, and the horizontal scanning period is about 30 μsec (effective). If the number of horizontal pixels is about 1500, the scanning period is 27 μsec.
The TV signal has a frequency of about 45 MHz and the buffer unit 302
Will be transferred to. Therefore, as the performance required for each element circuit, the driving capacity of the horizontal shift register unit 303 is 45 MHz.
As described above, the driving capacity of the vertical shift register 304 is 500 kHz.
z or more, the transfer switch driven by the horizontal shift register unit 303 and transferring the television signal to the buffer unit 302 has a drive capability of 45 MHz or more, and the pixel switch 301 has a drive capability of 500 kHz or more. The driving capability here means that, when the number of gradations N in the liquid crystal pixel 305 is to be obtained, the voltage that gives the maximum or minimum transmittance of the liquid crystal can be obtained from the Vm, VT (voltage-transmittance) curve. When the threshold voltage of the liquid crystal is Vt, it means that a voltage of Vm- (Vm-Vt) / N [V] (1) or more is transferred during the above period.

As is apparent from this, the pixel switch 3
01 and the vertical shift register unit 304 may have relatively small driving capability, but the horizontal shift register unit 30
3 and the buffer unit 302 are required to be driven at high speed. Therefore, in the current liquid crystal display element, the pixel switch 301 and the vertical shift register unit 304 are formed of a polycrystalline silicon TFT or an amorphous silicon TFT deposited on a glass substrate in a monolithic manner with the liquid crystal, and other peripheral circuits are This is achieved by mounting the IC chip from the outside. Attempts have been made to form a peripheral circuit in a monolithic manner by using a polycrystalline silicon TFT, but since the driving capability of each TFT is small, it is necessary to increase the transistor size or to make a complicated design in the circuit. On the other hand, for a viewfinder for a VTR camera or a projection type display using a liquid crystal image display device, it is important that the substrate is light transmissive in the visible light region.

As described above, in order to realize a high-performance liquid crystal image display device, each circuit capable of high-speed driving and a high-performance peripheral driving circuit for liquid crystal pixels are required. As the semiconductor layer in which is formed, it is desirable to use a single crystal semiconductor layer having excellent crystallinity. Also,
The peripheral drive circuit needs to be shielded from light.

On the other hand, the active matrix element for orienting the liquid crystal according to the signal does not necessarily have to be formed of a single crystal transistor, but it is necessary to form the transistor on the light transmitting film.

[0008]

As described above, conventionally, the formation of the light-transmitting film forming these transistors uses a semiconductor oxide film formed by oxidation of a single crystal semiconductor substrate, or chemical vapor deposition (CVD). ) Method and physical vapor deposition (PV
An oxide film formed by the method D) was used. For this reason, it is necessary to diffuse oxygen in the semiconductor oxide film in order to proceed with oxidation, and the film thickness of the light transmissive film can be formed only to a film thickness of several μm due to the demand for oxygen diffusion.

Further, in the deposited film, when the film thickness is increased, cracks and the like occur in the film due to film stress, and the film thickness is also limited to several μm. In the semiconductor device and the liquid crystal display device thus formed, the transparent film in the removed portion of the single crystal semiconductor substrate has a small film thickness, the strength is not sufficient, and the reliability is not sufficiently satisfied.

Further, when the liquid crystal display device is constructed, liquid crystal is sealed between the transparent substrate facing the light transmissive film. These liquid crystal display devices are usually used with the display surface upright.
A liquid crystal display device arranged in this way is shown in FIG. In the figure, a light transmissive region 1 and a light transmissive region 2 are provided on a substrate 100, a semiconductor element 3 including a single crystal semiconductor layer as an active region is provided on the light transmissive region 1, and a light transmissive region is provided. A semiconductor element 4 including a non-single crystal semiconductor layer as an active region is provided on the active region 2. Further, in order to obtain a liquid crystal display device, an alignment film 8 is provided on the translucent region 2, a cover glass 7 having a transparent electrode and the alignment film 8 is arranged thereon as a counter substrate, and the nematic liquid crystal 5 is filled therein. Then, the periphery is sealed by the sealing member 6.

