CN1904707B - Transmission type liquid crystal display device and method for fabricating the same - Google Patents

Abstract

The transmission type liquid crystal display device of this invention includes: gate lines; source lines; and switching elements each arranged near a crossing of each gate line and each source line, a gate electrode of each switching element being connected to the gate line, a source electrode of the switching element being connected to the source line, and a drain electrode of the switching element being connected to a pixel electrode for applying a voltage to a liquid crystal layer, wherein an interlayer insulating film formed of an organic film with high transparency is provided above the switching element, the gate line, and the source line, and wherein the pixel electrode formed of a transparent conductive film is provided on the interlayer insulating film.

Description

Transmission-type liquid crystal display device and manufacture method thereof

The application is to be that August 12, application number in 1996 are 02159891.6 the applying date, and denomination of invention is divided an application for " transmission-type liquid crystal display device and manufacture method thereof ".

Technical field

The present invention relates to a kind of transmission-type liquid crystal display device, it comprises on-off element, as Weimer triode (hereinafter being called TFT), and as addressed elements, and as the display of computing machine, televisor and so on; The invention still further relates to a kind of method of making this transmission-type liquid crystal display device.

Background technology

Figure 16 is the circuit diagram that possesses the normal transmissive liquid crystal display device of active matrix substrate.

Referring to Figure 16, the active matrix substrate comprises a plurality of pixel electrodes 1 that are arranged in matrix, with the TFT2 as the on-off element that links to each other with each pixel electrode 1.The grid of TFT2 links to each other with grid lead 3, is used to provide scanning (door) signal, thereby signal can be input to grid, the driving of control TFT2.The source electrode of TFT2 links to each other with source lead 4, is used to provide image (data) signal, thereby when TFT is activated, can data-signal be input to corresponding pixel electrode 1 by TFT.Grid lead 3 and source lead 4 are walked in the place near pixel electrode 1, and are arranged in matrix, intersect mutually.The drain electrode of TFT2 links to each other respectively with storage capacitor 5 with pixel electrode 1.Another utmost point of storage capacitor 5 links to each other with concentric line 6.Storage capacitor 5 is used for keeping the voltage that applies on the liquid crystal layer.Storage capacitor is in parallel with liquid crystal capacitance, and liquid crystal capacitance comprises between pixel electrode on the active matrix substrate and the liquid crystal layer between the respective pixel electrode on another substrate.

Figure 17 is common TFT of liquid crystal display device active matrix substrate sectional view partly.

Referring to Figure 17, the grid 12 that links to each other with grid lead shown in Figure 16 3 is formed on the transparent insulation substrate 11.Gate insulation film 13 is coated on the grid 12.Semiconductor layer 14 is formed on the insulation course 13, thereby covers on the grid 12 by gate insulation film 13, and channel protective layer 15 is formed on the central authorities of semiconductor layer 14.N as source electrode 16a and drain electrode 16b ⁺-Si layer is coated on the end of channel protective layer 15 and the part of semiconductor layer 14, thereby they are spaced from each other in the upper end of channel protective layer 15.To cover on the source electrode 16a, as the metal level 17a of source lead shown in Figure 16 4 as n ⁺-Si layer.Metal level 17b covers on the drain electrode 16b, as another n ⁺-Si layer, thus will drain 16b and pixel electrode 1 link together.Insulating film of intermediate layer 18 covers on TFT2, grid lead 3 and the source lead 4.Nesa coating is formed on the dielectric film, to constitute pixel electrode 1.Nesa coating links to each other with metal level 17b, and metal level 17b links to each other with the drain electrode 16b of TFT2 by a contact hole 19, and contact hole 19 passes insulating film of intermediate layer 18.

Therefore since insulating film of intermediate layer 18 be formed on pixel electrode 1 and comprise grid lead and the buried layer of source lead 3 and 4 between, so, can 3 and 4 cover pixel electrode 1 with lead-in wire.For example, a kind of like this structure can be the content that discloses in the document of 58-172685 referring to Japanese publication publication number.Adopt this structure, aperture opening ratio improves, and because of the electric field conductively-closed that is produced by line 3 and 4, so make the possibility minimum that swing offset occurs.

Usually, middle layer insulation course 18 is by chemical vapor deposition (CVD), and the inorganic material of deposit such as silicon nitride (SiN) forms to the about 500nm of thickness.

Above-mentioned common liquid crystal indicator has shortcoming as described below.

When by CVD or sputter on the insulating film of intermediate layer 18 and to form by SiNx, SiO ₂, TaOx etc. make transparent insulating film the time, the surface configuration of buried film (being insulating film of intermediate layer 18) has directly been reflected on the surface of film.So, when on transparent insulating film, forming pixel electrode 1, if buried film has step, then on pixel electrode, also can form step, thereby make the orientation of liquid crystal molecule disturbance occur.Another kind method is can form insulating film of intermediate layer 18 by the organic material that applies as polyimide, thereby obtain smooth pixel portion.Yet in this case, pixel electrode and drain electrode are electrically connected the contact hole of getting up, need take a series of step, comprise and adopt photoresist to form, form the etching of contact hole and the removal of photoresist as the photochemistry pattern of mask in order to form.Can adopt the light-sensitive polyimide film to shorten etching and removal step.Yet in this case, the insulating film of intermediate layer 18 of generation is colored.This is inappropriate for requiring high printing opacity and transparent liquid crystal display device.

Another shortcoming is as described below.When printing opacity insulating film of intermediate layer 18 covers pixel electrode 1 on grid lead 3 and the source lead 4, between pixel electrode 1 and the grid lead 3 and the capacitance between pixel electrode 1 and the source lead 4 increase.Particularly, when with the inorganic material of silicon nitride and so on during as insulating film of intermediate layer 18, the specific inductive capacity of this material will be up to 8, and because film is printing opacity CVD forms, 500nm is thick so the thickness of film will only be had an appointment.Adopt such insulating film of intermediate layer, the capacitance between pixel electrode 1 and line 3 and 4 is very big.This just produces following problem (1) and (2).Additional disclosure once, the thicker inoranic membrane in order to obtain being made by silicon nitride and so on material needs considerable time on the manufacturing process.

(1) when pixel electrode 1 covers on the source lead 4, it is big that the capacitance between pixel electrode 1 and the source lead 4 becomes.This has just improved the signal transmissivity, thereby the data-signal that keeps on retention time interior pixel electrode 1 will fluctuate with its electromotive force.As a result, the effective voltage that is applied on the pixel liquid crystal can change, and this can cause in the actual displayed the vertical interference to vertical neighbor especially.

In order to reduce the influence of electric capacity to showing between pixel electrode 1 and the source lead 4, advised a kind of driving method in the document that Japanese publication publication number is 6-230422, on each source lead, will offer the pole reversal of the data-signal of pixel.This driving method is that the white and black displays screen of height correlation is effective for the demonstration (being data-signal) of neighborhood pixels each other.Yet, colorful display screen for common notebook personal computer and so on has been not effectively just, and at this moment, pixel electrode is arranged in vertical bar shaped (in the color monitor, be divided into three kinds of vertical long rectangular image unit representing R, G and B as square pixel, form vertical bar shaped).

The Show Color of the pixel that links to each other with a source lead is different with the Show Color of the pixel that is connected with the adjacent source lead-in wire.Therefore, although suggestion is effectively with the driving method of the pole reversal of data-signal for black and white display to each source lead, when reducing the interference of common color display, be invalid.

(2) when pixel electrode 1 covers on the grid lead 3 that is used for driving pixel, it is big that the electric capacity between pixel electrode 1 and the grid lead 3 becomes, thereby the switching signal of control TFT2 can make the raising of presenting that writes voltage on the pixel.

Summary of the invention

Transmissive liquid crystal display device of the present invention comprises: grid lead, source lead, and the on-off element that is the near intersection shape respectively with each grid lead and each source lead.The gate electrode of each on-off element links to each other with grid lead, the source electrode of on-off element links to each other with source lead, the drain electrode of on-off element with voltage is applied to the pixel electrode that liquid crystal layer gets on and links to each other, wherein, be positioned on on-off element, grid lead and the source lead by organic film formed insulating film of intermediate layer with high-transmission rate.Has the film formed pixel electrode of electrically conducting transparent on the insulating film of intermediate layer.

In an embodiment of the present invention, this device also comprises a connection electrode, is used for connecting pixel electrode and drain electrode, and wherein, there is insulating film of intermediate layer the top of on-off element, grid lead, source lead and connection electrode.Pixel electrode is formed on the insulating film of intermediate layer, thus cover gate lead-in wire at least, and perhaps to small part cover gate lead-in wire, and connection electrode and pixel electrode interconnect by a contact hole that is formed by insulating film of intermediate layer.

In an embodiment of the present invention, insulating film of intermediate layer is made by photosensitive acrylic resin.

In an embodiment of the present invention, insulating film of intermediate layer is to be formed transparent resin and made by a kind of the processing by optics or chemical true qualities.

In an embodiment of the present invention, at least one lead-in wire in pixel electrode and source lead and the grid lead each other along the overlapping 1 μ m of wire widths direction or more than.

In an embodiment of the present invention, the thickness of insulating film of intermediate layer be 1.5 μ m or more than.

In an embodiment of the present invention, connection electrode is film formed by electrically conducting transparent.

In an embodiment of the present invention, device also comprises a storage capacitor, is used for keeping being applied to the voltage on the liquid crystal layer, and wherein, contact hole or be formed on the electrode top of storage capacitor perhaps is formed on the top of grid lead.

