JP3278296B2 - Method for manufacturing liquid crystal display array - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display array used for a liquid crystal display or a light valve of a projection type projector.

[0002]

2. Description of the Related Art Previously, amorphous Si (hereinafter a-Si) or polycrystalline Si (hereinafter abbreviated as Pol) was used for a liquid crystal display or a light valve of a projection type projector for each pixel.
An active matrix type liquid crystal display array in which a thin film transistor (hereinafter referred to as a TFT) made of y-Si) is provided and a voltage is applied to a pixel electrode to drive a liquid crystal by this switching operation is often used because high image quality can be obtained. (Hereinafter, the liquid crystal display array refers to a transmissive liquid crystal display array). An a-Si TFT capable of forming a transistor on a large-area glass substrate is mainly used for a direct-view liquid crystal display, and a Poly-capable element capable of forming a small and high-performance transistor on a small-area quartz substrate is used for a light valve of a projection type projector. -Si TFT
Was used. However, in forming these TFTs,
Since a transparent or insulating glass or quartz substrate is used, there has been a problem that ordinary semiconductor manufacturing equipment and process conditions for a single crystal Si substrate cannot be used as they are.

[0003] In addition, as the definition of the screen has been advanced as represented by the HDTV, a dedicated IC is often mounted around the screen as a peripheral circuit at present, but when the pixel pitch is small, the mounting becomes difficult. It has been desired that peripheral circuits can be formed on the same substrate.

FIGS. 12A and 12B show, for example, the document IE
DM89-7.3 P165 to P168 and JP-A-2-1
FIG. 1 is a cross-sectional view and a plan view illustrating one pixel of a conventional liquid crystal display array disclosed in Japanese Patent No. 54232. In FIG. 12A, reference numerals 101, 104, and 105 denote channels, sources, and drains made of Poly-Si formed on an isolation insulating film 102 made of SiO _2.
A gate insulating film made of Si ₃ N ₄ , SiO ₂ or the like formed on the gate electrode, a gate electrode 3 made of Al, Ta, Cr, Si, etc., and a source 9, 10 made of Al, Ta, Cr, Si, etc. , A drain electrode. Reference numeral 6 denotes a storage capacitor electrode made of ITO formed on the isolation insulating film 102, and reference numeral 7 denotes Si ₃ N ₄ , SiO 2 formed on the storage capacitor electrode 6.
_A storage capacitor film made of ₂ or the like, 8 is a transparent pixel electrode made of ITO formed on the protection capacitor film 7, and 11 is a protection film made of Si ₃ N ₄ , SiO ₂ or the like for protecting the entire element surface. It is. Reference numeral 15 denotes a transparent support substrate made of glass, quartz, or the like, which is bonded to the isolation insulating film 102 by a bonding layer 14 made of an organic adhesive or the like.

[0005] In FIG. 12B, AA 'corresponds to FIG.
The cross-sectional line of FIG. Since the storage capacitor electrode 6 is formed of transparent ITO, it does not affect the aperture ratio, and the size is almost the same as the size of the transparent pixel electrode 8.
When the storage capacitor electrode 6 is made of an opaque metal such as Al, Ta, or Cr, it is necessary to minimize the size to suppress a decrease in the aperture ratio.

Next, a manufacturing method will be described. FIG.
(A)-(f) is sectional drawing which shows the manufacturing method of the conventional liquid crystal display array. FIG. 13A shows a step of forming an isolation insulating layer 102 made of a thermal oxide film on a single-crystal Si substrate 1 and further forming a Poly-Si channel 101 to be a TFT.

FIG. 13B shows a process of forming a Poly-Si TFT and a transparent pixel electrode 8, a storage capacitor electrode 6, a storage capacitor film 7, and a protective film 11 in a pixel portion by a normal LSI process. At the same time, a peripheral circuit is formed.

FIG. 13C shows that the above-mentioned element formation surface is made of Si.
The support substrate 13 such as
This is the step of bonding.

FIG. 13D shows a step of removing the back surface of the single crystal Si substrate 1 to the isolation insulating film 102 by grinding, polishing, and etching. At this time, the isolation insulating film 102 allows the single crystal Si substrate 1 to be thinned with high accuracy.

FIG. 13E shows the single crystal Si substrate 1 described above.
Is a step of bonding a transparent support substrate 15 made of glass or the like to the back surface of the substrate with a bonding layer 14 made of an organic adhesive or the like.

FIG. 13F shows the supporting substrate 13 and the bonding layer 1.
In this step, the bonding layer 12 is removed by O ₂ plasma etching. The liquid crystal display device is completed by combining this liquid crystal display array with a counter substrate having a transparent conductor with liquid crystal interposed therebetween.

As described above, in the above-described manufacturing method, the switching element of the pixel and the peripheral circuit element Poly
-Simultaneously form the Si TFT on the single crystal Si substrate,
Since the method is transferred to a transparent substrate, a conventional semiconductor manufacturing apparatus and process conditions can be applied, and a liquid crystal display array integrated with peripheral circuits can be formed.

[0013]

As described above, in the conventional method of manufacturing a liquid crystal display array, a single crystal Si substrate is not used as a transistor forming material, and a transistor (hereinafter referred to as a MOS) formed from a single crystal Si substrate is not used. Transistor) has a mobility of 1000 cm2 / VS
Mobility of SiTFT 100cm2 / V · S or a-SiT
10 to 100 compared to FT mobility of 1 cm2 / VS
Despite being about twice as high and excellent in terms of reproducibility and reliability, there was a problem that the single crystal Si substrate was not sufficiently utilized. In response to higher performance, the peripheral circuits need to operate at higher speed. However, there is a problem that the current TFT performance cannot sufficiently cope with future high-speed operation.

Further, it is possible to form a MOS transistor, a pixel electrode, and the like on a single-crystal Si substrate using ordinary semiconductor manufacturing equipment and process conditions.
The substrate itself is opaque, and in order to use it as a liquid crystal display array, it is necessary to make the substrate transparent including the pixel electrode portion, and there has been a problem that these means have not been established.