Since the liquid crystal layer 5 is held upright, the pressure of the liquid crystal at the bottom of the display surface increases due to the influence of gravity, and the light transmissive film 9 is deformed, resulting in a gap at the bottom of the liquid crystal layer 5. D2 increases and conversely the upper gap D1 decreases. By changing the thickness of the liquid crystal layer in the display surface in this way, the transmittance of the liquid crystal layer and the display color change.
The structure was inappropriate as a display device.

An object of the present invention is to form a light transmissive film capable of increasing the thickness of a semiconductor oxide film, maintain the strength even if the film thickness of the transmissive film in the removed portion of the single crystal semiconductor substrate is small, and to improve the liquid crystal layer. It is an object of the present invention to provide a semiconductor device that can keep the gap constant even in an upright state and a liquid crystal display device using the semiconductor device.

[0013]

According to the present invention, there is provided a semiconductor device comprising:
A semiconductor device using a substrate manufactured by removing a single crystal semiconductor region directly below a translucent film of a light transmissive film formed on one main surface side of a single crystal semiconductor substrate from the other main surface, At least a part of the transparent film is composed of a single crystal semiconductor porous layer formed by etching a part of the single crystal semiconductor substrate and a porous oxide layer formed by oxidizing the single crystal semiconductor porous layer.

Further, a non-single-crystal semiconductor element is formed on the translucent film, a single-crystal semiconductor element is formed in the remaining single-crystal semiconductor region of the substrate, and the non-single-crystal semiconductor element and the single-crystal semiconductor element are formed. A crystal semiconductor element is electrically connected.

Further, the liquid crystal display device of the present invention is a substrate manufactured by removing the single crystal semiconductor region directly below the translucent film formed on one principal surface side of the single crystal semiconductor substrate from the other principal surface. In the semiconductor device to be used, at least a part of the transparent film is a single crystal semiconductor porous layer formed by etching at least a part of the single crystal semiconductor substrate and a porous oxide formed by oxidizing the single crystal semiconductor porous layer. It consists of layers.

Further, an active matrix element is formed on the translucent film, a drive circuit element is formed in the remaining single crystal semiconductor region of the substrate, and the active matrix element and the drive circuit element are electrically connected. Are connected to each other.

Further, the present liquid crystal display device is characterized in that a silicon single crystal substrate having a (100) plane as a main surface is used as a single crystal semiconductor substrate. By making the main surface the (100) plane, the side wall of the etched portion can be formed by the (111) plane.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION First, the principle of the present invention and the principle forming process will be described. The present invention is manufactured by removing the single crystal semiconductor region directly below the translucent film formed on one main surface side of the single crystal semiconductor substrate from the other main surface. At least a part of the light-transmitting light-transmitting film is formed by etching a part of the single crystal semiconductor substrate to form a single crystal semiconductor porous layer and further oxidizing the single crystal semiconductor porous layer. It is composed of a porous oxide layer having translucency. The thickness of the single crystal semiconductor porous layer can be easily controlled by the etching time, and a thickness of several tens of μm can be realized.

In addition, the density of the single crystal semiconductor porous layer can be controlled by etching conditions against the formation of an oxide film due to the oxidation of the semiconductor layer and the increase of the internal stress due to the increase of the film thickness which is a problem in the deposition of the oxide film. Therefore, a porous oxide layer formed by oxidizing the single crystal semiconductor porous layer is not a problem. Further, even if a step is formed due to an increase in volume due to the formation of an oxide film due to the oxidation of the semiconductor layer, the porous oxide layer etches the single crystal semiconductor substrate to oxidize the porous single crystal semiconductor porous layer.
The surface of the porous oxide layer is formed in substantially the same plane as the surface of the single crystal semiconductor substrate, and no step or the like is formed on the surface, which is suitable for subsequent element formation and wiring formation between elements.

By oxidizing the single crystal semiconductor porous layer whose density is controlled as described above, it is possible to easily form a thick porous oxide layer.

Further, a semiconductor element (for example, a thin film transistor) which does not require the performance of a single crystal is provided on the light-transmitting film of the substrate, and a single crystal semiconductor element is provided in the single crystal semiconductor region of the substrate. A semiconductor element that needs to be formed on an optical substrate (which does not require performance equivalent to a single crystal) and a semiconductor element that requires high performance can be integrally formed on the same substrate. is there.

