LOM OE ATAA
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`US 20080018816A1
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`as) United States
`2) Patent Application Publication (10) Pub. No.: US 2008/0018816 A1
`HATTORI etal.
`(43) Pub. Date:
`Jan. 24, 2008
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`Publication Classification
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`(54) LIQUID DISPLAY DEVICE AND
`FABRICATION METHOD THEREOF
`Inventors:
`Takashi HATTORI,
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`(76)
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`Museshimurayama (GP); Daisuke
`SONODA,Chiba (JP); Daisuke
`RYUZAKI, Hitachi (JP);
`Kazuyoshi TORIL
`Higashimurayama (JP)
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`Correspondence Address:
`MILES & STOCKBRIDGEPC
`1751 PINNACLEDRIVE, SUITE500
`MCLEAN,VA 22102-3833
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`(21) Appl. No.:
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`11/777,853
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`(22)
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`Filed:
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`Jul. 13, 2007
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`(30)
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`Foreign Application Priority Data
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`Int. Cl
`(51)
`(52) Cea
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`SS.
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`C1.
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`(2006.01)
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`349/39
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`ceeccccceeececseseeeseseseessnsesesesnecsssesceseeseees 349/:
`s
`ABSTRACT
`(57)
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`:
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`Aliquid crystal display improved with the opening ratio and
`increased for the storage capacitance,
`in which a gate
`insulating film, a gate electrode, an interlayer insulating
`film, an imageline and a source electrode are stacked inthis
`order formed in the layer above an active device formed to
`a first substrate, the interlayer insulating film is formed with
`a coatable transparent
`insulating film having a specific
`dielectric constant of4.0 or higher at least containing high
`dielectric fine particle or sol-gel, a first through hole is
`formed inthe gate insulating film, a second through holeis
`formed to the interlayer insulating film in the inside ofthe
`first through hole, the source electrode is electrically con-
`nected with the active device by way ofthe second through
`hole, and the storage capacitance is constituted bythe gate
`electrode,
`the image line,
`the source electrode, and the
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`Jul. 19, 2006
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`(IP) veeseecsessessessseeseestesseenes 2006-196375
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`interlayer insulating film.
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`Page 1 of 22
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`Tianma Exhibit 1009
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`Patent Application Publication
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`Jan. 24,2008 Sheet 1 of 7
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`US 2008/0018816 Al
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`FIG.
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`1
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`SH2~SH4
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`G
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`Patent Application Publication
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`Jan. 24,2008 Sheet 2 of 7
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`US 2008/0018816 Al
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`100B
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`100A
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`LC
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`Page 3 of 22
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`Patent Application Publication
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`Jan. 24,2008 Sheet 3 of 7
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`US 2008/0018816 Al
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`FIG. 5A
`p os
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`_
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`[T02
`|
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`FIG. 5B
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`aa
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`12C
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`3.2 4
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`FIG. 5C
`{|r~24
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`EXPOSUREayf
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`SS
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`FIG. 5D
`SH4
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`DEVELOPMENTaS
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`20
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`Patent Application Publication
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`Jan. 24,2008 Sheet 4 of 7
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`US 2008/0018816 Al
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`FIG. 6A
`SH3
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`D
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`ITO2
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`FIG. 6B
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`ae
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`3
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`2
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`4
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`FIG. 6C
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`25
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`12C:
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`COATING
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`FIG. 6D
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`24
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`EXPOSURE
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`FIG. 6E
`SH5
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`FIG. 6F
`SH4
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`20
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`DEVELOPMENT
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`ETCHING
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`FIG. 6G
`SH4
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`20
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`REMOVAL
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`Page 5 of 22
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`Patent Application Publication
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`Jan. 24,2008 Sheet 5 of 7
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`US 2008/0018816 Al
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`FIG. 7
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`TO"
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`Patent Application Publication
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`Jan. 24,2008 Sheet 6 of 7
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`US 2008/0018816 Al
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`FIG. 9
`TT
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`ITO3
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`EEE
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`ITO1
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`FIG. 10
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`ITO3 ITO!
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`13A
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`20
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`ITOQ2
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`Page 7 of 22
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`Patent Application Publication
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`Jan. 24,2008 Sheet 7 of 7
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`US 2008/0018816 Al
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`100B
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`FIG. 11
`CF
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`100A
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`US 2008/0018816 Al
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`Jan. 24, 2008
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`7135 (Patent Document 13), 2003-287883 (Patent Docu-
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`ment 14), 2003-288813 (Patent Document 15), and 2004-
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`14297
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`16) disclose photosensitive
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`material containing high-k dielectric fine particles, although
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`they are not concerned particularly with the IPS system.
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`SUMMARYOF THE INVENTION
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`[0008]
`In the active matrix type liquid crystal display, an
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`openingratio has been increased for improving high fineness
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`and saving consumption power. The IPS system liquid
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`crystal panel involves a problem in viewof the structure
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`thereof that improvement for the opening ratio is difficult
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`compared with the vertical electric field system.
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`Inthe IPS system liquid crystal display panel using
`[0009]
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`the planar counter electrode described above, a storage
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`capacitance (Cst) is formed with the planar counter elec-
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`trode, the pixel electrode having the linear portion and the
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`insulatingfilm therebetween. The storage capacitance serves
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`to morestably keeping static charges of the pixel electrode.