The present invention has been made in order to solve such a problem, and a general semiconductor manufacturing apparatus and process conditions can be applied. A switching element of a pixel and its peripheral circuit element are constituted by MOS transistors. It is an object of the present invention to provide a method for manufacturing a liquid crystal display array.

[0016]

According to a first aspect of the present invention, there is provided a method of manufacturing a liquid crystal display array , wherein a groove is formed in a single crystal Si substrate.
Forming and filling the grooves with glass;
Forming a MOS transistor on the single crystal Si substrate
Forming a transparent pixel electrode in the glass-filled portion
And the glass-filled portion exposes the back surface of the single-crystal Si substrate
And removing the transparent substrate through the single crystal Si substrate.
And joining the bright support substrate .

[0017]

According to a second aspect of the present invention, there is provided a method of manufacturing a liquid crystal display array, comprising the steps of: forming a groove in a single crystal Si substrate;
Filling the groove with glass, forming a MOS transistor on the single-crystal Si substrate, and bonding a transparent support substrate to a surface on which the MOS transistor is formed;
Removing a back surface of the single crystal Si substrate until the glass filling portion is exposed; and forming a transparent pixel electrode in the glass filling portion on the back surface of the single crystal Si substrate.

According to a third aspect of the present invention, there is provided a method for manufacturing a liquid crystal display array, comprising the steps of: forming a groove in a single crystal Si substrate;
A step of filling the groove with glass, a step of bonding a transparent support substrate to the glass filling part, and a step of removing the back surface of the single crystal Si substrate until the glass filling part is exposed,
Forming a MOS transistor on the single-crystal Si substrate; and forming a transparent pixel electrode on the glass-filled portion.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a liquid crystal display array, comprising the steps of: forming an etching stopper layer having a lower etching rate than Si inside a single crystal Si substrate; Forming a MOS transistor in a crystalline Si portion;
Removing a portion of the single-crystal Si other than the transistor formation portion to the etching stopper layer to form a groove, forming a transparent pixel electrode in the groove, and bonding a transparent support substrate to the element formation surface; Removing the back surface of the single crystal Si substrate up to the etching stopper layer.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a liquid crystal display array, comprising: forming an etching stopper layer having a lower etching rate than Si inside a single crystal Si substrate; Forming a MOS transistor in a crystalline Si portion, forming a transparent pixel electrode, bonding a transparent support substrate to the element forming surface, and removing the back surface of the Si substrate to the etching stopper layer; Removing the etching stopper layer and the single-crystal Si portion of the transparent pixel electrode portion.

According to a sixth aspect of the present invention, in the method of manufacturing a liquid crystal display array according to the fourth or fifth aspect , the etching rate in the single crystal Si substrate is lower than that of Si. The step of forming the etching stopper layer is performed by ion implantation of B, O, and N.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a liquid crystal display array, comprising the steps of: forming a groove in a single crystal Si substrate;
Forming an etching stopper layer having an etching rate lower than that of Si in the groove;
forming a MOS transistor in the i-portion, forming a transparent pixel electrode in the groove, bonding a transparent support substrate to the element forming surface, and removing the back surface of the single crystal Si substrate to the etching stopper layer And the step of performing.

According to a eighth aspect of the present invention, there is provided a method of manufacturing a liquid crystal display array, comprising the steps of: forming a MOS transistor on a single crystal Si substrate; forming a transparent pixel electrode; Forming a transparent support plate, and a step of bonding a single crystal Si of the transparent pixel electrode portion.
The method includes a step of forming a cavity by removing the substrate, and a step of filling the cavity with a transparent sealing agent.

According to a ninth aspect of the present invention, there is provided a method of manufacturing a liquid crystal display array, comprising the steps of: forming a MOS transistor on a single-crystal Si substrate; forming a transparent pixel electrode; And the step of joining a transparent support substrate with a transparent conductor to be a counter electrode,
The method includes a step of forming a cavity by removing the single crystal Si substrate of the transparent pixel electrode portion, and a step of injecting liquid crystal into the cavity.

According to a tenth aspect of the present invention, in the method for manufacturing a liquid crystal display array according to the eighth or ninth aspect , etching is performed between the transparent pixel electrode and the single crystal Si substrate. The method includes a step of providing a sacrificial layer for guiding a liquid.

According to the eleventh aspect of the present invention, there is provided a method of manufacturing a liquid crystal display array according to the tenth aspect.
In the method, the MOS transistor uses a single crystal Si substrate.
The transparent pixel electrode is formed using a transparent pixel electrode portion.
Liquid crystal is injected from the removed part of the single crystal part of
The single-crystal Si substrate may be a gap spacer with respect to a counter substrate defining a liquid crystal cell thickness or a pixel separation wall.

[0028]

The liquid crystal display array according to claim 1 of the present invention is manufactured.
In the fabrication method, a groove is formed in a single-crystal Si substrate and filled with glass.
And a transparent pixel electrode is formed in the glass filling part
Therefore, after the thinning of the single crystal Si substrate, the MOS transistor
A single-crystal Si part with a transparent pixel electrode
Glass filling part can be separated.

[0029]

In the method of manufacturing a liquid crystal display array according to a second aspect of the present invention, similarly to the method of manufacturing a liquid crystal display array of the first aspect , a groove is formed in a single crystal Si substrate to fill the glass, and the glass is filled. Since the transparent pixel electrode is formed in the portion, the single crystal Si portion in which the MOS transistor is formed and the glass filling portion in which the transparent pixel electrode is formed can be separated after thinning the single crystal Si substrate.