According to the present invention, the semiconductor element that needs to be formed on the translucent substrate as described above and the semiconductor element that requires high performance can be integrally formed on the same substrate. It is not necessary to fabricate the semiconductor elements on different substrates and connect them by mechanical connection such as wire bonding, and electrical connection is possible (connection can be made by Al wiring by ordinary vapor deposition technology).

Further, according to the present invention, a circuit portion requiring high performance can be provided on a single crystal semiconductor substrate and can be constituted by a single crystal semiconductor element. Therefore, the element size generated when such a circuit portion is constituted by a non-single crystal semiconductor is provided. And the complicated design of the circuit (block division drive as an example) does not occur, and the manufacturing process is simplified.

The present invention is preferably used in an active matrix type liquid crystal display device. That is, an active matrix type liquid crystal display device is required to be provided with an active matrix element such as a thin film diode or a thin film transistor on a translucent substrate and a drive circuit such as a shift register to be a single crystal semiconductor element. If used, the active matrix element and the drive circuit can be integrally formed on the same substrate and can be electrically connected without being connected by mechanical connection such as wire bonding.

Further, since the light-transmissive film can be formed thicker, the strength and the reliability can be sufficiently satisfied. Further, since the translucent film can be formed sufficiently thick, it is possible to prevent the thickness of the liquid crystal layer from changing when used as a liquid crystal display device.

[First Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The semiconductor device of the present invention is preferably used for a liquid crystal display device having a liquid crystal element as an optical element, an optical sensor device having a photoelectric conversion element as an optical element, and the like. In particular, it is characterized by a substrate forming a semiconductor element preferably used for an optical element or the like which requires translucency.

First, in order to facilitate understanding of the present invention,
A semiconductor device according to the present invention will be described with reference to FIG. FIG. 1 is a schematic sectional view showing a liquid crystal display device as an example of the semiconductor device of the present invention. In the figure, 10
Reference numeral 0 is a single crystal semiconductor substrate, 1 is a non-translucent region in the peripheral portion of the single crystal semiconductor substrate 100, 2 is its translucent region, 3 is a semiconductor element formed in the region of the single crystal semiconductor substrate 100, 4
Is a semiconductor element formed in the non-single crystal semiconductor layer region, 5 is a liquid crystal material, 6 is a sealing member, 7 is a cover glass, 8 is an alignment film for promoting the alignment of the liquid crystal material 5, and 9 is NSG (Non-doped Silica).
The transparent film 10 of te glass) is a single crystal semiconductor porous layer.

In FIG. 1, the single crystal semiconductor substrate 100 is provided with a non-translucent region 1 and a translucent region 2.
At least one semiconductor element 3 including a single crystal semiconductor layer as an active region is provided in the non-translucent region 1, while a non-single crystal semiconductor layer as an active region is provided on the translucent region 2. At least one including semiconductor element 4 is provided. Further, in order to form a liquid crystal display device, the transparent region 2
A cover glass 7 having an alignment film 8 provided thereon and a void provided thereon and having a transparent electrode and an alignment film (not shown) as a counter substrate.
Are arranged, the nematic liquid crystal 5 is filled therein, and the surroundings are sealed by a sealing member 6. Further, a liquid crystal display device is formed by sandwiching it between polarizing plates (not shown) on the outside of the cover glass 7.
Here, as the semiconductor elements 3 and 4 used in the present invention, a three-terminal element such as a bipolar transistor or a MOS transistor, or a two-terminal element such as a diode is preferably used. In the case of a color liquid crystal display device, a color filter is formed inside the cover glass 7 together with a black matrix.

A single crystal semiconductor is preferably used as the non-translucent region 1, and the non-translucent region 1 can be easily made non-transparent by adjusting the thickness or providing a light shielding layer.