In an embodiment of the present invention, metal nitride layer is formed on the below of contact hole, in order to connect connection electrode and pixel electrode.

In an embodiment of the present invention, device also comprises a storage capacitor, is used for keeping being applied to the voltage on the liquid crystal layer, and wherein, the capacity ratio that capacity ratio is represented with equation (1) is less than or equal to 10:

Capacity ratio=C _Sd/ (C _Sd+ C _Ls+ C _s) ... (1)

C in the formula _SdCapacitance between remarked pixel electrode and the source lead, Cls are represented the capacitance of the lcd segment corresponding with each pixel in the middle show state, and Cs represents the capacitance of the storage capacitor of each pixel.

In an embodiment of the present invention, pixel electrode be shaped as rectangle, and one side parallel with grid lead is than a length of side parallel with source lead.

In an embodiment of the present invention, device also comprises one drive circuit, is used for providing data-signal to source lead, and the polarity of this data-signal is all reversed for horizontal scanning period, and data-signal offers pixel electrode by on-off element.

In an embodiment of the present invention, device also comprises a storage capacitor, be used for keeping being applied to the voltage on the liquid crystal layer, storage capacitor comprises: storage capacitor electrode, another electrode of storage capacitor and dielectric film therebetween, wherein, storage capacitor electrode or be formed in the source lead layer perhaps is formed in the connection electrode layer.

In an embodiment of the present invention, another electrode of storage capacitor forms a part of grid lead.

In an embodiment of the present invention, pixel electrode and storage capacitor electrode are to couple together by the contact hole that is formed on storage capacitor electrode top.

In an embodiment of the present invention, contact hole is formed in the top of another electrode of storage capacitor or the top of grid lead.

In an embodiment of the present invention, insulating film of intermediate layer is to be formed by the photosensitive resin that contains photoactive substance, and this photoactive substance (365nm) has a photoresponse peak value in ultraviolet i section (i ultraviolet ray).

Provided a kind of method of making transmission-type liquid crystal display device according to another aspect of the present invention.This method comprises the steps: to form a plurality of on-off elements with matrix form on a substrate; The grid lead that formation links to each other with the gate electrode of each on-off element, with the source lead that links to each other with the source electrode of this on-off element, grid lead and source lead are intersected mutually; Formation is by the film formed connection electrode of electrically conducting transparent that links to each other with the source electrode of on-off element.This method also comprises passes through painting method, above on-off element, grid lead, source lead and connecting line, form organic membrane with high grade of transparency, and organic membrane carried out pattern-forming, form insulating film of intermediate layer and contact hole, this contact hole passes insulating film of intermediate layer and arrives connection electrode.This method also comprises such step, promptly on insulating film of intermediate layer and the inboard of contact hole form the pixel electrode that forms by the electrically conducting transparent mould, thereby each pixel electrode at least cover gate go between or source lead perhaps its part at least.

In an embodiment of the present invention, the pattern of organic membrane form to adopt following any one step to carry out: make organic membrane exposure and the flushing organic membrane through exposure, perhaps adopt on the organic membrane this organic membrane of photoresist etching as etching mask.

In an embodiment of the present invention, the pattern of organic membrane forms and comprise the steps: to form the photoresist layer that contains silicon on organic membrane; On photoresist layer, form pattern; And adopt the figuratum photoresist of formation to come the etching organic membrane as etching mask.

In an embodiment of the present invention, the pattern of organic membrane forms and comprise the steps: to form photoresist layer on organic membrane; Silane coating bond on photoresist layer, and this bond of oxidation; On photoresist layer, form pattern; Employing is coated with the patterning photoresist layer of oxidation bond as etching mask, etching organic membrane.

In an embodiment of the present invention, etching step is to adopt to contain the step that at least a etching gas among CF4, CF3H and the SF6 carries out dry etch.

In an embodiment of the present invention, organic membrane forms with photosensitive transparent acrylic resin, this resin the time can be dissolved in the developing solution in exposure, and insulating film of intermediate layer and contact hole are by with photosensitive transparent acrylic resin exposure and develop and form.

In an embodiment of the present invention, this method also comprises the steps, promptly after the exposure and development of organic membrane, makes the entire substrate exposure, the photoactive substance that contains in the photosensitive transparent acrylic resin is reacted, thereby photosensitive transparent acrylic resin is discolored.

In an embodiment of the present invention, the raw polymer of photosensitive transparent acrylic resin comprises a kind of multipolymer with methacrylic acid and glycidyl methacrylate, and photosensitive transparent acrylic resin contains diazobenzene quinones positive photosensitive material.

In an embodiment of the present invention, the photosensitive transparent acrylic resin that forms insulating film of intermediate layer has 90% or higher light transmission to about 400nm to the light in about 800nm wavelength coverage.

In an embodiment of the present invention, organic membrane has about 1.5 μ m or above thickness.

In an embodiment of the present invention, this method also comprises such step, promptly before forming organic membrane, will form the substrate surface of organic membrane with UV-irradiation.

In an embodiment of the present invention, this method also comprises such step, promptly before forming organic membrane, applies the silane mixture on the substrate surface that will form organic membrane.

In an embodiment of the present invention, the material that is used for forming organic membrane contains the silane mixture.

In an embodiment of the present invention, the silane bond comprises at least a in hexamethyldisilazane, dimethyl diethoxy monosilane and the normal-butyl trimethoxy monosilane.

In an embodiment of the present invention, this method also comprises the steps, promptly before forming pixel electrode, makes the surperficial ashing (ashing) of insulating film of intermediate layer with oxygen gas plasma.

In an embodiment of the present invention, cineration step carries out after forming contact hole.

In an embodiment of the present invention, insulating film of intermediate layer comprises a thermal curable material, and insulating film of intermediate layer solidifies before cineration step.

In an embodiment of the present invention, the thickness of insulating film of intermediate layer ashing part arrives in the scope of 500nm about 100.

In an embodiment of the present invention, the thickness of pixel electrode be about 50nm or more than.

In an embodiment of the present invention, insulating film of intermediate layer is by the tetramethylammonium hydroxide water development liquid that is about 0.1mol% to 1.0mol% with concentration photosensitive clear acrylic to be developed to form.

In an embodiment of the present invention, this method also comprises the steps, is forming by after the contact hole of insulating film of intermediate layer, by with the UV-irradiation insulating film of intermediate layer insulating film of intermediate layer being discolored.

In an embodiment of the present invention, this method also comprises the steps, promptly before forming organic membrane, forms silicon nitride film at the substrate surface that will form organic membrane.

So, the invention has the advantages that (1) provides a kind of transmission-type liquid crystal display device, pixel electrode wherein covers each lead-in wire, thereby has improved the aperture opening ratio of LCD, makes the orientation disturbance minimum of liquid crystal molecule, and manufacturing process is simplified.In addition, can also reduce the influence of electric capacity to showing between pixel electrode and the lead-in wire, as crosstalk, thereby realize good demonstration.Another advantage of the present invention is that (2) provide a kind of method of making this transmission-type liquid crystal display device.

Description of drawings

Those skilled in the art will be more clear to above-mentioned and other advantage of the present invention after having read detailed description hereinafter in conjunction with the accompanying drawings.

Fig. 1 be according to a pixel portion of the active matrix substrate of the embodiment 1 of transmission-type liquid crystal display device of the present invention planimetric map.

Fig. 2 is the sectional view along A-A ' line among Fig. 1.

Fig. 3 is the planimetric map according to a pixel portion of the active matrix substrate of the embodiment 3 of transmission-type liquid crystal display device of the present invention.

Fig. 4 is the sectional view along B-B ' line among Fig. 3.

Fig. 5 is the part sectioned view according to the active matrix substrate of the embodiment 4 of transmission-type liquid crystal display device of the present invention.

Fig. 6 is the curve map that concerns between the liquid crystal charging rate variance of transmission-type liquid crystal display device of explanation embodiment 5,6 and traditional liquid crystal display device and the capacity ratio.

Fig. 7 A and 7B are respectively the waveforms of the data-signal under the situation that the 1H paraphase in embodiment 5 and 6 drives and traditional field paraphase drives.

Fig. 8 be explanation embodiment 5 transmission-type liquid crystal display device liquid crystal capacitance than and overlapping width between the curve map of relation.

Fig. 9 is the planimetric map according to a pixel portion of the active matrix substrate of the transmission-type liquid crystal display device of embodiments of the invention 7.

Figure 10 is the sectional view along C-C ' line among Fig. 9.

Figure 11 is the explanation curve map that changes with the transmitted light wavelength (nm) of the transmission-type liquid crystal display device of embodiment 7 of transmissivity before acryl resin exposure and afterwards.

Figure 12 is the circuit diagram of grid Cs type liquid crystal display device.

Figure 13 is the planimetric map of a pixel portion of active matrix substrate that the structure applications of Fig. 3 is obtained on liquid crystal display device shown in Figure 12.

Figure 14 is that the planimetric map Figure 15 according to a pixel portion of the active matrix substrate of the transmission-type liquid crystal display device of embodiments of the invention 10 is the sectional view along D-D ' line among Figure 14.

Figure 16 is the circuit diagram that is provided with traditional liquid crystal display device of active matrix substrate.

Figure 17 is the sectional view of a pixel portion of the active matrix substrate of traditional liquid crystal display device.