In the method of manufacturing a liquid crystal display array according to a third aspect of the present invention, similarly to the method of manufacturing a liquid crystal display array of the first or second aspect , a groove is formed in a single crystal Si substrate and glass is filled. Since the transparent pixel electrode is formed in the glass-filled portion, the single-crystal Si portion where the MOS transistor is formed and the glass-filled portion where the transparent pixel electrode is formed can be separated after the thinning of the single crystal Si substrate.

In the method of manufacturing a liquid crystal display array according to a fourth aspect of the present invention, an etching stopper layer having a lower etching rate than that of Si is formed in a single crystal Si substrate, and a single crystal Si portion above the etching stopper layer is formed. MOS
Since a transistor is formed and the remaining portion is removed to the etching stopper layer to form a groove, the single crystal S
When thinning the i-substrate, the film thickness can be controlled with high accuracy.

In the method of manufacturing a liquid crystal display array according to a fifth aspect of the present invention, an etching stopper layer having a lower etching rate than that of Si is formed in a single crystal Si substrate, and a single crystal Si portion above the etching stopper layer is formed. MOS
Since the transistor and the transparent pixel electrode are formed, after bonding the transparent support substrate, the portion of the Si where the transparent pixel electrode is to be formed is formed.
Can be accurately removed.

In the method for manufacturing a liquid crystal display array according to a sixth aspect of the present invention, an etching stopper layer having a lower etching rate than that of Si is formed inside a single crystal Si substrate by ion implantation of B, O, and N. be able to.

In the method of manufacturing a liquid crystal display array according to a seventh aspect of the present invention, a groove is formed in a single crystal Si substrate, and an etching stopper layer having a lower etching rate than Si and a transparent pixel electrode are formed in the groove. Therefore, the thickness of the single-crystal Si substrate can be accurately controlled after joining the transparent support substrate.

In the method for manufacturing a liquid crystal display array according to the eighth aspect of the present invention, after the single crystal Si substrate is thinned, the transparent support substrate is joined, and the single crystal Si of the transparent pixel electrode portion is removed to form a cavity. Since the pixel portion is formed and the cavity is filled with a transparent sealing agent, the pixel portion can be made transparent.

In a method of manufacturing a liquid crystal display array according to a ninth aspect of the present invention, after a single-crystal Si substrate is thinned, a transparent support substrate with a transparent conductor serving as a counter electrode is joined to form a single pixel of the transparent pixel electrode portion. Since a cavity is formed by removing crystal Si and liquid crystal is injected into the cavity, a liquid crystal display array having a transparent pixel portion can be formed.

According to a tenth aspect of the present invention, in the method for manufacturing a liquid crystal display array according to the eighth or ninth aspect , an etching solution is provided between the transparent pixel electrode and the single crystal Si substrate. Since the guiding sacrifice layer is provided, single crystal Si in the transparent pixel electrode portion can be accurately removed.

[0039] In the method of manufacturing a liquid crystal display array according to claim 11 of the present invention, the production of liquid crystal display array according to claim 10
In the method, a single-crystal Si substrate is used as a gap spacer for the liquid crystal cell thickness and a counter substrate for defining the thickness of the liquid crystal cell, or as a pixel separation wall. Electric field interference from the pixel electrode can be prevented.

[0040]

【Example】

Embodiment 1 FIG. 1A and 1B are a sectional view and a plan view, respectively, showing an embodiment of the present invention. In FIG. 1A, reference numeral 1 denotes a single crystal Si substrate including a channel region;
A MOS transistor is formed on this single crystal Si substrate 1. Reference numeral 2 denotes a gate insulating film of a MOS transistor made of Si ₃ N ₄ , SiO _2, etc., and 3 denotes Si, Al, Mo, T
Gate electrodes of MOS transistors made of i, W, Ta, Cr, Cu, etc., and source and drain regions of MOS transistors formed by injecting impurities such as P, B, As, etc. into the single crystal Si substrate 1 , 9, and 10 are Si, Al, M
These are the source and drain electrodes of a MOS transistor made of o, Ti, W, Ta, Cr, Cu, or the like. Reference numeral 30 denotes a glass formed adjacent to the MOS transistor described above and separated by a barrier film 20 made of a Si thermal oxide film or the like. On this glass 30, a storage capacitor electrode 6 made of a transparent ITO or the like is formed. ₃ N ₄ , SiO ₂ , Al ₂ O ₃ , Ta ₂ O
_The storage capacitor film 7 made of _{5 and the} like and the transparent pixel electrode 8 made of ITO and the like are sequentially laminated to form a storage capacitor element. 11 is a MOS transistor made of Si ₃ N ₄ , SiO ₂ , Al ₂ O ₃ , Ta ₂ O ₅ or the like and a protective film on the surface of the storage capacitor element, and 14 is a single crystal Si made of a transparent organic adhesive such as acryl or epoxy. A bonding layer formed on the back surface of the substrate 1 and the surface of the barrier layer 20.
The single crystal Si substrate 1 on which the OS transistor is formed and the glass 30 on which the transparent pixel electrode 8 is formed are formed on the transparent support substrate 1.
5.

In FIG. 1B, AA ′ corresponds to FIG.
The cross-sectional line of FIG. In this embodiment, since the storage capacitor electrode 6 is formed of transparent ITO, there is no influence on the aperture ratio, and the size is almost the same as the transparent pixel electrode 8. However, if the storage capacitor electrode 6 is opaque. Al,
When formed from a metal such as Ta or Cr, the size must be minimized to suppress a decrease in aperture ratio. Although the adhesive layer 14 and the glass 30 are transparent, they do not necessarily mean completely colorless and transparent, and may be colored red, green, and blue. in this case,
When a color liquid crystal display device is manufactured, it is possible to eliminate the need to newly provide a color filter.

Next, a method for manufacturing the above-described liquid crystal display array will be described. 2A to 2H are cross-sectional views illustrating a method of manufacturing a liquid crystal display array according to the present embodiment.
FIG. 2A shows that a groove is formed in the single-crystal Si substrate 1 by grinding, etching, or the like, and the surface is formed by thermal oxidation, CVD, or the like.
This is a step of forming the barrier film 20 made of iO ₂ , and the barrier film 20 prevents impurities in the glass filling the above-described trench from diffusing into the single-crystal Si substrate 1.