On the other hand, as the translucent region 2, a thick film which is insulating and less deformed than a thin film is preferably used. Specifically, it is a porous oxide layer 10 of silicon oxide and a single layer or multiple layers of silicon oxide or silicon nitride deposited thereon, for example, NSG 9. The non-single-crystal semiconductor used for the semiconductor element 4 provided thereon has a crystal structure such as polycrystal (polysilicon), microcrystal (microsilicon), and amorphous (amorphous). Can be easily formed as a thin film by a chemical vapor deposition method (CVD method) or a physical vapor deposition method (PVD method).

The semiconductor element 4 is preferably used as a pixel switch, while the semiconductor element 3 is used to form a peripheral circuit such as a drive circuit for driving the semiconductor element 4.

On the other hand, when a photoelectric conversion element is used as the optical element, the non-single crystal semiconductor layer 8 may be used as the photoelectric conversion portion or the active area of the switching transistor on the light-transmissive area 2.

As the single crystal semiconductor substrate 100 of the present invention, a transparent insulating film is formed on a substrate made of a single crystal semiconductor, and then the substrate at a portion to be transparent is selectively removed. The substrate obtained is preferably used.

More preferably, the translucent region 2 is formed at the same time when the element isolation region for forming the semiconductor element is formed in the non-translucent region 1. Specifically, the single crystal semiconductor porous layer is oxidized at the same time as the selective oxidization of the non-translucent semiconductor layer to grow a thick transparent porous oxide film 10. The porous oxide film formed as a light-transmitting film is formed thick, but since the single crystal semiconductor substrate is formed from an etched porous layer, the increase in volume is moderated and the step difference with the single crystal semiconductor substrate is reduced. It Therefore, since the levels of the surfaces on the non-translucent region 1 and the translucent region 2 are almost the same and are flattened, the wiring between the elements in each of the non-translucent region 1 and the translucent region 2 is formed. Can be easily done by the conventional method.

[Second Embodiment] Next, the manufacturing process of the liquid crystal display device will be described with reference to FIGS.
In FIG. 2, first, a silicon wafer 201 having a (100) plane on its main surface is prepared. Silicon wafer 2
As 01, a single crystal silicon layer to which impurities are added so as to have an N-type conductivity is used. As shown in FIG. 2, the silicon wafer 201 is covered with a mask material of a resist 220 such as Apiezon Wax (registered trademark) except the portion where the transparent region 200 is formed.

After that, using a mixed solution of hydrofluoric acid and ethanol as an etching solution, the translucent region 2 to be the opening of the mask.
00 is brought into contact with the etching solution. An electrode is formed on the back surface side of the silicon wafer 201, and a platinum electrode is placed in the etching solution. While irradiating the etching surface with light, a voltage is applied between the back electrode of the silicon wafer 201 and the platinum electrode to electrolytically etch the silicon in the opening of the mask forming the transparent region 200. Electrolytic etching occurs only in the opening and is locally transformed into a porous silicon layer by the progress of etching, and a single crystal silicon porous layer 200 is formed on the silicon wafer 201.

On the other hand, the region where the single crystal silicon porous layer 200 is formed is the above-mentioned Apiezon wax (registered trademark).
In addition to the mask described above, there is a method of using a resist having resistance to hydrofluoric acid, and a method of preventing the etching solution from coming into contact with the surface of the silicon 201 by an O-ring or the like. Furthermore, a method may be used in which doping atoms are injected only into the etching region by an ion injection method or the like to reduce the resistance as compared with other portions of the silicon wafer 201. Further, although the N-type silicon wafer is used in the above, the P-type silicon wafer may be used to advance the etching without the need of irradiating light at the time of etching.

In this way, the silicon wafer 201 in which the single crystal silicon porous layer 200 is formed on a part of the single crystal silicon substrate is formed. This silicon wafer 201
3, peripheral drive circuits 205 and 206 are formed in a CMOS structure by a known single crystal wafer semiconductor process in the single crystal silicon region of FIG. The single crystal silicon porous layer 200 of the silicon wafer 201 is oxidized at the same time as the single crystal silicon by the field oxidation process performed first when forming the peripheral drive circuit. Here, in the single-crystal silicon porous layer 200, SiO2 is laminated in the porous silicon layer, the oxidation rate advances rapidly, and almost the entire layer is oxidized without any change in the overall deposition. In this embodiment, the thickness of the field oxide film 202 formed in the non-translucent region 220 is set to 1 μm. The thickness of the porous silicon oxide layer 215 is almost the same as that of the single crystal silicon porous layer.

