JP2001356710A - Active matrix layer and transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively protect a pixel electrode 30 from stress even through an inorganic buffer layer is used as a substrate for forming a thin film active element 90. SOLUTION: An active matrix layer to be transferred includes the TFT thin film active element 90 or the like in addition to an ITO pixel electrode 30. Firstly, such the active matrix layer is inserted in sandwich-like form on a heat-resistant substrate 10 by a peeled layer 20 being a peeled portion at the time of transfer and a protective film 40 for protecting from occurrence of a crack. Secondly, a buffer layer 500 to support an electrode 94 of the thin film active element 90 is thinly formed in the shape of a solid image to such an extent that does not impair a function of the buffer layer. The thickness is 10-20 nm, for example.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for forming an active matrix layer on one surface of a sheet substrate made of a plastic material by transfer. The active matrix layer to be transferred is more excellent in heat resistance than a plastic material. Transfer technology formed on the substrate side.

[0002]

BACKGROUND OF THE INVENTION Active-matrix driven liquid crystal panels including thin-film active elements such as TFTs and MIMs
Compared with the passive matrix drive that does not include such an active element, the display performance such as contrast is superior. In order to form an active matrix layer including a thin-film active element in addition to a matrix-shaped pixel electrode, a high-temperature treatment of 200 ° C. or more is required in the manufacturing process, and extremely accurate alignment is required. Usually, glass is used as the substrate of the liquid crystal panel, and in that case, the above-mentioned points were not a problem. However, the demand for thinner and lighter portable display terminals has increased, and when a sheet made of a plastic material is used as the substrate, unlike glass, plastic is inferior in heat resistance and dimensional stability. Is very difficult to form directly. Therefore,
It is conceivable to transfer an active matrix layer formed in advance on a substrate having excellent heat resistance, such as glass, onto a plastic sheet substrate. This type of transfer technique is already known as one of techniques for forming an active matrix layer for an optical display device such as a liquid crystal panel. This transfer technique basically forms an active matrix layer on a temporary substrate that temporarily supports the active matrix layer via a release layer, and then connects the active matrix layer via an adhesive layer. Transfer to another sheet substrate. The basics are described in, for example, Japanese Patent Application Laid-Open No. 8-62591. In addition, about the adhesive used as an adhesive layer, generally,
Formed on the active matrix layer of the temporary substrate,
In some cases, it can be formed on the side of another sheet substrate.

However, the technique disclosed in Japanese Patent Application Laid-Open No. H8-62591 requires a complicated process such as using metal plating for a release layer and providing a transparent electrical insulating layer between the release matrix and the active matrix layer. In addition, since a solvent-type pressure-sensitive adhesive is used as the adhesive, a stress problem occurs. When an adhesive containing a solvent is used, there is no place for the solvent to escape, and shrinkage during curing becomes extremely large. This causes stress, which easily causes disconnection or the like in the active matrix element. Even when other types of adhesives are used, the adhesive always changes in volume upon curing. Therefore, in the technique of transferring using an adhesive, a measure against a volume change is indispensable.

The inventors of the present invention have conducted various experiments and studies on a technique for forming an active matrix layer by such transfer. When transferring the active matrix layer from a temporary substrate side to another sheet substrate side, the inventors have found that the technique has been studied. We paid attention to the possibility that cracks may occur in the active matrix layer. When the cause was investigated, it was found that the active matrix layer was thin and relatively brittle, and was unable to withstand the external force applied during transfer. The main cause of the external force is the stress accompanying the curing shrinkage of the adhesive for bonding the active matrix layer to the side of the sheet substrate, which acts on the active matrix layer when the temporary substrate is peeled off during transfer. . Also, if such stress remains after transfer,
Cracks are likely to occur when stresses such as high temperature and high humidity are applied. The concept of protecting the active matrix layer against the stress applied from the side of the adhesive has not been considered up to now, including the aforementioned publication. And especially, the problem caused by such stress is that ceramics, glass,
Metals (preferably metal materials having low thermal expansion such as 42 alloys and copper alloys) or those having a greater rigidity than a sheet substrate made of a plastic material, such as a composite material obtained by laminating and combining a plurality of them. Notable when used. Further, assuming that a temporary substrate is formed on a pattern, dimensional stability against temperature and humidity is important, and a plastic material is not a desirable material.