FIG. 2B shows that, for example, Si-B
This is a step of depositing and filling a high melting point glass 30 having a high heat resistance of 800 ° C. or higher such as —O, and it is necessary to select a glass that can withstand a MOS transistor forming step in a later step.

FIG. 2C shows a step of grinding and polishing the surface of the above-mentioned glass 30 until the surface of the single crystal Si substrate 1 is exposed, and the glass 30 is filled by this step. A single crystal Si substrate 1 is obtained.

FIG. 2D shows that a MOS transistor is formed on the exposed portion of the single crystal Si substrate 1 and a transparent pixel electrode and the like are formed on the glass 30 by using a normal semiconductor manufacturing apparatus and process conditions. The use of a thermal oxide film formed at 950 ° C. or higher for the gate insulating film 2 of the MOS transistor is more excellent in reproducibility and reliability. Also,
Although the protective film 11 is shown as flattened in the drawing, this is not the case when an organic adhesive, low melting point glass, or the like is used.

FIG. 2 (e) shows that the S
i, a support substrate 13 made of quartz, glass, or the like is joined by a joining layer 12 made of an organic adhesive such as acrylic or epoxy. Other joining methods include anodic joining, solder joining, and low-melting glass joining. However, in this manufacturing method, since the bonding layer 12 and the support substrate 13 are removed in a later step, it is desirable to use an organic adhesive which is easily removed.

FIG. 2F shows a step of etching, grinding, or polishing the back surface of the single-crystal Si substrate 1 until the transparent grooves of the barrier film 20 and the glass 30 are exposed. In this step, in particular, CMP (Chemical and Chemical) processes are performed. Mechanical Polish
ing: chemical mechanical polishing), the single crystal Si substrate 1 can be thinned with high accuracy.

FIG. 2 (g) shows a transparent support substrate 15 made of quartz, glass, plastic or the like on the back surface of the above-mentioned single crystal Si substrate 1 with a bonding layer 14 made of a transparent organic adhesive such as acryl or epoxy. This is a bonding step, and other bonding methods include anodic bonding and low-melting glass bonding. Here, the necessary condition is that the bonding layer 14 is transparent.

FIG. 2H shows a step of removing the support substrate 13 and the bonding layer 12 until the protective film 11 is exposed. The bonding layer 12 can be removed by a solvent, O ₂ plasma etching or the like. . Through the above steps, a liquid crystal display array is completed.

Embodiment 2 FIG. FIGS. 3A and 3B are cross-sectional views of another liquid crystal display array formed by the manufacturing method of the first embodiment. FIG. 3 (a), (b)
Is an example in which light-shielding films are provided on the upper and lower portions of a MOS transistor in order to prevent a light leak current. FIG. 3 (a)
Are formed on the protection film 11 of the MOS transistor and the single crystal S
The light shielding films 90 and 91 are provided on the back surface of the i-substrate 1. FIG.
And light-shielding films 90 and 92 are provided thereon. Light shielding film 9
As long as 0, 91, and 92 have a light-shielding property, they may be insulators, conductors, inorganic substances, or organic substances. However, in consideration of reducing the parasitic capacitance of the MOS transistor and preventing short-circuiting of the MOS transistor. An insulator is preferred. As an insulator having a light-shielding property, black Pr
MnO ₃ and an organic substance include a resin containing a black pigment. In the following embodiments, the light shielding film can be applied in the same manner as in this embodiment.

Embodiment 3 FIG. FIGS. 4A and 4B are cross-sectional views illustrating a method for manufacturing another liquid crystal display array. FIG.
The manufacturing process up to (a) is the same as that shown in FIG.
2 to (f), but the shape is obtained by inverting the shape of FIG. Reference numeral 14 denotes a bonding layer made of a transparent organic adhesive such as acrylic or epoxy, and reference numeral 15 denotes a transparent support substrate made of quartz, glass, plastic, or the like.

FIG. 4 (b) shows the relationship between Si, Al, Mo, Ti,
Second drain electrode 1 made of W, Ta, Cr, Cu, etc.
6. Pixel electrode 17 made of transparent ITO or the like, Si ₃ N ₄ ,
This is a step of forming a protective film 18 made of SiO ₂ , Al ₂ O ₃ , Ta ₂ O ₅ or the like. Through the above steps, a liquid crystal display array is completed. In this embodiment, a step of forming the pixel electrode 17 and the like on the back surface of the single crystal Si substrate 1 is added.
There is an advantage that the process of bonding the supporting substrate only needs to be performed once.

Embodiment 4 FIG. FIG. 5 is a sectional view of another liquid crystal display array formed by the manufacturing method of the third embodiment. In the present embodiment, FIG.
In this step, only the MOS transistor is formed, and the source and drain electrodes 9 and 10, the storage capacitor electrode 6, and the storage capacitor film 7 are formed on the back surface of the single crystal Si substrate 1. With such a configuration, the gate wiring 3 and the source wiring 9 are formed separately on the front and back surfaces of the single-crystal Si substrate 1, so that there is an advantage that there is no fear of a short circuit.

Embodiment 5 FIG. 6A to 6F are cross-sectional views illustrating another method of manufacturing a liquid crystal display array. FIG.
(A) shows a case where a groove is formed in a single crystal Si substrate 1 by grinding, etching, or the like, and the surface thereof is thermally oxidized, or a Si is formed by CVD or the like.
This is a step of forming a barrier film 20 made of O ₂ , and the barrier film 20 prevents the impurities in the glass filling the above-described grooves from diffusing into the single-crystal Si substrate 1.

FIG. 6B shows that, for example, Si-B
This is a step of depositing and filling a high-melting glass 30 having a high heat resistance of 800 ° C. or higher, such as —O, and it is necessary to select a glass that can withstand a MOS transistor forming step in a later step.