A method for forming a transistor formed in a single crystal silicon region is shown below. n-MOS transistor 2
06, p-MOS transistor 205 uses polycrystalline silicon as the gate material, and the thickness is set to 400 nm. The source and drain are formed in a self-aligned manner by an ion implantation method, and the n-MOS transistor 20
6, 1 × 1 for each p-MOS transistor 205
Implant As ¹⁶ / cm ² and BF ₂ 2 × 10 ¹⁵ / cm ² .

After implanting impurity ions into the source / drain portions, NSG (Non-doped Silicate) of about 200 nm is formed.
Glass) 203 is deposited by the atmospheric pressure CVD method. Next, the polycrystalline silicon 204 is formed to a thickness of 250 nm by the low pressure CVD method.
Deposit to a degree. Then, boron (As) is added at 1 × 10 ¹¹ /
Implant the whole surface of cm ² by the ion implantation method (the above is shown in FIG. 3).

Next, as shown in FIG. 4, a resist pattern is left in the form of islands in the active matrix element forming portion by photolithography, and the resist is used as a mask by isotropic dry etching to form the NSG layer 20.
A polycrystalline silicon region 204 on 3 is formed in a predetermined shape. After this, by pyrogenic oxidation at 950 ° C,
A 50 nm oxide film 207 is grown in the polycrystalline silicon region 204. This becomes the gate oxide film of the thin film transistor.

Next, as shown in FIG. 5, polycrystalline silicon for the third time is deposited on the oxide film 207 by a low pressure CVD method,
The gate electrode 208 of the thin film transistor is formed by anisotropic etching. After this, the peripheral drive circuit portion 20
Masking 5,206 etc. with resist and arsenic 5 ×
About 10 ¹⁵ / cm ^{2 is} implanted by the ion implantation method. Further, heat treatment is performed at 900 ° C. for 20 minutes in a nitrogen atmosphere to form a thin film transistor.

Next, as shown in FIG. 6, the NSG layer 209 is formed.
Is deposited over the entire surface including the peripheral drive circuit by about 500 nm by the atmospheric pressure CVD method, and contact holes are formed in the source and drain regions and the gate electrode region of the transistor.

At this time, the thickness of the interlayer insulating film (203 + 209) in the peripheral drive circuit region (region I) is 700 nm and the thickness of the interlayer insulating film 2 in the active matrix element region (region II) is 2.
Since the thickness of 09 is different from 500 nm, even if contact holes are separately formed in the regions I and II, CHF ₃ -C ₂
There was no problem in F ₆ type dry etching.

After that, an electrode material such as aluminum is deposited by the sputtering method and processed into a predetermined wiring shape by the dry etching method to form the wiring 210. In this step, the non-single crystal semiconductor element in the region II and the single crystal semiconductor element in the region I can be electrically connected.

Next, as shown in FIG. 7, a pixel portion is formed of a transparent electrode material such as ITO (Indium Tin Oxide), which is a known technique, and the entire surface is covered with a transparent insulating film 211.
After that, the sealing material 212 and the glass cover 214 are attached, and the liquid crystal 213 is sealed between the transparent insulating film 211 and the glass cover 214.

Finally, as shown in FIG. 8, silicon is cut out from the back surface of the silicon wafer 201 with potassium hydroxide (KOH) or an organic alkali such as ethylenediamine. Since the main surface of the silicon wafer 201 is the (100) plane, the etching surface proceeds uniformly from the main surface. The axial direction of the etching region needs to be aligned with <110> or the like. The wet etching solution does not dissolve silicon dioxide and etching stops at the porous silicon oxide layer 215. As a result,
The active matrix element region becomes transparent and functions as a liquid crystal image display device.

Although one embodiment of the present invention has been described in detail above, the following modifications are possible.

That is, although the above-mentioned active matrix element uses the n-channel type MOSFET, it may use the p-channel type MOSFET.

Although the peripheral driving circuit is composed of a CMOS circuit, it may be composed of a Bi-CMOS circuit including a bipolar transistor in consideration of improvement of driving ability.