Embodiment

By example the present invention is described below with reference to accompanying drawings.

Embodiment 1

Fig. 1 is the planimetric map according to a pixel portion of the active matrix substrate of the transmission-type liquid crystal display device of embodiments of the invention 1.

Referring to Fig. 1, the active matrix substrate comprises a plurality of with matrix form pixel electrodes arranged 21.The grid lead 22 of scanning (door) signal is provided and provides the source lead 23 of image (data) signal around pixel electrode 21, to walk, and intersect each other.Each pixel electrode 21 periphery overlaps on grid lead 22 and the source lead 23.The TFT24 that plays on the corresponding pixel electrode 21 of being connected to of on-off element effect is formed on the point of crossing of grid lead 22 and source lead 23.The grid of TFT24 is connected on the grid lead 22, gate signal can be input on the grid, with controlling and driving TFT24.The source electrode of TFT24 is connected on the source lead 23, and data-signal can be input on the source electrode.The drain electrode of TFT24 is connected on the pixel electrode 21 by connection electrode 25 and contact hole 26.Drain electrode also is connected on the energy-storage capacitor electrode (energy-storage capacitor electrode 25a) by connection electrode 25.Another electrode of energy-storage capacitor (energy-storage capacitor consequent pole 27) is connected on the concentric line (element 6 among Figure 16).

Fig. 2 is the sectional view along the active matrix substrate of A-A ' line of Fig. 1.

Referring to Fig. 2, the grid that is connected to grid lead 22 32 shown in Fig. 1 is formed on the transparent insulation substrate 31.Gate insulating film 33 forms cover gate 32.Semiconductor layer 34 is formed on the gate insulating film 33, overlaps on the grid 32 by gate insulating film 33, and channel protective layer 35 is formed on the center of semiconductor layer 34.N as source electrode 36a and drain electrode 36b ⁺Silicon layer forms the part that covers channel protective layer 35 ends and semiconductor layer 34, so that they are separated from each other by channel protective layer 35 parts.The nesa coating 37a that becomes double-deck source lead 23 shown in Figure 1 and metal level 37b be made into overlap as a n ⁺On the source electrode 36a of silicon layer.Nesa coating 37a ' and metal level 37b ' be made into overlap as another n ⁺On the drain electrode 36b of silicon layer.Nesa coating 37a ' extension, to connect drain electrode 36b and pixel electrode 21, it also plays the effect of connection electrode 25, is connected on the energy-storage capacitor electrode 25a of energy-storage capacitor.Insulating film of intermediate layer 38 forms and covers TFT24, grid lead 22, source lead 23 and connection electrode 25.

Nesa coating is formed on and constitutes pixel electrode 21 on the insulating film of intermediate layer 38.Pixel electrode 21 is connected to by contact hole 26 on the drain electrode 36b of TFT24, and contact hole 26 runs through insulating film of intermediate layer 38 and as the nesa coating 37a of connection electrode 25.

Following manufacturing has the active matrix substrate of above-mentioned structure.

At first on such as transparent insulation substrates 31 such as glass substrate according to grid 32, gate insulating film 33, semiconductor layer 34, channel protective layer 35 with as the n of source electrode 36a and drain electrode 36b ⁺The order of silicon layer forms these parts.This film forms the method for the manufacturing active matrix substrate that step can be traditional and carries out.

After this, form nesa coating 37a, 37a ' and the metal level 37b, 37 ' that constitutes source electrode line 23 and connection electrode 25 in order, and make the figure of reservation shape by sputter.

With for example rotation coating photosensitive acrylic resin is coated onto on the substrate that obtains, it is thick to reach 3 μ m, forms insulating film of intermediate layer 38.According to predetermined pattern the resin bed that obtains is exposed under the illumination, develops with alkaline solution.The resin bed part of only exposing is formed the contact hole 26 of break-through insulating film of intermediate layer 38 by the alkaline solution etching.

Then, form nesa coating, and carry out design producing, form pixel electrode 21 by sputtering on the substrate that obtains.Therefore, each pixel electrode 21 is connected on the corresponding nesa coating 37a ' that contacts with TFT24 drain electrode 36b by the contact hole 26 of break-through insulating film of intermediate layer 38 formation.Like this, made this routine active matrix substrate.

The active matrix substrate of so making comprises pixel electrode 21 and includes thick insulating film of intermediate layer 38 between the buried layer of grid lead 22, source lead 23 and TFT24.This thick insulating film of intermediate layer has been arranged, just might be with grid and source lead 22 and 23 and the TFT24 pixel electrode 21 that overlaps.And, can make the plane to the surface of pixel electrode 21.As a result, when the transmission-type liquid crystal display device that comprises the liquid crystal layer between the active matrix substrate of so making, secondary substrate and two substrates is finished, can improve the aperture opening ratio of this device.And, owing to can shield the electric field that on lead-in wire 22 and 23, produces, so can make the incidence minimum of swing offset.

The specific inductive capacity of forming the acryl resin of insulating film of intermediate layer 38 is 3.4 to 3.8, is lower than the specific inductive capacity (for example, the specific inductive capacity of silicon nitride is 8) of inoranic membrane, and is high transparent.In addition, owing to used rotation to apply, reach 3 μ m so can easily obtain thickness.This has reduced between grid lead 22 and the pixel electrode 21 and the electric capacity between source electrode 23 and the pixel electrode 21, and time constant is little.Therefore reduced go between 22 and 23 and pixel electrode 21 between electric capacity to the influence of screen, such as cross (talk) etc., can obtain good and bright demonstration.

Contact hole 26 can be made into the taper of point by the pattern production process that comprises exposure and alkaline development.This helps between pixel electrode 21 and the nesa coating 37a ' better connectivity is arranged.

And, owing to used photosensitive acrylic resin, apply the thick film that can easily form several micron thickness by rotation.In the design producing step, do not need photoresist process.This is favourable to production.Though before applying the acryl resin as insulating film of intermediate layer 38 is dyeed, it also can make optical clear by after the design producing step whole surface being exposed under the illumination.Resin can also be made transparent with chemical method.

In the present embodiment, comprise i section (wavelength: 365nm), h section (wavelength: 405nm) and g section (wavelength: 436nm) under the ultraviolet light that the mercury lamp of emission spectrum sends being exposed to usually as the photosensitive resin of insulating film of intermediate layer 38.The i section has the highest energy (that is, wavelength is the shortest) in these emission light, therefore, be used in the photosensitive resin that has reaction peak (absorption peak) on the i section.This makes that forming contact hole accurately becomes possibility, and, because this peak away from visible light, therefore can make because the variable color minimum that photoresist causes.

The photosensitive resin that can also react with the ultraviolet light that the wavelength that excimer laser is sent is lacked.Use this painted insulating film of intermediate layer that do not have basically, can improve the transmissivity of the transmission-type liquid crystal display device that obtains.Thereby, can improve the brightness of liquid crystal display, perhaps owing to saved the power consumption that needed light quantity backlight can reduce LCD.

Because the thickness of insulating film of intermediate layer 38 reaches several microns, and is thicker than the insulating film of intermediate layer of traditional LCD, so preferably use the high as far as possible resin of transmissivity.Human eye is low to the visual sensitivity comparison green and the redness of blueness.Therefore, even the transmitted spectrum of this film is compared green to the transmissivity of blue light slightly and red light is low, display quality can not worsen basically.Though in this example the thickness of insulating film of intermediate layer 38 is made 3 μ m, it is not limited in 3 μ m.The thickness of insulating film of intermediate layer can be provided with according to the transmissivity and the specific inductive capacity of this film.In order to reduce electric capacity, this thickness better is to be equal to or greater than about 1.5 μ m, is more preferably and is equal to or greater than 2.0 μ m.

In this example, nesa coating 37a ' is made into the connection electrode 25 of drain electrode 36b and the corresponding pixel electrode 21 of each TFT24 of connection.Its advantage is as follows.In traditional active matrix substrate, connection electrode is made up of metal level.If in opening portion, form the metal connection electrode, will reduce aperture opening ratio.In order to overcome this problem, traditionally connection electrode is formed in the drain electrode of TFT or TFT.On connecting extremely, form contact hole, to connect drain electrode and the pixel electrode of TFT by insulating film of intermediate layer.Yet, for example, on less TFT, can not hold whole contact hole to TFT when making lessly when improving aperture opening ratio for this traditional structure.As a result, do not improve aperture opening ratio.Thick when reaching several microns when the thickness of insulating film of intermediate layer is made into, this contact hole should be tapered, and connecting pixel electrode and buried connection electrode, and needs bigger connection electrode in the TFT zone.For example, when the diameter of contact hole is 5 μ m, consider the contact hole and the calibration tolerance that attenuate, the size of connection electrode just should be about 14 μ m.On traditional active matrix substrate, if the size of TFT is worth less than this, oversize connection electrode will cause, reduce the new problem of aperture opening ratio.On the contrary, on this routine active matrix substrate, owing to connection electrode 25 is made up of nesa coating 37a ', so the trouble of aperture opening ratio can not occur reducing.And in this example, connection electrode 25 is extended the drain electrode 36b that connects TFT and the energy-storage capacitor electrode 25a of the energy-storage capacitor that formed by nesa coating 37a '.Because this extension is also formed by nesa coating 37a ', so this can not reduce aperture opening ratio yet.

In this example, source lead 23 belongs to the double-decker of being made up of transparency conducting layer 37a and metal level 37b.