When an active matrix layer is formed on a temporary substrate via a release layer, it is necessary to form a buffer layer on at least a release layer in a region where a thin film active element is to be formed. This buffer layer improves the adhesiveness of the electrodes of the thin-film active element, and also prevents the outgassing from the release layer during the formation of the electrode at a high temperature, thereby preventing the element characteristics from deteriorating. As the buffer layer, an inorganic layer such as SiOx or SiNx is preferable. However, when transferring the active matrix layer, these inorganic layers may cause cracks in the active matrix layer (especially, a pixel electrode having a larger area) or may cause poor transfer (for example, if the release layer or the active matrix layer is temporarily (A problem of remaining on the substrate).

[0006]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a technique for effectively protecting an active matrix layer from external force during transfer. Another object of the present invention is to provide a technique capable of effectively protecting a thin film active element and a pixel electrode from stress despite using an inorganic buffer layer as a base for forming a thin film active element. The purpose of. Further, a third object of the present invention is to provide a technique capable of effectively controlling the thickness of an adhesive layer which is a main cause of external force. Still another object of the present invention is to prevent a transfer failure when a layered material is transferred from a rigid heat-resistant temporary substrate to a sheet substrate made of a plastic material.

[0007]

According to the present invention, when an active matrix layer formed in advance on a substrate having excellent heat resistance is transferred to a sheet substrate made of a plastic material, an active matrix layer to be transferred is formed. On a heat-resistant substrate, a release layer which becomes a release portion at the time of transfer and a protective film for protecting the above-mentioned cracks from being generated are sandwiched between them. Since the active matrix layer is protected by the release layer and the protective film during the transfer, in particular, the protective film on the side of the adhesive layer acts to absorb or buffer the external force described above, thereby effectively preventing the occurrence of cracks. Can be prevented.

As one of the release layers sandwiching the active matrix layer in a sandwich shape, heat resistance enough to form the active matrix layer, firm adhesion to the active matrix layer, and patterning when forming the active matrix layer are used. Resistance to the etching process, etc., and moderate adhesion to the temporary substrate (adhering firmly to the temporary substrate before peeling, and peeling without damaging other layers) For example, several g to 1 at 90 ° peeling.
It is necessary to have an adhesiveness that requires a peeling force of about 00 g / cm). Materials suitable for the release layer are polyimide, acrylic, and epoxy. For example, polyimide has different adhesion to glass depending on the type. The first one synthesized from pyromellitic anhydride and 4,4'-diaminodiphenyl ether has S on the surface.
Adhesion with glass coated with iO ₂ is not so good, and it is suitable as a material for a release layer. In contrast, the second polyimide synthesized from benzophenonetetracarboxylic anhydride or pyromellitic anhydride and 3,3′-diaminodiphenylsulfone has better adhesion to glass than the first polyimide. In addition, the adhesion between the polyimide and the glass is improved by baking, and gradually decreases over time, and does not change at a certain point.
However, when baking is performed again on the material having such reduced adhesion, the adhesion is restored. The first polyimide can be peeled off from the glass immediately after baking, but after a few days, the adhesiveness is so reduced that it can be peeled off by washing with water (90).
° Peeling less than 1 g / cm). On the other hand, the second polyimide cannot be peeled off from the glass immediately after baking, but can be peeled off after a lapse of time.
It is considered that such a change in the adhesion of polyimide is caused by moisture absorption of polyimide. Therefore, the polyimide can be used as the release layer while considering such characteristics of the polyimide. Further, for example, by adding a silane coupling agent to the first polyimide having poor adhesion, the adhesion to glass can be optimized.