Further, the following manufacturing method is also possible to reduce the steps.

The NSG film 203 shown in FIG. 3 is omitted, and the n-MOS transistor 206 and the p-MOS are previously formed.
The gate electrode portion of the transistor 205 is thermally oxidized to about 30 nm. At this time, the n-MOS transistor 20
6, both p-MOS transistor 205 source
Do not implant impurities in the drain region. After forming the gate electrode of the thin film transistor, the peripheral driving circuit portion and the source / drain regions of the thin film transistor are formed simultaneously. The subsequent steps are the same as the manufacturing steps described above.

Whether or not the process shortened in this way is determined by the second
At the time of dry etching of the polycrystalline silicon layer 204, it depends on whether or not the selection with respect to silicon dioxide can be made high, but the present dry etching apparatus using CF ₄ is sufficiently possible.

[Third Embodiment] The third embodiment of the liquid crystal display device of the present invention will be described in detail. In this embodiment mode, the influence of the thickness of the porous silicon oxide layer forming the light-transmitting region will be described. Similar to the first and second embodiments, electrolytic etching is performed by masking the silicon wafer 201 except for the portion where the transparent region 200 is formed with a resist. In this case, the state of the single crystal silicon porous layer 215 formed depends on the etching time and the current value. In this embodiment mode, the thickness of the single crystal silicon porous layer 215 is changed depending on the etching time. In the following steps, the liquid crystal display device is formed through the same steps as the example described in the second embodiment.

The liquid crystal display device formed in this step is shown in FIG.
Leaned against it as shown in. The thickness of the oxidized porous silicon oxide layer and the thickness D1 of the liquid crystal layer of the liquid crystal display device.
The change in the difference in D2 is shown in FIG. As can be seen from FIG. 9, the difference (D2-D1) in the thickness of the liquid crystal layer is reduced due to the increase in the thickness of the porous silicon oxide layer. When the thickness of the porous silicon oxide layer is 10 μm, the difference (D2−D1) in the thickness of the liquid crystal layer is about 0.01 μm, and the unevenness in the transmittance of the liquid crystal display device or the uneven color occurs due to the unevenness in the thickness of the liquid crystal layer. To do. Although these irregularities are reduced by increasing the thickness of the porous silicon oxide layer, it is preferable to form them to a thickness of about 15 μm or more in consideration of shortening the process.

[0057]

As described above, according to the present invention,
A single crystal semiconductor substrate is formed by removing a single crystal semiconductor region directly below a light-transmitting film formed on one main surface side of the single crystal semiconductor substrate from the other main surface. A substrate consisting of a part of the substrate and the other part composed of the single crystal semiconductor region, and a semiconductor element that does not require the performance of a single crystal is provided in the translucent film of the substrate. By providing a single crystal semiconductor element, a semiconductor element that needs to be formed on a translucent substrate (which does not require performance equivalent to a single crystal) and a semiconductor element that requires high performance are integrated on the same substrate. It becomes possible to form it.

In the present invention, the semiconductor element that needs to be formed on the translucent substrate and the semiconductor element that requires high performance can be integrally formed on the same substrate.
It is possible to electrically connect the semiconductor elements to each other without forming them on different substrates and connecting them by mechanical connection such as wire bonding.

Further, according to the present invention, since the circuit portion which is required to have high performance can be provided on the single crystal semiconductor substrate and constituted by the single crystal semiconductor element, the element size generated when such circuit portion is constituted by the non-single crystal semiconductor is reduced. There is no problem that increase and complicated circuit design (block division drive as an example) are required.

As a result, it is possible to provide an advantageous semiconductor device as the mounting cost is significantly reduced and the density of pixels is higher.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a liquid crystal display device of the present invention.

FIG. 2 is a cross-sectional view showing a manufacturing process of an embodiment of the liquid crystal display device of the present invention.

FIG. 3 is a cross-sectional view showing a manufacturing process of an embodiment of the liquid crystal display device of the present invention.

FIG. 4 is a cross-sectional view showing a manufacturing process of an embodiment of the liquid crystal display device of the present invention.