If metal level 37b part defectiveness, source lead 23 still can keep electric conductivity by nesa coating 37a, so can reduce the generation that source electrode line 23 opens circuit.

Embodiment 2

In embodiment 2, will the another kind of method that form insulating film of intermediate layer 38 be described.

Until with identical with described in the embodiment 1 of sputter and graphical formation nesa coating 37a and the manufacturing process of 37a ' and metal level 37b and 37b '.Then, in this example, be coated in formation non-photosensitivity organic film on the structure that obtains by rotation.Then on this film, form photoresist, and printed patterns.With the photoresist of printed pattern, etching organic film, obtain insulating film of intermediate layer 38, and form contact hole 26 by this insulating film of intermediate layer 38.On the other hand, the non-photosensitivity organic membrane can apply by CVD rather than rotation and form.

The example of non-photosensitivity organic film comprises curable acrylate.More particularly, the JSS-924 (acryl resins of 2 component-types) and the JSS-925 (acryl resin of 1 component-type) that can make with Japanese synthetic rubber company limited.The thermal resistance of these resins is 280 ℃, and is perhaps higher.Insulating film of intermediate layer is convenient to carry out more random resin design with the non-photosensitivity resin.For example, can use polyimide resin.The example of clear, colorless polyimide resin comprises by such as 2, the acid anhydrides of two (dicarboxyl phenyl) the hexafluoropropylene acid anhydrides of 2-, oxydiphenyl diformic anhydride and diphenyl tetracarboxylic anhydride etc. with have sulfuryl and/or ether between substituted aromatic diamines or have the polyimide of the diamines combination acquisition of hexafluoro two thiazolinyls.These polyimide resins have description at the Nitto GihoVol.29 of people such as for example Fuiita work in the No.1 20-28 page or leaf (1991).One of above-mentioned clear, colorless polyimide resin, the resin that comprises each acid anhydrides that all has the hexafluoropropylene base and diamines has high transparency.Can also be with the fluorine resin that is different from above-mentioned fluorinated polyimide resin.Fluorine material not only has splendid water white transparency, also has low specific inductive capacity and high thermal resistance.

The photoresist that comprises silicon is carried out patterned photoresist with the insulating film of intermediate layer of being made by the non-photosensitivity organic material of opposing.When carrying out above-mentioned etching, the gas of the general available CF4 of comprising, CF3H, SF6 etc. carries out dry ecthing.Yet in this case, because photoresist and insulating film of intermediate layer all are organic resins, so be difficult to increase the selection rate between these resins.As in this example under the thick situation that reaches 1.5 μ m or thicker (near the thickness identical) of the thickness of insulating film of intermediate layer with photoresist especially.The rate of etch of these materials (being selectivity) is preferably different fully.When the combination of acryl resin and common photoresist during as insulating film of intermediate layer, selection rate for example is about 1.5.On the contrary, in this example, use to comprise the photoresist of silicon, so can obtain to be about 2.0 or bigger with respect to the selection rate of photosensitive acrylic resin.

On the other hand, carrying out design producing with the photoresist that does not comprise silicon when forming insulating film of intermediate layer, can be coated in silane bond (for example, hexamethyldisilazane) on the photoresist, and handle the silane bond with oxygen plasma, to form silicon oxide film.As a result, because the silicon oxide film on the photoresist is as diaphragm, so reduced the rate of etch of photic etchant.This method can be used together in conjunction with siliceous photoresist.

Above-mentioned method with element silicon improves selection rate and produces effect especially when carrying out dry ecthing with the gas that contains CF4, CF3H or SF6 etc.

As implement the example 1, the active matrix substrate that has the insulating film of intermediate layer 38 of formation like this also can provide high aperture opening ratio.

Non-photosensitivity organic film as insulating film of intermediate layer 38 has the normal and high grade of transparency of low dielectric in this example.

Its thickness can thickly reach 3 μ m.Distance is big between the electrode of the little and electric capacity of specific inductive capacity, can reduce between grid lead 22 and the pixel electrode 21 and the electric capacity between source lead 23 and the pixel electrode 21.

Embodiment 3

Fig. 3 is the planimetric map according to a pixel portion of the active matrix substrate of the transmission-type liquid crystal display device of embodiments of the invention 3.Fig. 4 is the sectional view along B-B ' line among Fig. 3.Parts with identical function and effect use with Fig. 1 and Fig. 2 in used identical reference number represent that description of them has just been omitted.

In this routine active matrix substrate, each contact hole 26a is formed on the storage capacitor electrode 25a and energy-storage capacitor consequent pole 27 of energy-storage capacitor of each pixel.With describe in the example 1 the same, the end of energy-storage capacitor electrode 25a formation connection electrode 25, it links to each other with the drain electrode 36b of TFT24.Another electrode of energy-storage capacitor (consequent pole 27 of energy-storage capacitor) is connected on the respective electrical container consequent pole that is formed on secondary substrate by energy-storage capacitor concentric line 6 shown in Figure 16.In other words, contact hole 26a is formed on the concentric line 6 of the energy-storage capacitor of being made up of the metal film of shading shielding.

The above-mentioned structure of this routine active matrix substrate has following advantage.

Because the thick 3 μ m that reach of thickness of insulating film of intermediate layer 38 for example, this is similar to the thick liquid crystal cells of 4.5 μ m, so be prone to light leakage phenomena because of the liquid crystal molecular orientation disturbance around contact hole 26a.If in the opening portion of transmission-type liquid crystal display device, form contact hole 26a, then because light leak will make contrast reduce.In other words, the active matrix substrate in this example does not have this trouble, and this is because each contact hole 26a is formed on the energy-storage capacitor electrode 25a and energy-storage capacitor consequent pole 27 as the end of the energy-storage capacitor concentric line 6 that is made of light tone metal film.In other words, as long as contact hole 26a is formed on the energy-storage capacitor concentric line 6 that is made of the shading metal film, and not in opening portion, the light leak around the contact hole 26a that the liquid crystal molecular orientation disturbance causes just can not reduce contrast.This also is suitable for the situation that the part of neighboring gates lead-in wire 22 is formed energy-storage capacitor as electrode.In this case, contact hole 26a is formed on the shading grid lead 22, therefore can prevent the reduction of contrast.

In this routine active matrix substrate, connect the drain electrode 36b of TFT24 and the connection electrode 25 of contact hole 26a and constitute by nesa coating 37a '.Thereby, can not reduce aperture opening ratio owing on energy-storage capacitor, forming contact hole 26a.

Therefore, in this example, because the capacitor consequent pole 27 that is formed under the contact hole 26a has covered light, so the light leak that the liquid crystal molecular orientation disturbance may cause can not influence demonstration.The size of contact hole 26a also needn't be very accurate, allows this hole big and smooth.As a result, the pixel electrode 21 that is formed on the insulating film of intermediate layer 38 is continuous, can not be touched hole 26a and interrupt.This has improved yield rate.

Embodiment 4

Fig. 5 is the fragmentary cross-sectional view according to the active matrix substrate of the transmission-type liquid crystal display device of embodiments of the invention 4.Have with Fig. 1 to Fig. 4 in the parts of identical function and effect use with these figure in used identical reference number represent that description of them has been omitted.

In this routine active matrix substrate, each contact hole 26b passes on the concentric line 6 that insulating film of intermediate layer 38 is formed on energy-storage capacitor.Under each contact hole 26b, nesa coating 37a goes up and forms metal nitride layer 41.

It is favourable that the active matrix substrate that this is routine above-mentioned is configured in following aspect.

At the resin that is used for insulating film of intermediate layer 38 be used for the ITO (tin indium oxide) of nesa coating or some troubles occur such as the bonding meeting between the metal of Ta and aluminium.For example, in the cleaning course after having formed contact hole 26b, clean solution is penetrated into surface of contact between resin and the lower floor's nesa coating from contact hole, causes that resin molding comes off from nesa coating.In order to overcome this trouble,, under contact hole on the nesa coating, form by TaN, AlN and the metal nitride layer 41 that has the similar material of good bonding to make with resin according to this routine active matrix substrate.Thereby, can prevent coming off and other bonding trouble of resin molding.

Any metal may be used to metal nitride layer 41, as long as it has and constitute the ITO of resin, formation nesa coating 37a ' of insulating film of intermediate layer 38 and similar material and such as good cementability is arranged between the metals such as Ta and Al.This metal also should conduct electricity, to be electrically connected nesa coating 37a ' and pixel electrode 21.

Embodiment 5

In embodiment 5, with the driving method of describing according to transmission-type liquid crystal display device of the present invention.

In transmission-type liquid crystal display device according to the present invention, each pixel electrode overlaps on the corresponding lead-in wire by insulating film of intermediate layer.If pixel electrode does not overlap on the corresponding lead-in wire, and is formed with the gap between them, then in liquid crystal layer, will form the zone that does not have electric field.This trouble can be by avoiding with lead-in wire imbrication pixel electrode.Electric field is not added on the liquid crystal layer zone corresponding to the border of adjacent pixel electrodes yet.Yet the existence of lead-in wire can be leaked by these regional contingent light of shutoff.This makes and there is no need to form black masks owing to considering active matrix substrate and the bonding error of secondary substrate on secondary substrate.This has improved aperture opening ratio.In addition, owing to can shield the worn-out electric field that on these lead-in wires, produces, so can make liquid crystal molecular orientation disturbance minimum.