In consideration of the fact that the active matrix layer as the object to be transferred is peeled off from the release layer portion, it is better that the adhesion is small. However, as described above, the cleaning accompanying the step of forming the pattern of the active matrix layer is performed. At least a certain degree of adhesion is required to withstand manufacturing processes such as etching and etching. Further, in order to peel the active matrix layer by lifting the active matrix layer by placing it on the release layer so as not to apply excessive stress to the active matrix layer, the strength of the release layer is 100 g / cm in tensile strength.
The strength should be not less than (per 1 cm width), preferably not less than 150 g / cm. In order to increase the tensile strength of the release layer, it is possible to increase the thickness of the release layer. As a function required for the release layer, the temperature at the time of forming the active matrix layer and the resistance to a chemical used for patterning and forming the layer are also required. Moreover, it goes without saying that the release layer must have good adhesion to the buffer layer. As described above, polyimide is most suitable as the material of the release layer. By forming this on a heat-resistant glass substrate to have a thickness of 1.3 μm or more, preferably 2 μm or more, a necessary tensile strength can be obtained.

[0010] Depending on the material and thickness of the release layer, when a layered material is transferred from a rigid temporary substrate onto a sheet substrate made of a plastic material and peeled off, the release layer and the active matrix layer are partially transferred. In some cases, a phenomenon (transfer failure) of remaining on a temporary substrate may occur. At this time, it was observed that the active matrix layer, which has much higher adhesiveness than the temporary substrate and the release layer, was peeled off from the protective film in the middle of the layer or from the interface between the protective film and the adhesive layer. Also, even if the active matrix layer is transferred to the sheet substrate, subsequent heat treatment,
Alternatively, when a stress such as a high temperature and high humidity test is applied, wrinkles are generated in a direction perpendicular to the peeling direction. This is because
This is considered to be due to the fact that the active matrix layer, which is harder than the sheet substrate made of a plastic material at the time of peeling, resists the force against bending at the time of peeling.

In the present invention, when a sheet substrate made of a plastic material having an active matrix layer formed thereon is transferred and peeled from a rigid temporary substrate, the sheet substrate can be peeled off from an interface between the temporary substrate and the release layer. In addition, as a result of various studies on methods for preventing cracks generated in the active matrix layer, it has been clarified through experiments that it is sufficient to increase the film strength of the release layer. In order to transfer at least the release layer and the adhesive layer from the rigid temporary substrate to the sheet substrate composed of a highly flexible plastic material, the sheet substrate composed of the plastic material is peeled off from the rigid temporary substrate. At this time, the structure from the release layer to the sheet substrate made of a plastic material is integrated. Therefore, it seems that the release layer easily peels off from the interface between the temporary substrate and the release layer. However, in order to perform effective release, as described above, the material and thickness of the release layer are controlled to reduce the strength of the release layer. It is necessary to increase the strength as described above. Under such conditions, while ensuring at least the adhesion (adhesion) between the release layer and the adhesive layer,
Peeling can be performed by lifting on a peeling layer. As described above, by using the release layer having a certain tensile strength, the active matrix layer and the like can be effectively transferred regardless of the material of the active matrix layer and the intermediate protective film. The transfer can be performed without applying excessive stress to the matrix layer. As a result, after transfer, heat treatment,
Alternatively, even when a stress such as a high-temperature and high-humidity test is applied, wrinkles do not occur in the active matrix layer, and the heat resistance and high-temperature and high-humidity resistance of the transferred active matrix layer can be improved. At this time, if there is a nearly solid film in the active matrix layer, a stronger film strength is required for the release layer.

On the other hand, the other protective film sandwiching the active matrix layer in a sandwich shape is a film for protecting the active matrix layer together with the release layer, and includes, for example, alkyd (for example, EXP-1474 Fujikura Kasei), An organic film such as acrylic (for example, SS6917 Japan Synthetic Rubber). While the thickness of the release layer is 2 to 8 μm, the thickness of the protective film is 1.5 to 5 μm, and from the viewpoint of protection properties, the Young's modulus is 500 to 2000 kg / m.
m ² , the pencil hardness (JIS K5401) is H
The above is preferably set to 2H or more. In the case of a soft protective film, the stress generated from the active matrix layer after transfer cannot be supported, and the active matrix layer is easily deformed and cracked. On the other hand, if it is too hard, cracks are likely to occur in the protective film itself.