FIG. 6C shows a process in which a transparent support substrate 15 made of quartz or the like is joined to the glass 30 by pressing, heating and melting to join the glass.
It must be able to withstand the S transistor formation process.

FIG. 6D shows a step of etching, grinding, or polishing the back surface of the single crystal Si substrate 1 until the transparent groove filled with the barrier film 20 and the glass 30 is exposed.

FIG. 6 (e) shows the above-mentioned substrate turned upside down,
This is a step of forming a MOS transistor on an exposed portion of the single crystal Si substrate 1 embedded in the glass 30.

FIG. 6F shows that the storage capacitor electrode 6, the storage capacitor film 7, the transparent pixel electrode 8,
This is a step of forming the protective film 11 and the like.

Embodiment 6 FIG. 7A to 7G are cross-sectional views illustrating a method for manufacturing another liquid crystal display array. FIG.
(A) is a step of forming an etching stopper layer 21 in the single crystal Si substrate 1. In this embodiment, the etching stopper layer 21 is formed from a high concentration B layer by B ion implantation. The high concentration B layer has an acceleration voltage of 200 keV
Is formed over the region of 600 nm to 800 nm from the surface of the single crystal Si substrate 1 with an ion concentration of 10 ²⁰ / cm ³ or more. High concentration of B
Is implanted, single crystal Si through which B ions have passed
Since a defect occurs in the substrate 1, the defect is recovered by a heat treatment thereafter. In addition, as a method of forming an etching stopper layer, there is a method of forming a SiO ₂ layer and a Si ₃ N ₄ layer in a single crystal Si substrate by ion implantation of O, N, or the like.

FIG. 7B shows a step of forming a MOS transistor in the single-crystal Si portion above the above-mentioned etching stopper layer 21, wherein 2 is a gate insulating film, 3 is a gate electrode, 4 and 5 are sources, This is a drain region.

FIG. 7C shows a step of forming a groove by removing the single-crystal Si portion above the etching stopper layer 21 where the transparent pixel electrode 8 is to be formed up to the etching stopper layer 21. Note that the steps of FIGS. 7B and 7C can be performed in reverse order.

FIG. 7D shows a step of forming the transparent pixel electrode 8, the storage capacitor electrode 6, the protective film 11 and the like in the above-mentioned groove.

FIG. 7E shows a step of bonding the transparent support plate 15 to the above-described element forming surface by the bonding layer 14.

FIG. 7F shows a step of removing the back surface of the single crystal Si substrate 1 to the etching stopper layer 21. In this case, first, the single crystal Si substrate 1 is ground and polished while leaving the Si layer from the etching stopper layer 21 by about 20 to 30 μm, and then the remaining Si layer is removed by wet etching. At this time, the high concentration B layer functions as the etching stopper layer 21. TMAH as an etchant
When (Tetramethyl ammoniumhydroxide: (CH ₃ ) ₄ NOH) is used, the single-crystal Si substrate 1 can be used as a high concentration B layer having
Etching can be performed at a speed of about 0 times. Other etchants include KOH and EDP (Ethlene Diam).
ine Pyrocatechol). The reason why grinding and polishing are used together when removing the back surface of the single crystal Si substrate 1 is to shorten the etching time. The same applies to the case where the etching stopper layer 21 is composed of a SiO ₂ layer and a Si ₃ N ₄ layer.

FIG. 7 (g) shows that the etching stopper layer 21 composed of the high-concentration B layer is removed by dry etching such as SF ₆ or CF ₄ plasma to obtain Si ₃ N ₄ , SiO ₂ and Al ₂ O.
₃ , a step of forming a protective film 18 made of Ta ₂ O ₅ or the like. When the etching stopper layer 21 is made of SiO ₂ or Si ₃ N _4, this step is unnecessary because the etching stopper layer 21 can be used as a protective film.

Embodiment 7 FIG. 8A to 8G are cross-sectional views illustrating another method for manufacturing a liquid crystal display array. FIG.
(A) is a step of forming an etching stopper layer 22 in the single-crystal Si substrate 1, and the etching stopper layer 22 is formed from a high-concentration B layer by B ion implantation. When high-concentration B ion implantation is performed, a defect occurs in the single-crystal Si substrate 1 in a portion where B ions have passed.
The defect is recovered by a subsequent heat treatment. Other methods for forming the etching stopper layer include O,
There is a method of forming a SiO ₂ layer and a Si ₃ N ₄ layer by ion implantation of N or the like.

Instead of forming the etching stopper layer 22 on the single-crystal Si substrate 1, an SOI substrate (Silicon on Insulator) formed by laminating a single-crystal Si substrate can be used. The bonded SOI substrate is made of single crystal Si
The substrate is bonded to a single-crystal Si substrate whose surface has been thermally oxidized by applying an electric field, heating, or the like, and the back surface of one of the single-crystal Si substrates is ground and polished to be thin. At this time, the insulating layer of the SOI substrate becomes the etching stopper layer 22. The thickness of the thinned single-crystal Si substrate may correspond to the thickness of the liquid crystal, for example, 1 to 15 μm.

FIG. 8B shows a step of forming the gate insulating film 2 by thermal oxidation.

FIG. 8C shows a step of forming a MOS transistor, a storage capacitor, a transparent pixel electrode 8, a protective film 11, and the like.

FIG. 8D shows a step of bonding the transparent support plate 15 to the element forming surface by the bonding layer 14.

FIG. 8E shows a step of removing the back surface of the single crystal Si substrate 1 to the etching stopper layer 22 by grinding, polishing, and wet etching.

FIG. 8F shows a step of removing the etching stopper layer 22 and the single crystal Si substrate 1 in the transparent pixel electrode 8 by etching. At this time, the gate insulating film 2 functions as an etching stopper layer.