Overlapping width should be considered the variation of actual manufacture process and be provided with.For example, be preferably and be about 1.0 μ m or bigger.

As mentioned above, when pixel electrode overlaps on the source lead since the electric capacity between pixel electrode and the source electrode line generation is crosstalked.This has reduced the display quality of the transmission-type liquid crystal display device that obtains.Especially, be used for showing that the influence that is subjected to the electric capacity between pixel electrode and the source lead is very big in the liquid crystal board of pixel with the notebook personal computer of vertical stripe shape arrangement.We think that this is owing to following reason: (1) because in vertical bar shaped distributes, pixel electrode be shaped as rectangle, its along one side of source lead for long limit, so the electric capacity between pixel electrode and the source lead is bigger; (2) because the color that shows is different between neighbor, so between the signal of transmission on the adjacent source lead-in wire, almost do not have correlativity.Therefore, can not eliminate the influence of the electric capacity between the adjacent source lead-in wire.

According to transmission-type liquid crystal display device of the present invention, the specific inductive capacity of the insulating film of intermediate layer that is made of organic film is less, and does thicklyer easily.Therefore, as mentioned above, can reduce the electric capacity between pixel electrode and these lead-in wires.Except these characteristics, according to this routine transmission liquid crystal display spare driving method, can reduce the influence of the electric capacity between pixel electrode and the source lead, make the vertical crosstalk minimum that takes place on the notebook personal computer.

This routine method comprises that the polarity by the data-signal on the every grid lead that reverses drives transmission-type liquid crystal display device (hereinafter this method being called " 1H inversion driving ").

Fig. 6 shows under the driving method of the polarity of 1H inversion driving and the every field reversal data-signal situation of (hereinafter this method being called " field reversal driving "), and the electric capacity between pixel electrode and the source electrode line is to the influence of pixel charge rate.Fig. 7 A and 7B show the 1H inversion driving respectively and field reversal drives the waveform that obtains.

In Fig. 6, Y-axis representative charging rate variance, the gray scale display part was added to the ratio that voltage on the liquid crystal layer is added to the effective value of the voltage on the liquid crystal layer when showing black window figure in the gray scale display part with 33% vertical occupation ratio when its expression uniform gray level showed.X-axis is represented capacity ratio, and the rate of change of the pixel electrode voltage that the electric capacity between it and pixel electrode and the source electrode line causes is proportional, can be represented by following formula (1):

Capacity ratio=Csd/ (Csd+Cls+Cs) ... (1)

Corresponding to the capacitance of the lcd segment of each pixel, Cs represented the capacitance of the energy-storage capacitor of each pixel when the capacitance between Csd remarked pixel electrode and the source electrode line wherein, Cls represented that gray scale shows.Gray scale shows and to refer to and be the demonstration that obtained in 50% o'clock in transmissivity.

Can observe from Fig. 6, in this routine 1H inversion driving, can be reduced to 1/5th to 1/10th of the capacitance influence that field reversal obtains in driving when identical to the electric capacity between pixel electrode and the source electrode line to the actual influence that is added to the effective voltage on the liquid crystal layer.This is because in the 1H inversion driving, the interval of inverted data signal polarity is enough shorter than the field duration of a field interval.This has eliminated positive signal and negative signal influence each other on display screen.

With diagonal line is that the VGA panel of 26cm shows test.From this test, can observe, when the charging rate variance is 0.6% or when bigger, crosstalking is significantly, has reduced display quality.In Fig. 6, dotted this situation.Can find in the curve from figure that in order to obtain 0.6% or littler charging rate variance, capacity ratio should be 10% or littler.

Fig. 8 shows the thickness of insulating film of intermediate layer during as a parameter, the relation between the electric capacity between overlapping degree between pixel electrode and the source lead and pixel electrode and the source lead.In this test, also use the VGA panel of diagonal line as 26cm.In test, acrylic acid photosensitive resin used among the embodiment 1 (specific inductive capacity is 3.4) is used as insulating film of intermediate layer.Consider machining precision, the overlapping width between pixel electrode and the source electrode line should be at least 1 μ m.Can find that from Fig. 6 and Fig. 8 the thickness of insulating film of intermediate layer should be 2.0 μ m or thicker, with the overlapping width that satisfies 1 μ m and 0.66% or littler charging rate variance.

Therefore, according to this routine 1H inversion driving, when overlapping on the source electrode line, pixel electrode still can obtain not have the good demonstration of vertical crosstalk and the polarity (source electrode line inversion driving) of signal on the adjacent source polar curve that need not to reverse.Thereby the present invention can be in notebook personal computer.

Find that also the some inversion driving has the identical effect that obtains with the 1H inversion driving.The point driving method is a kind of the signal of opposite polarity to be input on the pixel electrode adjacent one another are with horizontal direction, and the driving method of each horizontal scanning period reversed polarity.The source electrode line inversion driving as also effective during the quite low situation of above-mentioned capacity ratio.And, even when adjacent signals does not have the colored display operation of high correlativity each other, owing to greatly reduce according to the electric capacity between pixel electrode of the present invention and the source electrode line, so can suppress color cross talk.

Embodiment 6

In embodiment 6, with the another kind of driving method of describing according to transmission-type liquid crystal display device of the present invention.In the method, each grid lead counter-rotating is applied to the polarity of the voltage on the liquid crystal layer, and the reversal of poles by alternating voltage and source signal simultaneously synchronously drives the signal that is applied on the capacitor auxiliary electrode.The AC driving of this auxiliary electrode can make the amplitude minimum of source signal.

The curve that the Fig. 6 that describes among the embodiment 5 obtains when also showing with 5V amplitude alternating voltage driving auxiliary electrode.Can observe from Fig. 6, adjustment is bigger approximately by 10% than what obtain in embodiment 5 although the auxiliary electrode AC driving in this example makes charging, owing to used the 1H inversion driving, compares with the situation that field reversal drives, and this charging rate variance is still fully little.Therefore, as precedent, can realize not having the good demonstration of vertical crosstalk with this routine driving method.

Embodiment 7

Fig. 9 is the planimetric map of active matrix substrate one pixel portion of the transmission-type liquid crystal display device of embodiment 7.

In the transmission-type liquid crystal display device of this example, each smooth pixel electrode has covered corresponding lead-in wire to improve the aperture opening ratio of LCD, reduces the disturbance of liquid crystal peak value orientation as far as possible and has simplified manufacture process.And, reduce the influence such as crosstalking that electric capacity causes display between pixel electrode and the lead-in wire as much as possible, thereby obtained the display of function admirable.In this example, can obtain the mesosphere insulation film of highly transparent.Insulating film of intermediate layer is after overexposure and developing, and entire substrate all reacts with the useless photosensitizer with remainder through overexposure, and photosensitizer contains photosensitive transparent acrylic resin.

Referring to Fig. 9, the active matrix substrate comprises the some pixel electrodes 51 that are arranged in the matrix.Grid lead 52 and source lead 53 are walked along the mutual intersection of the periphery of pixel electrode 51.The periphery of each pixel electrode 51 has covered grid lead 52 and source lead 53.Be formed at the intersection point place of grid lead 52 and source lead 53 as the TFT54 of the on-off element that links to each other with development pixel electrode 51.Thereby being connected with grid lead 52, the grid of TFT54 makes of the driving of signal input grid with control TFT54.Thereby being connected with source lead 53, the source electrode of TFT54 makes data-signal input source electrode.The drain electrode of TFT54 links to each other with corresponding pixel electrode 51 with contact hole 56 through connection electrode 55.Drain electrode also is connected with the electrode (being storage capacitor electrode 55a) of storage capacitor through connection electrode 55.Another electrode of storage capacitor (being storage capacitor auxiliary electrode 57) is connected with public lead-in wire.

Figure 10 is for cuing open the sectional view of the active matrix substrate of getting along the sensing C-C ' of Fig. 9.

Referring to Figure 10, on transparent dielectric substrate 61, formed the grid 62 that links to each other with grid lead shown in Figure 9 52.Formed gate insulating film 63 cover grid 62.On grid insulating film 63, be formed with semiconductor layer 64,, and form channel protective layer 65 in the central authorities of semiconductor layer 64 so that grid 62 is superimposed with it through gate insulating film 63.Two n as source electrode 66a and drain electrode 66b ⁺-Si layer covers the end and semiconductor layer 65 parts of channel protective layer 65 after forming, thereby is separated from each other at the top of channel protective layer 65.Nesa coating 67a and metal level 67b as double-deck source lead 53 shown in Figure 9 form the back covering as another n ⁺The source electrode 66a of-Si layer.Nesa coating 67a ' and metal level 67b ' formation back cover as n ⁺The drain electrode 66b of-Si layer.Nesa coating 67a ' extends to and drains 66 and pixel electrode 51 is connected and as the connection electrode 55 that is connected with storage capacitor electrode 55a.After forming, insulating film of intermediate layer 68 covers TFT54, grid lead 52, source lead 53 and connection electrode 55.Insulating film of intermediate layer 68 is made up of the acryl resin (photosensitive transparent acrylic resin) of highly transparent, is dissolved in the developer solution after exposure.

Nesa coating is formed on the insulating film of intermediate layer 68 to constitute pixel electrode 51.The contact hole 56 of the nesa coating 67a ' of pixel electrode 51 through running through mesosphere insulation film 68 and connection electrode 55 is connected with the drain electrode 66b of TFT 54.

Active matrix substrate with said structure is made in the following manner.