The active matrix layer includes a large number of pixel portions arranged in a matrix and a bus line running around the periphery of each pixel portion and supplying a signal to each pixel portion. , A pixel electrode formed corresponding to each pixel portion, and a thin-film active element connected to each pixel electrode. As a thin film active element, TF
In addition to the three-terminal element of T, there are two-terminal elements such as MIM and diode. In the case of a three-terminal element, the bus line is composed of a vertical bus line and a horizontal bus line which cross one surface of the substrate in the vertical and horizontal directions. On the other hand, in the case of a two-terminal element, when a common electrode is formed on the counter substrate side of the panel, the vertical bus lines and the horizontal bus lines are formed in accordance with the three-terminal element. Is not a common electrode but an independent electrode group corresponding to each pixel unit,
One of the vertical bus lines or the horizontal bus lines is used as a bus line in the active matrix layer, and the other of the vertical bus lines or the horizontal bus lines is used as a bus line for an electrode on the counter substrate side.

According to the present invention, the buffer layer for supporting the electrode of the thin film active element is formed in a thin solid shape as long as the function of the buffer layer is not impaired.
The use of an inorganic buffer layer to effectively form a thin-film active element and the effective protection of the pixel electrode from stress despite the presence of the inorganic buffer layer are both compatible, and also a temporary substrate. From the sheet to the sheet substrate. The thin solid buffer layer has a thickness of several tens of nm, preferably 10 to 20 nm, not only in the region occupied by the thin film active element but also in the region of the pixel electrode. This thickness is made as thin as possible in consideration of the function of improving the adhesion of the electrodes of the thin-film active element and preventing the deterioration of characteristics due to outgas from the release layer during the manufacturing process. This prevents the occurrence of cracks in the pixel electrodes and the like due to bending stress during transfer. In this regard, in order to reliably exhibit the original function of the buffer layer, its thickness is set to be thick, for example, 100 to 200 nm, and the buffer layer is patterned as a means for releasing stress applied to the thick buffer layer. By doing so, it is possible to disperse the stress from the cut portion. Compared with such a technique, the solid thin buffer layer of the present invention does not require a patterning step for making a cut, and is advantageous in process.

As the temporary substrate having heat resistance, a single substrate of ceramics, glass, and metal or a substrate in which they are combined can be widely used, but a glass substrate is particularly preferable. This is because glass not only has excellent heat resistance, but also can be formed while accurately positioning an active matrix layer, a color filter layer, and the like thereon. As described above, glass is a preferable material in relation to polyimide, which is a material of the release layer.

Next, as a material of an adhesive layer for adhering the active matrix layer to the plastic sheet substrate side, an ultraviolet curable adhesive which cures without applying heat is preferable. Among them, a cationic polymerization type, for example, an epoxy ultraviolet curing adhesive is most suitable. The thickness of the coating is about 2 to 20 μm, and the thickness is set to a value that can provide a sufficient adhesive strength and does not lose the transmittance. In the adhesive layer formed by such an adhesive, a difference occurs in the film thickness distribution depending on the pressing conditions at the time of lamination, or the adhesive protrudes from the side. Therefore, it is preferable to provide a spacer means for controlling the thickness of the adhesive layer at the portion of the adhesive layer. As the spacer means, spacer particles mixed in the adhesive layer or a spacer pattern formed on the protective film can be used. The spacer means is particularly effective for forming a uniform adhesive layer on a layer including a thin film active element and a color filter layer on one surface of a substrate having a relatively large area.

The sheet substrate made of a plastic material can be used in any form of a sheet (sheet) or a roll, and the preferred thickness is in the range of 100 to 700 μm. Therefore, the sheet substrate referred to here is a concept that includes a sheet-like member including a so-called film or sheet. As a plastic material, polyether sulfone, polyester, polycarbonate, vinyl chloride, nylon, polyarylate, acryl, polyimide, or the like can be used.