FIG. 8G shows a step of forming an insulating film 26 around the single crystal Si substrate 1 in the MOS transistor formation portion. This insulating film 26 prevents DC current from leaking from the single crystal Si substrate 1 into the liquid crystal.

In this embodiment, when an SOI substrate is used, the single-crystal Si substrate can be left thick by controlling the grinding and polishing. Therefore, the single-crystal Si substrate is used as a gap spacer with respect to the counter substrate which defines the thickness of the liquid crystal cell. Can be used.
When the single-crystal Si substrate is left in the gate wiring and the source wiring, it can be used as a barrier for preventing electric field interference from a pixel electrode between adjacent pixels.

Embodiment 8 FIG. FIGS. 9A to 9C are cross-sectional views illustrating a method for manufacturing another liquid crystal display array. FIG.
(A): A step of forming a groove having a depth of 1 to several tens μm in a portion where a transparent pixel electrode 8 is to be formed on a single-crystal Si substrate 1 and forming a gate insulating film 2 made of a thermal oxide film or the like thereon. It is.

FIG. 9B shows single crystal Si other than the above-described grooves.
In this step, a MOS transistor is formed in the portion of the substrate 1, and the transparent pixel electrode 8, the storage capacitor, the protective film 11, and the like are formed in the above-described groove.

FIG. 9C shows that the transparent support plate 15 is bonded to the above-described element forming surface side by a bonding layer 14 made of a transparent adhesive.
In this step, the single crystal Si substrate 1 is ground and polished from the back surface and removed until the transparent groove is exposed. In particular, when CMP is used for grinding and polishing, it is possible to reduce the thickness of the single crystal Si substrate 1 with high accuracy. At this time, the gate insulating film 2 in the groove functions as an etching stopper layer. Thus, the liquid crystal display array is completed. Further, in the present embodiment, the gate insulating film 2 is also used as the etching stopper layer, but this may be provided separately.

Embodiment 9 FIG. 10A to 10C are cross-sectional views illustrating a method for manufacturing another liquid crystal display array. FIG.
1A shows a MOS transistor on a single-crystal Si substrate 1 and a storage capacitor electrode 6, a storage capacitor film 7, a transparent pixel electrode 8 on a sacrificial layer 23 made of Poly-Si or the like with a gate insulating film 2 interposed therebetween. This is a step of forming the protective film 11 and the like.

FIG. 10B shows that the back surface of the single-crystal Si substrate 1 is ground and polished to a thickness of 1 to several tens μm,
Are bonded by a bonding layer 14 made of a transparent adhesive or the like, an etching hole 19 is formed around the transparent pixel electrode 8, and the single crystal Si under the transparent pixel electrode 8 is
This is a step of removing the substrate 1 using an anisotropic etching solution. At this time, the etching hole 19 is preferably provided on the sacrificial layer 23. The sacrifice layer 23 plays a role of guiding the etchant inside. TMAH (Te
tramethyl ammonium hydroxide: (CH ₃ ) ₄ NOH) or KO
H, EDP (Ethlene Diamine Pyrocatechol) and the like, and laser-induced selective etching using a mixed solution of phosphoric acid and KOH is also possible.

FIG. 10C shows the single crystal Si substrate 1 described above.
This is a step of filling a transparent encapsulant 24 made of acrylic, epoxy resin, or the like into the cavity after removing the resin. The transparent sealant 24 does not necessarily mean completely colorless and transparent, and may be colored red, green, and blue. in this case,
When manufacturing a color liquid crystal display device, it is not necessary to newly provide a color filter.

Embodiment 10 FIG. 11A to 11C are cross-sectional views illustrating a method for manufacturing another liquid crystal display array. FIG.
1 (a) shows a MOS transistor on a single-crystal Si substrate 1, a storage capacitor electrode 6, a storage capacitor film 7, and a transparent pixel electrode 8 on a sacrificial layer 23 made of Poly-Si or the like with a gate insulating film 2 interposed therebetween. Forming the protective film 11 and the like.

FIG. 11 (b) shows that the back surface of the single crystal Si substrate 1 is ground and polished to a thickness of 1 to several tens μm corresponding to the liquid crystal thickness, and the transparent conductor 25 made of ITO or the like is formed. The support plate 15 is joined with a joining layer 14 made of an organic adhesive such as acrylic or epoxy, an etching hole 19 is formed around the transparent pixel electrode 8, and a single hole below the transparent pixel electrode 8 is formed using the etching hole 19. This is a step of removing the crystalline Si substrate 1 with an anisotropic etching solution. At this time, the etching holes 19
Is preferably provided on the sacrificial layer 23. Further, the transparent support substrate 15 also serves as an opposing substrate when a liquid crystal cell is formed.
The i-substrate 1 is used as a gap spacer with an opposing substrate that defines the thickness of the liquid crystal cell.

FIG. 11 (c) shows the liquid crystal 27 in the above-mentioned cavity.
And sealing the surface of the protective film 11 with a transparent sealing agent 24 made of resin or the like. Thus, the liquid crystal display array is completed.

As described above, in the first to tenth embodiments,
Although only the pixel section has been described, the MOS of the peripheral circuit element
The transistors are basically the same as those described above except that it is necessary to form both n-type and p-type transistors, there is no need to form a transparent pixel electrode, a storage capacitor element, etc., and there is no need to form a groove or the like. It can be formed by a similar structure and manufacturing method. Although the bonding layer 14 is formed over the entire surface, the bonding layer 14 may not be provided at the portion where the transparent pixel electrode 8 is located. In this case, the bonding layer 14 does not need to be transparent.

[0086]

According to a first aspect of the present invention, there is provided a method of manufacturing a liquid crystal display array , comprising forming a groove in a single crystal Si substrate,
To form a transparent pixel electrode in the glass-filled area
Therefore, after thinning the single crystal Si substrate,
Single-crystal Si part with a transistor formed and transparent pixel electrode formed
This has the effect that the filled glass filling portion can be separated.