FIG. 5 is a cross-sectional view showing a manufacturing process of an embodiment of the liquid crystal display device of the present invention.

FIG. 6 is a cross-sectional view showing a manufacturing process of an embodiment of the liquid crystal display device of the present invention.

FIG. 7 is a cross-sectional view showing a manufacturing process of an embodiment of the liquid crystal display device of the present invention.

FIG. 8 is a cross-sectional view showing a manufacturing process of an embodiment of the liquid crystal display device of the present invention.

FIG. 9 is a graph showing the relationship between the thickness of a porous oxide layer and the thickness of a liquid crystal layer of a liquid crystal display device of Example 2.

FIG. 10 is a schematic configuration diagram of a drive circuit of an active matrix type liquid crystal display element which will be used in the future.

FIG. 11 is a cross-sectional view of a conventional liquid crystal display device in a standing state.

[Explanation of symbols]

 1,201 single crystal semiconductor substrate 2,202 translucent film 3,205,206 silicon single crystal transistor 4 thin film transistor 5,213 liquid crystal layer 6,212 sealing material 7,214 cover glass 203 NSG film 204 polycrystalline silicon region 207 Gate oxide film 208 Gate electrode of thin film transistor 209 NSG film 210 Metal wiring 211 Transparent insulating film 215 Porous silicon oxide layer 220 Resist 301 Pixel switch 302 Buffer part 303 Horizontal shift register part 304 Vertical shift register part 305 Liquid crystal pixel 306 Transparent substrate

Claims (12)

[Claims] 1. A semiconductor device using a substrate manufactured by removing a single crystal semiconductor region directly below a translucent film formed on one main surface side of a single crystal semiconductor substrate from the other main surface, wherein: At least part of the light-sensitive film is composed of a single crystal semiconductor porous layer formed by etching a part of the single crystal semiconductor substrate and a porous oxide layer formed by oxidizing the single crystal semiconductor porous layer. Semiconductor device. 2. The semiconductor device according to claim 1, wherein
A non-single crystal semiconductor element is formed on the transparent film, a single crystal semiconductor element is formed in the remaining single crystal semiconductor region of the base, and the non-single crystal semiconductor element and the single crystal semiconductor element are formed. Is electrically connected to the semiconductor device. 3. The semiconductor device according to claim 2, wherein
A semiconductor device, wherein the other part of the translucent film is formed by a chemical vapor deposition (CVD) method. 4. The semiconductor device according to claim 2, wherein
The semiconductor device, wherein the transparent film has a film thickness of 15 μm or more. 5. The semiconductor device according to claim 2, wherein
A semiconductor device, wherein the non-single crystal semiconductor element is a semiconductor element formed of polycrystalline silicon or amorphous silicon. 6. The semiconductor device according to claim 2,
A semiconductor device, wherein a silicon single crystal substrate having a (100) plane as a main surface is used as the single crystal semiconductor substrate. 7. A liquid crystal material on a semiconductor device using a substrate manufactured by removing a single crystal semiconductor region directly below a translucent film formed on one main surface side of a single crystal semiconductor substrate from the other main surface. In the liquid crystal display device including at least a part of the transparent film is formed by oxidizing a single crystal semiconductor porous layer formed by etching a part of the single crystal semiconductor substrate and the single crystal semiconductor porous layer. A liquid crystal display device comprising a porous oxide layer. 8. The liquid crystal display device according to claim 7, wherein an active matrix element is formed on the translucent film, and a drive circuit element is formed in the remaining single crystal semiconductor region of the base. A liquid crystal display device, wherein the active matrix element and the drive circuit element are electrically connected. 9. The liquid crystal display device according to claim 7, wherein the other part of the translucent film is chemical vapor deposition (CVD).
A liquid crystal display device formed by a method. 10. The liquid crystal display device according to claim 7, wherein the translucent film has a film thickness of 15 μm or more. 11. The liquid crystal display device according to claim 7, wherein the active matrix element is a thin film diode or a thin film transistor formed of polycrystalline silicon or amorphous silicon. 12. The liquid crystal display device according to claim 7, wherein a silicon single crystal substrate having a (100) plane as a main surface is used for the single crystal semiconductor substrate.