[0018]

FIG. 1 is a view of an active matrix layer according to an embodiment of the present invention as viewed from above a substrate.
FIG. 2 is an enlarged sectional view of a portion along line 2-2 in FIG. 1. When the temporary glass substrate 10 before transfer (the sheet substrate 80 made of a plastic material after transfer) is viewed from above, a horizontal bus line 71 as a metal wiring and a vertical bus line 72 as a gate wiring cross each other, A large number of pixel portions in a matrix are partitioned. Each pixel portion includes a pixel electrode 30 made of ITO occupying most of the pixel portion, and a thin-film active element 90 located at one corner of each pixel electrode 30 and connected to the pixel electrode 30. The thin film active element 90 is a TFT, and includes a gate electrode 94 and a drain electrode 9.
5 and a source electrode 99. In this embodiment, as the buffer layer 500 on the polyimide layer 20 as a release layer, not only the region occupied by the TFT 90 as a thin film active element but also the pixel electrode 3 before the formation of the pixel electrode 30.
It is formed in a solid shape over the region of 0 and further over each of the bus lines 71 and 72. Usually, as the buffer layer,
When the buffer layer 500 is formed to have a thickness of several hundred nm, the thickness of the buffer layer 500 is several tens nm (for example, 10 to 20 nm).
It is. That is, the thickness of the buffer layer 500 is reduced within a range that does not significantly reduce the function of improving the adhesion of the gate electrode 94 of the TFT 90 and preventing the characteristic deterioration due to outgas from the release layer 20 during the manufacturing process. ing.
Thereby, the pixel electrode 3 is bent by the bending stress at the time of transfer.
Cracks are prevented from occurring at 0 or the like.

Pixel electrode 30 and thin film active element 9
Active matrix layer containing 0 is a temporary glass substrate 1
When forming on the glass substrate 0, first, a washed glass substrate 10 is prepared, and a transparent polyimide layer 20 as a release layer is formed on one surface thereof by coating. The thickness of the glass substrate 10 is about 0.7 to 1.1 mm, and has rigidity as a whole. Since the glass substrate 10 is a substrate that supports the pixel electrode 30 to be transferred onto the surface thereof, it has good surface smoothness, for example, scratches and protrusions when visually observed with reflected light having a brightness of 5000 Lux in a dark room. It is desirable to have surface smoothness (appearance standard of the substrate surface) to such an extent that the surface cannot be seen. The polyimide layer 20 is obtained by adding a silane coupling agent having a solid content of 0.1% to the first polyimide, and has a thickness of 2 to 8 μm.
It is. Of course, the polyimide layer 20 is cured by a heat treatment after being applied. Glass substrate 10
Can of course sufficiently withstand heat treatment for curing the polyimide.

Next, an active matrix layer is formed on the polyimide layer 20 of the glass substrate 10.
In forming the active matrix layer, first, an ITO film is formed on the release layer 20, and then a pixel electrode 30 having a predetermined shape is obtained by patterning. Plasma CV is applied over the entire surface
A SiOx film is formed as a buffer layer 500 with a thickness of 10 to 20 nm by D, and a gate metal is formed on the buffer layer 500 and patterned to form a gate electrode 94 and a gate wiring 72. As a material for the gate electrode wiring,
Normally, TaN, Mo / Ta, Cr, Mo / W, etc. are used, but Al is optimal for an active element to be transferred onto plastic. This is because the force generated during transfer and the product after transfer is on plastic, the coefficient of thermal expansion of the base material is large, a large force is applied to this part, and excessively hard metal materials will crack and break. This is because it easily occurs. After that, plasma CVD or EC
A 300 nm thick gate insulating film 910 of a SiNx film, a SiOx film or a laminated film thereof is formed by R-CVD, and a channel layer 9 of a-Si (amorphous silicon) is continuously formed.
2 is formed to a thickness of 100 nm. At this time, the film formation temperature is set to the release layer 2
The heat treatment is performed at a temperature of 200 ° C. to 300 ° C. Further, a channel stopper layer 93 of a SiNx film is continuously formed to a thickness of 400 nm. Next, the channel stopper layer 9
After patterning No. 3, n + a-
A 400-nm thick doped a-Si 97 for contact with Si is formed. Then, the doped a-Si 97 for contact and the a-Si 92 for channel are patterned, and further, the gate insulating film 910 is patterned. Finally, a metal wiring 71 is formed and patterned. The material of the metal wiring 71 is also preferably aluminum for the above-described reason. At this time, aluminum is used as the ITO of the pixel electrode 30.
If it is formed so as to be in direct contact with aluminum, the work function of aluminum is smaller than that of ITO, which may cause a problem. Therefore, between the ITO and the aluminum wiring, 2
A thin chrome barrier electrode of 100-300 Å is formed. After that, the pixel electrode 3 on the glass substrate 10
Acrylic protective film 40 is formed to a thickness of 1.5 to 5 μm so as to cover 0 and TFT 90.