[0087]

A method of manufacturing a liquid crystal display array according to a second aspect of the present invention is similar to the method of manufacturing a liquid crystal display array of the first aspect , wherein a groove is formed in a single-crystal Si substrate and glass is filled.
Because a transparent pixel electrode is formed in the glass filling part,
After thinning the single crystal Si substrate, the single crystal Si portion where the MOS transistor is formed and the glass filled portion where the transparent pixel electrode is formed can be separated.

The method of manufacturing a liquid crystal display array according to a third aspect of the present invention is similar to the method of manufacturing a liquid crystal display array of the first or second aspect , wherein a groove is formed in a single crystal Si substrate and glass is filled. Since the transparent pixel electrode is formed in the glass-filled portion, after the thinning of the single-crystal Si substrate, the single-crystal Si portion in which the MOS transistor is formed and the glass-filled portion in which the transparent pixel electrode is formed can be separated. It works.

According to a fourth aspect of the present invention, in the method of manufacturing a liquid crystal display array, an etching stopper layer having a lower etching rate than that of Si is formed in a single crystal Si substrate, and a single crystal Si portion above the etching stopper layer is formed. Since a MOS transistor is formed on the substrate and the remaining portion is removed to the etching stopper layer to form a groove,
When the thickness of the substrate is reduced, the thickness can be controlled with high accuracy.

According to a fifth aspect of the present invention, in a method of manufacturing a liquid crystal display array, an etching stopper layer having a lower etching rate than that of Si is formed in a single crystal Si substrate, and a single crystal Si portion above the etching stopper layer is formed. Since the MOS transistor and the transparent pixel electrode are formed at the same time, there is an effect that, after bonding the transparent support substrate, Si in the portion where the transparent pixel electrode is formed can be accurately removed.

In the method of manufacturing a liquid crystal display array according to the sixth aspect of the present invention, an etching stopper layer having a lower etching rate than that of Si is formed inside a single crystal Si substrate by ion implantation of B, O, and N. It has the effect of being able to do so.

According to a method of manufacturing a liquid crystal display array according to a seventh aspect of the present invention, a groove is formed in a single crystal Si substrate, and an etching stopper layer and a transparent pixel electrode having a lower etching rate than Si are formed in the groove. Therefore, there is an effect that the film thickness of the single crystal Si substrate can be accurately controlled after bonding the transparent support substrate.

In the method for manufacturing a liquid crystal display array according to the eighth aspect of the present invention, after the single crystal Si substrate is thinned, the transparent support substrate is joined, and the single crystal Si of the transparent pixel electrode portion is removed to form a cavity. Since it is formed and its cavity is filled with a transparent sealant, the pixel portion can be made transparent.

According to a method of manufacturing a liquid crystal display array according to a ninth aspect of the present invention, after a single-crystal Si substrate is thinned, a transparent support substrate with a transparent conductor serving as a counter electrode is joined to form a single pixel of the transparent pixel electrode portion. Since the crystal Si is removed to form a cavity and the liquid crystal is injected into the cavity, an effect is obtained in that a liquid crystal display array in which the pixel portion is transparent can be formed.

According to a tenth aspect of the present invention, in the method for manufacturing a liquid crystal display array according to the eighth or ninth aspect , an etching solution is provided between the transparent pixel electrode and the single crystal Si substrate. Since the method includes the step of providing the guiding sacrifice layer, there is an effect that single crystal Si in the transparent pixel electrode portion can be removed with high accuracy.

The method for manufacturing a liquid crystal display array according to claim 11 of the present invention is the method for manufacturing a liquid crystal display array according to claim 10.
In the method, the MOS transistor uses a single crystal Si substrate.
The transparent pixel electrode is formed using a transparent pixel electrode portion.
Liquid crystal is injected from the removed part of the single crystal part of
Since the single-crystal Si substrate is used as a gap spacer or a pixel separation wall with the counter substrate that defines the thickness of the liquid crystal cell, there is no need to newly provide a gap spacer, and the electric field from the pixel electrode between adjacent pixels is eliminated. This has the effect of preventing interference.

[Brief description of the drawings]

FIG. 1 is a sectional view and a plan view of a liquid crystal display array according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view illustrating a method for manufacturing a liquid crystal display array according to Embodiment 1 of the present invention.

FIG. 3 is a sectional view of a liquid crystal display array according to Embodiment 2 of the present invention.

FIG. 4 is a cross-sectional view illustrating a method for manufacturing a liquid crystal display array according to Embodiment 3 of the present invention.

FIG. 5 is a sectional view illustrating a method for manufacturing a liquid crystal display array according to Embodiment 4 of the present invention.

FIG. 6 is a sectional view illustrating a method for manufacturing a liquid crystal display array according to Embodiment 5 of the present invention.

FIG. 7 is a sectional view illustrating a method for manufacturing a liquid crystal display array according to Embodiment 6 of the present invention.

FIG. 8 is a sectional view illustrating a method for manufacturing a liquid crystal display array according to Embodiment 7 of the present invention.

FIG. 9 is a sectional view illustrating a method for manufacturing a liquid crystal display array according to Embodiment 8 of the present invention.

FIG. 10 is a sectional view illustrating a method for manufacturing a liquid crystal display array according to Embodiment 9 of the present invention.

FIG. 11 is a sectional view illustrating a method for manufacturing a liquid crystal display array according to Embodiment 10 of the present invention.

FIG. 12 is a cross-sectional view and a plan view of a conventional liquid crystal display array.