At first according to following order on the transparent insulation substrate 61 such as glass substrate, form the grid 62 formed by Ta, Al, Mo, W, Cr etc., by SiNx, SiO ₂, Ta ₂O ₅Deng the gate insulating film of forming 63, semiconductor layer (intrinsic Si) 64, by SiNx, Ta ₂O ₅Deng the channel protective layer of forming 65, as the n of source electrode 66a and drain electrode 66b ⁺-Si layer.

After this utilize sputter to form nesa coating 67a and 67a ' successively and comprise Ta, Al, Mo, W, Cr etc. and constitute the metal level 67b and the 67b ' of source lead 53 and connection electrode 55, and print and go up predetermined pattern.In this example, the same with the example of front, source lead 53 is the double-deckers that are made of nesa coating 67a that comprises ITO and metal film 67b.Under such structure, if partly there is defective in metal level 67b, then source lead 53 still keeps electric conductivity by transparent conductive film 67a, thereby can reduce the possibility that source lead 53 disconnects.

The mode of utilizing rotation to apply, thus the photosensitive acrylic resin of 2 micron thickness is coated in formation insulating film of intermediate layer 68 on the said process resulting structures.The gained resin bed is by predetermined pattern exposure and develop in aqueous slkali.The part of an aqueous slkali etching exposure, thus the contact hole 56 that runs through insulating film of intermediate layer 68 formed.

Then, utilize sputtering method on insulating film of intermediate layer 68 and contact hole 56, to form transparent conducting film and impressing pattern to form pixel electrode 51.Like this, each pixel electrode 51 all is connected with transparent conducting film 67a ', and its contact hole 56 through running through insulating film of intermediate layer 68 contacts with the drain electrode 66b of TFT 54.So just produced the active matrix substrate of this example.

The mesosphere insulation film 68 of embodiment 7 is made up of positive glue type photosensitive acrylic resin, and it has good transparency and is dissolved in the developer solution after exposure.

The positive photosensitive acryl resin is reasonable for example be with the material formed by the multipolymer of methacrylic acid and glycidyl acrylate as raw polymer, and with the mixing of diazo naphthoquinone positive photosensitive agent.Owing to comprise the diglycidyl group in the resin, so can be by heating cross-linked (curing).Resin after solidifying has following character: specific inductive capacity is about 3.4; And the transmissivity in the 400-800nm wavelength coverage is more than 90%.Resin can discolor quickly under i-section (365nm) ultraviolet irradiation.Ultraviolet ray beyond the i-section can be in order to pattern exposure.Be generally 280 ℃ owing to be used for the thermal resistance of this routine photosensitive acrylic resin, so after 250-280 ℃ forms insulating film of intermediate layer down, form the performance degradation that pixel electrode can stop insulating film of intermediate layer again.

The process that the photosensitive acrylic resin that adopts above-mentioned highly transparent forms insulating film of intermediate layer 68 will be described in detail belows.

At first, utilize rotation to apply the solution that will comprise photosensitive clear acrylic material and be coated on the substrate, carry out general photoetching process subsequently successively, comprise that prebake, pattern exposure, alkali lye develop and pure water rinsing.

Particularly, utilizing rotation to be coated in to apply on the above-mentioned photoetching gained substrate solution that one deck comprises photosensitive transparent acrylic resin is 3 microns insulating film of intermediate layer 68 to form thickness.Thickness should be 1.5 microns at least.Particularly, the rotational speed coating viscosity with 900-1100rpm is the acryl resin of 29.0cp.Compare with common method, the flat pixels electrode that this just can obtain not have step makes the disturbance minimum of liquid crystal molecular orientation and has improved final display quality.

Then, final substrate is heated to about 100 ℃, with the photosensitive transparent acrylic resin solvent of mummification (for example Solactol salt, propyleneglycoles monomer ethyl acetate etc.).Final photosensitive acrylic resin develops according to predetermined pattern exposure and in aqueous slkali (trimethyl ammoniacal liquor is abbreviated as " TMAH ").The substrate of exposure partly is subjected to the erosion of aqueous slkali, thereby forms the contact hole 56 that runs through insulating film of intermediate layer 68.The concentration ratio of developer solution is preferably 0.1-1.0mol% (if TMAH).When concentration surpassed 1.0mol%, a large amount of unexposed photosensitive transparent acrylic resin parts also can be corroded, thereby were difficult to control the thickness of photosensitive transparent acrylic resin.When the concentration of developer solution during up to 2.4mol%, the acryl resin of corrosion part can stay residual substance, thereby causes contact to be lost efficacy.When concentration during less than 0.1mol%, along with the repeated use of developer solution, concentration can have greatly changed.So just make concentration be difficult to control.Remain in the developer solution of substrate surface subsequently with pure water rinsing.

As mentioned above, can utilize rotation to apply and form insulating film of intermediate layer.Therefore, make the film of several micron thickness do relatively evenly by selecting suitable rotating speed of whirler and the suitable viscosity of photosensitive transparent acrylic resin to be easy to.By selecting suitable exposure, solution level and development time can make contact hole be smooth taper.

Different according to the contained photosensitizer of photosensitive transparent acrylic resin (for example diazo naphthoquinone photosensitizer and the agent of diazo naphthoquinone positive photosensitive) type and quantity, the resin after developing can present shades of colour.For fear of this problem occurring, with the entire substrate exposure, allow in the resin contained useless painted photosensitizer chemically reactive fully, thereby the light absorption of elimination visibility region makes acryl resin transparent.The example of photosensitizer comprises diazonium naphthoxy type photosensitizer and the agent of diazo naphthoquinone positive photosensitive.

Figure 11 represent thickness be 3 microns acryl resin before and after the ultraviolet exposure its surface to the transmissivity of different wave length light.As seen from Figure 11, when resin did not expose, its transmissivity was 65% at wavelength 400nm place.After overexposure, transmissivity is brought up to more than 90%.In this case, substrate is subjected to the irradiation from front light.Adopt the method for pro and con while irradiation substrate to shorten the time shutter.

At last, the substrate of gained through heating to come cured resin by crosslinked.Particularly, substrate be placed on the flat plate heat or clean stove in and be heated to about 200 ℃ with cured resin.

Like this, utilize photosensitive transparent resin, can only carry out exposing patterns and print and need not conventional etching and the step of removing photoresist just can form insulating film of intermediate layer 68 and be used to connect the pixel electrode of on-off element and the contact hole 56 of drain electrode in insulating film of intermediate layer 68.This has simplified manufacture process.Photosensitive transparent acrylic resin can be that any numerical value in the 0.05-10 micrometer range (is 3 microns in embodiment 7; It should be noted that increase along with thickness, optical transmission rate reduce and color becomes obviously) and the viscosity by selecting resin solution and the rotating speed of whirler can obtain homogeneous thickness.

After this, utilize sputtering method also to print pattern to form pixel electrode 51 at the ITO that deposit 50-150nm is thick on the photosensitive transparent resin.As the thickness of each pixel electrode 51 is that the above ito thin film of 50nm can prevent to remove liquid solvent (for example dimethyl sulfoxide (DMSO)) effectively and infiltrates resin and prevent that resin from expanding because of the infiltration of reagent from the ito thin film surface gaps.So just produce the active matrix substrate of embodiment 7.

Therefore in the present embodiment, as the previous embodiment, owing to there is insulating film of intermediate layer 68, the part on the display panel except source lead and drain lead can be used as pixel perforate part.Final liquid crystal display device has bigger transmissivity and opening ratio, and brightness is higher.

And, be not subjected to the influence of the step of following lead-in wire and on-off element formation owing to exist mesosphere insulation film 68, pixel electrode can do more smoothly.This has been avoided the disconnection that pixel electrode takes place usually in drain electrode one side under the general case, thereby has reduced the quantity of defect pixel.Also avoided simultaneously the disturbance of the liquid crystal molecular orientation that step causes.In addition, because source lead 53 and pixel electrode 51 be spaced from each other by intermediate insulating film 68, so can reduce the quantity of the defect pixel that electric leakage causes between the source lead 53 and pixel electrode 51 under the general case.

And in this example, only need to form step with resin and replace film formation step, photoresist pattern in the ordinary skill to form step, etch step, striping step and cleaning step, just can form insulating film of intermediate layer 68.This has simplified manufacture process.

Embodiment 8

In example 8, what combine between the insulating film of intermediate layer 68 that will describe embodiment 7 shown in Fig. 9 and 10 and the buried layer film improves one's methods.

Because it is the character of buried layer membraneous material, possible relatively poor as combining between the photosensitive transparent acrylic resin of insulating film of intermediate layer 68 and the buried layer film.In this case; method according to this example; before applying photosensitive transparent acrylic resin; earlier with the buried layer film; be gate insulating film 63, channel protection film 65, source electrode 66a, drain electrode 66b, nesa coating 67a and 67a ' and metal film 67b and 67b '; under oxygen atmosphere, use M type mercury lamp (860W) ultraviolet light emitted, so that rough surface.On the rough surface of buried layer film, form the insulating film of intermediate layer 68 that photosensitive transparent acrylic resin is formed subsequently.Following step is the same with embodiment's 7.Utilize this method, combining between photosensitive transparent acrylic resin and the shaggy buried layer film is improved.This has overcome the insulating film of intermediate layer of being made up of photosensitive transparent acrylic resin 68 that occurs and the lower film problem of peeling off of film at the interface in ordinary skill.When this situation occurs in as the hydrochloric acid of corrosion ITO and iron chloride mixed solution infiltration interface.