Thereafter, a color filter layer 50 including yellow, magenta, and cyan color pixel patterns is formed on the protective film 40 by photolithography. As a material for the color pixel pattern, a known coating material in which a coloring agent such as a dye or a pigment is dissolved or dispersed in a polyimide resin solution can be used (for example, see Japanese Patent Application Laid-Open No.
-170716). Each color pixel pattern has a dot shape, a width of 50 to 200 μm, and a distance between adjacent color patterns of 5 to 20 μm. The thickness of the color filter layer 50 is 0.2 to 2 μm. At this time, since each color pixel pattern of the color filter layer 50 and the active matrix layer including the pixel electrode 30 and the TFT 90 are aligned on the glass substrate 10 having excellent dimensional stability, patterning and alignment are performed. No problems occur above.

Further, an adhesive layer 60 is formed by coating so as to entirely cover the color filter layer 50.
The adhesive forming the adhesive layer 60 is an ultraviolet-curable adhesive, and is a cationic polymerization type epoxy-based ultraviolet-curable adhesive (UV curable resin KR400 manufactured by Asahi Denka Kogyo Co., Ltd.).
Is used. The thickness of the coating is about 2 to 20 μm, and the thickness is set to a value that can provide a sufficient adhesive strength and does not lose the transmittance. At this time, spacer particles such as 4 μm benzoguanamine spherical particles (not shown) are mixed into the adhesive layer 60 as spacer means. Spacer particles are added in advance to the material to be applied,
The application to the substrate 10 is performed. At this time, the adhesive is in a liquid state, and it is desirable to control the thickness of the coating film slightly larger than the size of the spacer particles. When the glass substrate 10 and the sheet substrate 80 as a plastic sheet are laminated in this state, the adhesive layer 60 having a uniform film thickness over the entire surface can be obtained. In addition, as for the mixing amount of the spacer particles, after forming the adhesive layer 60, the in-plane distribution amount is 40 particles / mm ^2.
It is preferable to adjust the temperature to the degree. Here, the epoxy resin of the adhesive layer 60 undergoes volume shrinkage of, for example, about several percent due to photocuring, but the spacer particles are unlikely to undergo such a change. Therefore, undesired deformation or stress is generated in the spacer particles due to the volume shrinkage of the adhesive layer 60, and a crack may be generated in the pixel electrode 30 or the like. In order to avoid this, the particle diameter of the spacer particles should be smaller than a predetermined value, for example, preferably set to 5.5 μm or less. As the spacer means, in addition to the spacer particles, a spacer pattern patterned in an island shape or a stripe shape between each color pixel pattern of the color filter layer 50 (this portion is also a portion having no pattern of the pixel electrode 30) is used. You can also. The spacer pattern does not damage the pixel electrode 30 due to undesired deformation or stress. Further, the spacer pattern can be formed using a polyimide resin mixed with a black coloring material. Then, there is an advantage that the display contrast is further improved when performing liquid crystal display.