FIG. 13 is a cross-sectional view illustrating a method for manufacturing a conventional liquid crystal display array.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Single crystal Si substrate, 2 gate insulating films, 3 gate electrodes, 4 source regions, 5 drain regions, 6 storage capacitance electrodes, 7 storage capacitance films, 8 transparent pixel electrodes, 9 source electrodes, 10 drain electrodes, 11 protective films, Reference Signs List 12 bonding layer, 13 supporting substrate, 14 bonding layer, 15 transparent supporting substrate, 16 second drain electrode, 17 pixel electrode, 18
Protective film, 19 etching hole, 20 barrier film, 21,
22 etching stopper layer, 23 sacrificial layer, 24 transparent sealant, 25 transparent conductor, 26 insulating film, 27 liquid crystal,
30 glass, 90, 91, 92 light shielding film, 101 channel, 102 isolation insulating film, 104 source, 105
drain.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshinori Iwasa 8-1-1, Tsukaguchi Honcho, Amagasaki City Inside the Materials and Devices Laboratory, Mitsubishi Electric Corporation (72) Inventor Kazuhisa Takahashi 8-1-1, Tsukaguchi Honmachi, Amagasaki City (72) Inventor, Muneto Kumagai 1-1-1, Tsukaguchi-Honcho, Amagasaki-shi In-house, Materials and Devices Laboratory Mitsubishi Electric Corporation (72) Inventor, Hisatoshi Kurusumi 8-chome, Tsukaguchi-Honcho, Amagasaki-shi No. 1-1 Mitsubishi Electric Corporation Material Device Research Laboratory (72) Inventor Hirofumi Namisaki 8-1-1 Tsukaguchi Honcho, Amagasaki City Mitsubishi Electric Corporation Material Device Research Laboratory (56) References 273797 (JP, A) JP-A-63-101832 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1368 H01L 21/336 H01L 27/12 H01L 29/786

Claims (11)

(57) [Claims] A step of forming a groove in a single-crystal Si substrate;
Filling the groove with glass, and the single crystal Si substrate
Forming a MOS transistor on the substrate;
Forming a transparent pixel electrode in the filling portion;
A process for removing the back surface of the substrate until the glass filling portion is exposed.
And bonding a transparent support substrate to the back surface of the single crystal Si substrate.
Manufacturing a liquid crystal display array, comprising the steps of:
Method. 2. A step of forming a groove in a single crystal Si substrate;
Filling the groove with glass, and the single crystal Si substrate
Forming a MOS transistor in the MOS transistor;
Bonding a transparent support substrate to the formation surface of the transistor,
The glass filling portion is exposed on the back surface of the single crystal Si substrate.
And removing the gas on the back surface of the single crystal Si substrate.
Forming a transparent pixel electrode in the lath filling portion . Forming a groove in the single crystal Si substrate;
A step of filling the groove with glass; and
Bonding a transparent support substrate, and backing the single crystal Si substrate.
Removing the surface until the glass filling portion is exposed,
Forming a MOS transistor on the single crystal Si substrate
Forming a transparent pixel electrode in the glass-filled portion
And a method for manufacturing a liquid crystal display array. 4. The method according to claim 1, wherein the inside of the single crystal Si substrate has an air
Forming an etching stopper layer with low etching speed
Process and a single-crystal Si portion on the etching stopper layer
Forming a MOS transistor separately;
A part of the single-crystal Si other than the transistor forming portion is
Removing the etching stopper layer to form a groove,
Forming a transparent pixel electrode in the groove; and forming the element.
Bonding a transparent support substrate to the surface;
Removing the back surface of the plate to the etching stopper layer;
A method for manufacturing a liquid crystal display array, comprising: 5. The method according to claim 1, wherein the inside of the single crystal Si substrate has an energy
Forming an etching stopper layer with low etching speed
Process and a single-crystal Si portion on the etching stopper layer
Forming a MOS transistor separately,
Forming a pole, and forming a transparent support substrate on the element formation surface.
Bonding, and etching the back surface of the single-crystal Si substrate
Removing the transparent pixel electrode,
Removing or falling edge of quenching the stopper layer and the single crystal Si portion parts
And a process for producing a liquid crystal display array. 6. A liquid crystal display array according to claim 4 or 5.
In the manufacturing method, the single crystal Si substrate has an etching speed higher than that of Si inside the single crystal Si substrate.
The process of forming an etching stopper layer having a small degree
A method for manufacturing a liquid crystal display array, wherein the method is performed by ion implantation of B, O, and N. 7. A step of forming a groove in a single-crystal Si substrate,
Etching with a lower etching rate than Si in the groove
Forming a stopper layer and a single crystal S other than the groove.
forming a MOS transistor in the i-portion;
Forming a transparent pixel electrode on the element forming surface;
A step of bonding a bright support substrate, and a back surface of the single crystal Si substrate.
Removing the liquid crystal to the etching stopper layer . 8. A MOS transistor is formed on a single crystal Si substrate.
Forming a transparent pixel electrode;
Work to make the i-substrate thinner from the back and join the transparent support plate
And removing the single crystal Si substrate of the transparent pixel electrode portion
Forming a cavity, and filling the cavity with a transparent sealant.
Method of manufacturing a liquid crystal display array comprising a that step. 9. A MOS transistor on a single crystal Si substrate
Forming a transparent pixel electrode;
A transparent conductor that becomes the counter electrode by thinning the i-substrate from the back
Bonding a transparent support substrate with
Step of forming a cavity by removing a single-crystal Si portion at an extreme portion
And injecting a liquid crystal into the cavity . 10. A liquid crystal display array according to claim 8 or 9.
In the method of (a), an edge is provided between the transparent pixel electrode and the single crystal Si substrate.
A method for manufacturing a liquid crystal display array, comprising a step of forming a sacrificial layer for guiding a chilling liquid . 11. A method for manufacturing the liquid crystal display array according to claim 10.
In the method, the MOS transistor is formed using a single crystal Si substrate.
Wherein the transparent pixel electrode is a single crystal of a transparent pixel electrode portion.
Liquid crystal is injected from the removed part of the part,
The gap between the crystal Si substrate and the opposite substrate that defines the liquid crystal cell thickness
A method of manufacturing a liquid crystal display array, wherein the liquid crystal display array is a spacer or a pixel separation wall .