Like this, by before forming insulating film of intermediate layer 68 with ultraviolet ray irradiation substrate surface, improved middle layer the combining between buried film 68 and the layer film of insulating.Although final devices also needs further manufacture process just can finish, but more stable.

According to the another kind of method of improving combination of the present invention is to use the silane connecting agent treatment surface before coated with resins.As the hexamethyl of silane coupling agent, disilazane, dimethyl two own oxygen bases, silane, n-butyl trimethoxy silane etc. for improving in conjunction with effective especially.For example if combine with silicon nitride film, then compare with the surface of handling without silane connecting agent, the bond strength of surface treated improves 10%.Utilize silane connecting agent to handle to avoid the damage of the resin pattern that the internal stress of bringing out because of resin crosslinks causes on undressed surface.

Before coated with resins, silane connecting agent can be sneaked in the resin rather than with reagent and be coated on the buried layer film.It is identical in conjunction with effect to utilize this method can obtain equally.Particularly, when the dimethyl lignocaine silane of 1% percentage by weight added photosensitive acrylic resin, silicon nitride film (being buried layer) had improved 70% with the bond strength of resin.

Embodiment 9

In embodiment 9, what combine between the insulating film of intermediate layer 68 that will describe embodiment 7 shown in Fig. 9 and 10 and the buried layer film improves one's methods.

Behind the insulating film of intermediate layer of forming by photosensitive transparent acrylic resin 68 in forming embodiment 7, utilize dry etching equipment in oxygen plasma atmosphere, to make the surface portion ashing of the thick insulating film of intermediate layer of 100-500nm 68.Particularly, in oxygen plasma atmosphere, utilize parallel plane type plasma etching equipment, be at RF power that 1.2KW, pressure are about 800m Torr, oxygen flow is about 300sccm, temperature is that 70 ℃ and RF application time are the surface of ashing acryl resin under the condition about 120 seconds.Utilize this technology, from the acryl resin surface, remove water and carbon dioxide, make rough surface thus by oxygenolysis.

Subsequently, utilize sputtering method ITO that deposit 50-150nm is thick on coarse photosensitive transparent acrylic resin and impressing pattern to form pixel electrode 51.So just produced the active matrix substrate.

Utilize this ashing method, pixel electrode 51 is improved with the combining of rough surface of the following insulating film of intermediate layer 68 that is made of photosensitive transparent acrylic resin.Utilize method for suppersonic cleaning that the interface is not peeled off.When acryl resin ashing surface portion thickness can't obtain above-mentioned effect during less than 100nm.When surpassing 500nm, photosensitive transparent acrylic resin thickness reduces too much, makes final acryl resin thickness degree change greatly, thereby causes the problem in the demonstration.Utilize any dry etching equipment (comprising barrel-shaped and RIE shape) in combination, all to obtain improvement.

Therefore, by before forming pixel electrode in oxygen plasma atmosphere the surface portion of ashing insulating film of intermediate layer 68, improved combining between insulating film of intermediate layer 68 and the pixel electrode material.Through further PROCESS FOR TREATMENT, final devices can be done more stablely.In addition, ashing is also very effective for remove residue from contact hole.This has reduced the possibility that comes in contact the hole disconnection.

In this example, the resin that is used for insulating film of intermediate layer carries out ashing again through after crosslinked.Owing in the cross linked chain step, can produce gas, so this helps carrying out cineration step under more stable condition.

Embodiment 10

Figure 14 is the planimetric map according to the active matrix substrate of the transmission-type liquid crystal display device of the embodiment of the invention 10.Figure 15 is for to cut open the sectional view of getting along pointing to D-D ' among Figure 14.With Fig. 1 and 2 function and the identical parts of effect with identical label, and omit description here.

In the active matrix substrate of present embodiment, the contact hole 26a through separating is connected with 26b between each TFT24 and the respective pixel electrode 21 and between each storage capacitor electrode 25a and the respective pixel electrode 21.And in this example, though can be sandwich construction, each source lead 23 still be made of single-layer metal.Storage capacitor electrode 25a by with previous embodiment in source lead 23 same materials constitute.Two contact hole 26a and 26b are formed on the metal electrode 23b of the drain electrode 36b that is connected TFT and on the storage capacitor electrode 25a.That is, these contact holes 26a and 26b be formed at can the metal electrode of shading on.

Transmission-type liquid crystal display device with said structure has following advantage.

The disturbance of liquid crystal molecular orientation for example when being 3 microns, the thickness of insulating film of intermediate layer 38 (is comparable to 4.5 microns of typical thickness of liquid crystal layer (structure cell thickness)), owing to can produce light and leak around contact hole 26a and 26b.If contact hole 26a and 26b are formed at the perforate part of transmission-type liquid crystal display device, then light leaks the reduction that has caused contrast.On the contrary, metal electrode 23b has stopped the light around the contact hole 26a because storage capacitor electrode 25a has stopped light around the contact hole 26b, so this routine active matrix such trouble can not occur.

By forming storage capacitor auxiliary electrode 27 and making these electricity, do not exceed storage capacitor electrode 25a, can further improve aperture opening ratio.Though what adopt in this example is common Cs (storage capacitor) type, also can adopt grid to meet Cs.

Like this, in the foregoing description 1-10, each pixel electrode has all covered corresponding lead-in wire to improve the aperture opening ratio of LCD, makes the liquid crystal molecular orientation disturbance minimum, and has simplified manufacture process.And the influence of electric capacity to showing such as crosstalking, also obtained overcoming to the full extent, thereby improved display quality between pixel electrode and the lead-in wire.Except These characteristics, also can obtain the visual angle of broad.

The acquisition at wide visual angle is based on following reason: (1) is because pixel electrode surface is more smooth, so the no longer disturbance of the orientation of liquid crystal molecule; (2) can upward not produce swing offset because of electric field is created on lead-in wire; (3) though the distance between the adjacent apertures part is 22 microns, utilize the mesosphere insulation film 38 of several micron thickness can effectively utilize the oblique ray of coming in the back side; (4) contrast big (is more than 1: 300 for 10.4 inches SVGA).Therefore can reduce hysteresis value, i.e. liquid-crystal refractive-index guidance quality (Δ n) * structure cell thickness (d).According to the present invention, the reducing mainly of retardance obtains by reducing structure cell thickness.Generally, along with reducing of Δ n * d, the visual angle will increase and contrast will descend.But, do pixel electrode bigger by the edge of eliminating between pixel electrode and the respective lead according to the present invention.For example, for 10.4 " VGA, aperture opening ratio becomes 86% from 65%, increased by 20 percentage points, and brightness has also increased by 1.5 times.Equally for 12.1 " XGA, aperture opening ratio sharply is increased to 80% from 50%.Its reason is as follows.In general structure, when the source lead width was 6 microns, the width between source lead and the pixel electrode was 3 microns, and attached edge is 5 microns, and the required distance between the adjacent apertures part reaches more than 22 microns.On the contrary, cover the structure of corresponding source lead according to each pixel electrode of the present invention, the distance between the adjacent apertures part can be identical with the source lead width, is 6 microns.Therefore can greatly reduce in the whole surface area the shared ratio of part beyond the perforate part.

The transmission-type liquid crystal pixel device of describing among the embodiment 3 and 4, wherein storage capacitor electrode (storage capacitor electrode) links to each other with its auxiliary electrode through the storage capacitor common lead.The grid lead 22 of neighborhood pixels also can be obtained the effect same that obtains by said structure as the storage capacitor electrode.Figure 12 and 13 shows the latter's structure.Such liquid crystal display device is called grid and connects the Cs type, and wherein each pixel electrode 21 covers grid lead 22 that its fronts or back be close to form storage capacitor Cs.In this case, pixel electrode 21 is reasonable is to cover the major part of a previous or back grid lead that is being close to it and cover the smaller portions that respective gates goes between.

In embodiment 1-10, utilize the method for spin-coating to apply the photosensitive transparent acrylic resin of highly transparent and impressing pattern forming insulating film of intermediate layer, and contact hole run through insulating film of intermediate layer.Except the spin-coating method, also can adopt other method (for example the rolling films and film in the slit) to apply photosensitive transparent acrylic resin.Utilize these methods also can obtain effect of the present invention.The method that rolling is filmed is that substrate is passed through between smooth cylinder of air spots and belt, and the substrate surface that will apply is facing to cylinder.The thickness of final coating depends on irregularity degree.The method of filming in the slit then makes substrate pass through under the spray seam.The thickness of final coating depends on the width of spray seam.

In embodiment 7 and 8,, only adopt the shortest i section of wavelength for i section (wavelength is 365nm), h section (wavelength is 405nm) and g section (wavelength the is 436nm) ultraviolet ray that exposure technology is used.This has shortened the time of photoirradiation, and particularly useful with making in the rough surface of embodiment 8 discoloring of embodiment 7.

Therefore according to the present invention, under the insulating film of intermediate layer structure, can form each pixel electrode and cover corresponding lead-in wire.This has improved aperture opening ratio and has made the disturbance of liquid crystal molecular orientation minimum.Because insulating film of intermediate layer is made of organic film, so compare with inorganic thin film, the less and thickness of its electric medium constant can be easy to do thick.So just can reduce the electric capacity between pixel electrode and the lead-in wire.Therefore, can reduce the vertical crosstalk that the electric capacity between pixel electrode and the source lead causes, and can make electric capacity causes between pixel electrode and the grid lead pixel write the voltage break-through to diminish, and reduce the variation in the manufacture process.