Thereafter, a sheet substrate 80 made of a polyethersulfone material (having a thickness of 100 to
700 μm), the pixel electrode 30 and the TFT 9
0 and the color filter layer 50 etc.
The image is transferred from the 0 side to the sheet substrate 80 side. In this transfer process, ultraviolet rays are irradiated from the sheet substrate 80 side,
At the same time, the temperature rise on the side of the adhesive layer 60 (curing target) due to the irradiation is positively suppressed, and the temperature is set as close to room temperature as possible. During this transfer, the pixel electrode 3 that is particularly susceptible to damage
Since 0 is sandwiched between the polyimide film 20 as a peeling layer and the protective film 40, it is effectively protected from external force accompanying the curing and transfer of the adhesive layer 60. As a comparative example, when the same material system was used without the protective film 40 as described above, the active matrix layer after the transfer was caused by the internal stress caused by the shrinkage of the spacer particles, the spacer pattern, and the adhesive upon curing. Cracks were occurring in some places. At the time of transfer, a roll was used for peeling, and the roll was peeled along the circumference of the roll. By setting the diameter of the roll used to 50 mm or more, preferably 100 mm or more, it is possible to prevent an excessive bending force from being applied to the active matrix layer.

After the transfer, the polyimide layer 20 as a release layer
Is removed. This is to enable electrical connection between the active matrix layer including the pixel electrode 30 and the TFT 90 and the driver IC for liquid crystal display, and also to improve the effective voltage for driving the liquid crystal. Regarding the removal of the polyimide layer 20, hydrazine-
Wet etching using ethylenediamine or plasma dry etching is used.

Although the solid buffer layer 500 is formed before the pixel electrode 30 in the above-described embodiment, first, the pixel electrode 30 made of ITO is patterned, and then the solid thin buffer layer 500 is formed. A layer may be formed, and the gate electrode 94 of the TFT 90 may be formed on the buffer layer. Further, thinner buffer layers can be formed above and below the pixel electrode, and the upper and lower buffer layers can block outgas from the peeling layer 20 when the TFT 90 is formed. The thinner buffer layer in the lower layer is advantageous in improving the adhesion of the pixel electrode 30 to ITO, and the disadvantage in function of the buffer layer due to the thinner buffer layer is reduced in the upper buffer layer. Can be covered.

Comparative Example 1 A release layer having a thickness of 1 μm was formed on a glass substrate using the same material as in the above-described example. The tensile strength of this release layer is 7
It was 5 g / cm. Thereafter, each layer was formed under the same conditions as in the example. This was transferred to a sheet substrate under the same conditions as in the example, and peeled off from the roll under the same conditions as in the example, but a portion of the active matrix layer almost remained on the temporary substrate side, and the protective film and the color filter layer It was peeled off from the interface or the interface between the color filter layer and the adhesive layer. In addition, regarding the interface between the protective film and the color filter layer or the interface between the color filter layer and the adhesive layer, when a film is formed on a glass substrate alone and the adhesion is evaluated, a cross-cut cellotape (registered trademark) test (JIS 5400-8 .5.
It did not peel off in 1).

Comparative Example 2 Each layer was formed under the same conditions as in the example except that the metal wiring of the active matrix was formed of chromium. This was transferred to a sheet substrate under the same conditions as in the example, and peeled off from the roll under the same conditions as the example. As a result, the wiring of the active matrix layer was full of disconnections.

[Brief description of the drawings]

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

FIG. 2 is an enlarged sectional view of a portion along line 2-2 of FIG.

[Explanation of symbols]

 Reference Signs List 10 glass substrate 20 polyimide layer (peeling layer) 30 pixel electrode 40 protective film 50 color filter layer 60 adhesive layer 71, 72 bus line 80 sheet substrate 90 TFT (thin film active element) 500 buffer layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 29/786 H01L 29/78 612D 21/336 619A 626C 627D (72) Inventor Ichiro Betsumiya Koishikawa Bunkyo-ku, Tokyo 4-14-12 Kyodo Printing Co., Ltd. (72) Inventor Takashi Sato 4- 14-12 Koishikawa Bunkyo-ku, Tokyo Metropolitan Printing Co., Ltd. (72) Kazumi Arai 4-14 Koishikawa Bunkyo-ku, Tokyo No. 12 Inside Kyodo Printing Co., Ltd. (72) Inventor Fumiyoshi Matsumoto 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company Limited (72) Inventor Akihiko Kanemoto 1-3-6 Nakamagome, Ota-ku, Tokyo No. F-term in Ricoh Co., Ltd. (reference) 2H090 HA03 HA04 HB08X HB13X HC05 HD02 JA07 JA09 JB02 JB03 JC07 LA01 LA02 LA04 LA15 2H092 JA24 JB56 JB57 KB21 KB24 MA08 MA10 MA31 NA13 NA15 NA17 NA29 PA01 PA03 PA08 5C094 AA42 AA43 AA60 BA03 BA43 CA19 CA24 DA13 DB01 DB04 EA04 EA05 EB01 ED03 FA01 FA02 FB01 FB02 FB12 FB14 FB15 GB10 JA20 5F110 AA03 EE03 DD03 DD01 FF30 FF31 GG02 GG15 GG25 HK09 HK16 HK35 HL03 HM18 NN02 NN12 NN24 NN27 NN35 NN72 QQ09 5G435 AA00 AA17 BB12 CC09 CC12 GG12 HH12 HH13 HH14 HH18 KK05

Claims (12)

[Claims] 1. An active matrix layer supported as a result of transfer on one surface of a sheet substrate made of a plastic material via an adhesive layer, and the active matrix layer is composed of a plurality of active matrix layers arranged in a matrix on one surface of the substrate. And a bus line that runs around the periphery of each pixel unit and supplies a signal to each pixel unit.
An active matrix layer including a pixel electrode formed corresponding to each pixel portion, a thin film active element connected to each pixel electrode, and further having the following characteristic requirements. a. There is a buffer layer that supports the electrode of the thin-film active element, and the buffer layer has a thickness of several tens nm, not only in the area occupied by the thin-film active element, but also in the area of the pixel electrode. . b. Of the upper and lower surfaces of the pixel electrode and the buffer layer,
One surface is the side that comes into contact with the release layer for the transfer. c. An organic protective film covers the other surface of the pixel electrode and the thin-film active element on the other surface of the buffer layer. 2. The buffer layer has a solid shape including the pixel portion and a bus line around the pixel portion.
2. The active matrix layer according to claim 1, which is from 0 to 20 nm. 3. The active matrix layer according to claim 1, wherein the buffer layer is an inorganic layer serving as a base for effectively forming the thin film active element including an electrode. 4. An active matrix layer including a matrix-shaped pixel electrode separated from each other and a thin-film active element connected to each pixel electrode is formed on one surface of a sheet substrate made of a plastic material. A matrix layer is formed on the substrate side that has excellent heat resistance compared to the plastic material, and thereafter,
A method of transferring the active matrix layer to the sheet substrate side via an adhesive layer, wherein the active matrix layer on the substrate having excellent heat resistance is peeled off at the time of transfer in order to protect against stress during the transfer. The release layer to be a part and the organic protective film covering the active matrix layer are sandwiched, and the inorganic buffer layer serving as a base for effectively forming the thin film active element is formed by the thin film. Improving the adhesiveness of the electrodes of the active element and forming it as thin as possible without impairing the function of preventing the characteristic deterioration caused by outgas from the release layer during the manufacturing process of the thin film active element.
Active matrix layer transfer method. 5. The buffer layer has a thickness of 10 to 20 nm.
The transfer method according to claim 4, wherein 6. The substrate having excellent heat resistance is a substrate made of a single substance of ceramics, glass, and metal, or a substrate in which they are combined, and the release layer is made of a polyimide-based, acrylic-based, or epoxy-based resin. The transfer method according to claim 4. 7. The transfer method according to claim 4, further comprising an adhesive layer made of an adhesive on the substrate having excellent heat resistance and on the protective film. 8. The transfer method according to claim 7, further comprising a spacer means for controlling a thickness of the adhesive layer at a portion of the adhesive layer. 9. The spacer means is a spacer particle mixed in the adhesive layer or a spacer pattern formed on the organic protective film.
Transfer method. 10. The transfer method according to claim 4, wherein aluminum is used for a metal wiring forming a bus line of the active matrix layer. 11. The active matrix layer is for a liquid crystal color display device, wherein a color filter layer for color display is formed on the organic protective film, and the adhesive layer forms the color filter layer. Wearing,
The transfer method according to claim 4. 12. The release layer has a tensile strength of 100 g.
The transfer method according to claim 4, wherein the transfer method is not less than / cm.