In the forming process of insulating film of intermediate layer, utilize a kind of coating method that the quick organic material of light Queensland such as acryl resin is coated on the substrate, again by exposure with develop to form pattern, be several microns organic film thereby obtained thickness with high rate of finished products.So just can increase and produce transmission-type liquid crystal display device under few situation with high aperture in manufacturing cost.The transmission-type liquid crystal display device that has than high aperture also can obtain according to following step: utilize deposit to form organic film, form photoresist on organic film, form organic Thinfilm pattern with etching method again.If be used for the resin of insulating film of intermediate layer color is arranged, then can after pattern forms, utilize the method for optics or chemistry to discolor, make resin transparent.Thereby, can get quality color monitor preferably.

Utilize nesa coating to be formed for connecting the drain electrode of TFT and the connection electrode of pixel electrode.This has further improved aperture opening ratio.This nesa coating can with have the double-deck source lead that comprises nesa coating and form simultaneously.Under double-decker, the disconnection of source lead can be avoided.

Each contact hole runs through the insulating film of intermediate layer that is positioned on storage capacitor common lead or the grid lead (being sweep trace).Because storage capacitor has partly stopped the light that the liquid crystal molecular orientation disturbance causes and has leaked, so improved contrast.In other words, if any, light leaks and results from shading light part, rather than in the perforate part.

Below running through each contact hole of insulating film of intermediate layer, can form metal nitride layer.This has improved combining between insulating film of intermediate layer and the buried layer.Like this, the liquid crystal display device of gained is more stable to further handling in the production run.

Each pixel electrode can cover corresponding source lead, and overlapping width is 1 micron or wideer.So just can make the aperture opening ratio maximum.And each pixel electrode needn't be very high with respect to the machining precision of respective lead.

Even this is because machining precision is not high, as long as pixel electrode covers lead-in wire, then overlapping lead-in wire will stop the leakage of light well.

The thickness of insulating film of intermediate layer is made 1.5 microns or thicker (reasonable is more than 2.0 microns), can make enough little of electric capacity between each pixel electrode and the corresponding source lead.Even the overlapping width of pixel electrode and source lead is 1 micron or wideer, such electric capacity has also reduced time constant.Therefore can reduce the influence of electric capacity to display, as crosstalk etc., thereby display quality preferably is provided.

Be reduced to below 10% by the capacity ratio that makes expression formula (1) and can further reduce vertical crosstalk, this is owing to fully reduced electric capacity between pixel electrode and the source lead.

The data-signal that source lead provides can every grid lead reversed polarity.This further reduces the influence of electric capacity to showing between pixel electrode and the corresponding source lead, as crosstalk etc.On the active matrix substrate pixel electrode is arranged as vertical strip and each pixel electrode is rectangular, the limit that wherein is parallel to source lead is parallel to the length of side of grid lead, so also can reach effect of the present invention.What can obtain being used for notebook personal computer etc. thus has big opening ratio and does not have the large scale liquid crystal pixel device of vertical crosstalk.

Utilization is much thinner that dielectric film has formed each storage capacitor than insulating film of intermediate layer.Though the memory capacitance area of gained is less, has bigger electric capacity.This has improved aperture opening ratio.Because storage capacitor electrode and source lead (being signal wire) form simultaneously, so can increase processing step.

When source lead was made of the shading conducting film, the contact hole part can stop light.These parts have been eliminated the disturbance of liquid crystal molecular orientation, thereby have improved display quality.This has also improved aperture opening ratio.

Under the situation that adopts the photosensitive resin that ultraviolet ray is reacted, if the reaction peak value of resin is positioned at the ultraviolet ray of i section, then contact hole can form accurately.And, because this peak value is from visible light farthest, so painted possibility minimum.This has improved the transmissivity of final transmission-type liquid crystal display device, thereby can reduce the back side illuminaton light intensity, saves energy, if do not reduce this intensity, then can improve brightness.

Owing to can do thicklyer comparatively speaking and more smooth, so overcome the problem that generally can cause when going between below forming, for example disconnection of pixel electrode drain side according to insulating film of intermediate layer of the present invention.Also avoided simultaneously the disturbance of liquid crystal aligning.Insulating film of intermediate layer separates pixel electrode and lead-in wire.This has reduced the quantity of the defect pixel that causes because of electric leakage between pixel electrode and the lead-in wire significantly, thereby has improved yield rate and reduced manufacturing cost.And, only need to form step and replace film formation step, photoresist pattern in the ordinary skill to form step, etch step, the step of removing photoresist and cleaning step and just can form insulating film of intermediate layer with resin according to the present invention.This has simplified manufacture process.

Can expose to entire substrate, thereby make insulating film of intermediate layer at the complete chemically reactive of useless photosensitizer that exposes and the quick transparent acrylic resin of post-develop comprises.So just obtained the insulating film of intermediate layer of highly transparent.

Can before forming insulating film of intermediate layer, use the ultraviolet irradiation substrate surface.This has improved combining between the exhausted Queensland velum in middle layer and the buried tunic.Thereby the gained liquid crystal display device is more stable to further handling in the production run.

The surface of insulating film of intermediate layer can ashing in oxygen plasma atmosphere before the pixel electrode material membrane forms.This has improved combining between insulating film of intermediate layer and the pixel electrode material film.Therefore, the gained liquid crystal display device is more stable to further handling in the production run.

The above pixel electrode of thickness 50nm can prevent effectively that the reagent as cleaning solution from infiltrating resin from the slit of film surface and because the infiltration of reagent makes the resin expansion.

Utilize the i section that energy is the strongest in the ultraviolet emission spectrum (wavelength is 365nm) can shorten the photoirradiation time and also improve the efficient of discoloring.

Along with the raising of display aperture ratio, its brightness has also obtained enhancing.Therefore under the prerequisite that does not reduce brightness, can widen the visual angle by reducing retardance.Obtained enough wide visual angle thus.

For the one of ordinary skilled in the art, be easy to the present invention is made various modifications and changes.So scope of the present invention, spirit are limited by the back claims.

Claims (12)

1. transmission-type liquid crystal display device is characterized in that it comprises:

Grid lead, the energy-storage capacitor concentric line, source lead, and be arranged near each grid lead and each source lead infall on-off element respectively, the grid of on-off element links to each other with grid lead, the source electrode of on-off element links to each other with source lead, the drain electrode of on-off element with voltage is applied to the pixel electrode that liquid crystal layer gets on and links to each other through connection electrode, described connection electrode is connected to described pixel electrode through contact hole, described contact hole is formed on directly over energy-storage capacitor concentric line or the grid lead

Wherein, one clear, colorless middle layer organic insulating film is arranged on on-off element, grid lead and the source lead, described clear, colorless middle layer organic insulating film is formed by photosensitive resin, and its thickness is determined by the light transmission and the specific inductive capacity of film, and described pixel electrode is the nesa coating on the organic insulating film of clear, colorless middle layer

Wherein, clear, colorless middle layer organic insulating film is littler than its spectral-transmission favtor for green glow and ruddiness for the spectral-transmission favtor of blue light.

2. transmission-type liquid crystal display device as claimed in claim 1 is characterized in that, the thickness of described clear, colorless middle layer organic insulating film is more than the 1.5 μ m.

3. transmission-type source electrode display device as claimed in claim 1 is characterized in that, described clear, colorless middle layer organic insulating film is a photosensitive acrylic resin.

4. transmission-type source electrode display device as claimed in claim 1 is characterized in that, described clear, colorless middle layer organic insulating film is the resin that discolors.

5. transmission-type source electrode display device as claimed in claim 1 is characterized in that described photosensitive resin is the positive photosensitive acryl resin.

6. transmission-type source electrode display device as claimed in claim 1 is characterized in that described photosensitive resin has the reaction peak value at wavelength 365nm place.

7. transmission-type source electrode display device as claimed in claim 1 is characterized in that, described photosensitive resin is exposed under the ultraviolet light that mercury lamp sends, and described mercury lamp comprises the i section of wavelength 365nm, the emission spectrum of the h section of wavelength 405nm and the g section of wavelength 436nm.

8. transmission-type source electrode display device as claimed in claim 7, it is characterized in that, described photosensitive resin is an acryl resin, and described acryl resin comprises multipolymer and the agent of diazo naphthoquinone class positive photosensitive with methacrylic acid and glycidyl methacrylate.

9. transmission-type source electrode display device as claimed in claim 8 is characterized in that described photosensitive resin is heat curing.

10. transmission-type source electrode display device as claimed in claim 1, it is characterized in that, described clear, colorless middle layer organic insulating film comprises photosensitive acrylic resin, described photosensitive acrylic resin comprises the multipolymer with methacrylic acid and glycidyl methacrylate, and the agent of diazo naphthoquinone class positive photosensitive.

11. transmission-type source electrode display device as claimed in claim 3, it is characterized in that, form under 250-280 ℃ temperature range after the organic insulating film of clear, colorless middle layer, described clear, colorless middle layer organic insulating film suppresses to degenerate by forming pixel electrode.

12. transmission-type source electrode display device as claimed in claim 3 is characterized in that, the photosensitive acrylic resin that is used to form described clear, colorless middle layer organic insulating film has 90% or higher light transmission to 400nm to the light in the 800nm wavelength coverage.

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