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`In the IPS systemreferred to herein, a storage capacitance
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`(Cst) formed so far in a not light transmitting portion is
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`formed in a light
`transmitting portion as a transparent
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`capacitancefilm. This can improve the openingratio. In this
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`case, a capacitor of high transparency, having a large capaci-
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`tance and a high withstand voltage is indispensable.
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`[0010] The capacitance C of a capacitor is represented by
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`the following formula (1)
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`C=E,E)S/d
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`(1)
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`In the formula (1), C: capacitance, ©: specific
`[0011]
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`dielectric constant,
`dielectric constant of vacuum, S:
`€,:
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`electrode area, d: inter-electrode distance.
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`[0012] Accordingly, for obtaining a large capacitance, it is
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`necessary to use a material of high-k dielectric constant,
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`increase the electrode area or decrease the inter-electrode
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`distance. For the electrode area, since high fineness is also
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`required, the size is limited. Particularly, in a medium-to-
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`small sized display,
`is indispensable to decrease the
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`electrode area for making it compatible with higherfineness.
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`Then, decrease of the inter-electrode distance is also limited
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`in viewof the problem for the control of the film thickness
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`or the problem of lowering the withstand voltage.
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`[0013] The present invention has been accomplished for
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`overcoming the problems in the prior art and it intends to
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`provide a capacitor of high transparency, having a high
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`capacitance and having a high withstand voltage. The fore-
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`going and other objects and novel features of the present
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`invention will become apparent in view ofthe descriptions
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`of the specification and the appended drawings to be
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`explained hereinafter.
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`[0014] The outline for the typical constitution of the
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`invention is as described below. That is, a liquid crystal
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`display according to the invention includes:
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`(1) a first substrate, a second substrate, and liquid crystals
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`put betweenthe first substrate and the second substrate, in
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`which
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`the first substrate includes an active device, a first
`[0015]
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`insulating film disposed to a layer above the active device,
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`a first electrode disposed to a layer abovethefirst insulating
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`film, a second insulating film disposed to a layer above the
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`first electrode, and a second electrode disposed to a layer
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`above the second insulating film,
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`LIQUID DISPLAY DEVICE AND
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`FABRICATION METHOD THEREOF
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`CLAIM OF PRIORITY
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`[0001]
`‘The present application claims priority from Japa-
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`nese application JP 2006-196375 filed on Jul. 19, 2006, the
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`content of which is hereby incorporated by reference into
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`this application.
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`FIELD OF THE INVENTION
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`[0002] The present invention concerns a liquid crystal
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`display and a fabrication method thereofand,particularly, it
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`is suilable to a substrate formed with an active device
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`(typically, thin film transistor) of a liquid crystal display
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`panel constituting a display portion of a liquid crystal
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`display.
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`BACKGROUND OF THE INVENTION
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`[0003] An active matrix type liquid crystal display using
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`active devices typically represented by thinfilm transistors
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`(TFT) has been popularized generally as various types of
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`displays in view of the feature of reduced thickness and
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`weight and high picture quality. The display system of the
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`liquid crystal display is generally classified into the follow-
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`ing two types. One of them is a system of sandwiching liquid
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`crystals between two substrates constituted each with a
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`transparent electrode, conducting operation by a voltage
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`applied to the transparent electrodes and displaying, under
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`modification, a light transmitting the transparent electrode
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`and incident to the liquid crystals, and most of products
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`popularized at present adopt this vertical electric field sys-
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`[0004] The other of them is a system referred to as a
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`transverse electric field system or an in-plane switching
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`(IPS) system. The IPS systemliquid crystal display panelis
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`adapted to generate a electric field which is parallel with a
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`substrate surface in at least a portion thereofbetween a pixel
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`electrode and a counter electrode and display images by
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`driving liquid crystals by the electric field thereby modifying
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`a light transmitting a liquid crystal layer, and it has a feature
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`that a field angle is remarkably wide. The feature of the
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`aclive matrix type liquid crystal display adopting the IPS
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`system is described in JP-T No. 5-505247 and JP-T No.
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`6-160878 (Patent Documents 1 and 2).
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`Further, in the IPS system liquid crystal display
`[0005]
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`panel, it has been knowna liquid crystal display panel of
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`forming a planar counter electrode and a pixel electrode
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`having a linear portion sandwiching an insulating film,
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`generating an electric field between the planar counter
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`electrode and the pixel electrode having the linear portion,
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`driving the liquid crystal by the electric field and displaying
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`an image by modifying a light transmitting a liquid crystal
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`layer.
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`[0006] Although not particularly relating to the IPS sys-
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`tem, prior art documents concerned with the present inven-
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`tion include JP-A Nos. 5-61057 (Patent Document 3),
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`6-138484 (Patent Document 4), 8-152650 (Patent Document
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`5), 9-90341 (Patent Document 6), 2000-310793 (Patent
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`Document 7), 2001-13518 (Patent Document 8), 2006-
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`18326 (Patent Document 9), 9-127548 (Patent Document
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`10), and 6-242433 (Patent Document 11).
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`[0007]
`Further, as prior art documents concerned with the
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`present invention, 2000-30534 (Patent Document 12), 2003-
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`Page 9 of 22
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`Page 9 of 22
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`US 2008/0018816 Al
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`Jan. 24, 2008
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`[0016]
`the secondinsulating film is a coatable transparent
`in any one of (1) to (10) according to the
`(11) Further,
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`insulating layer having a specific dielectric constant of 4.0 or
`invention, the second insulating film can have a transmit-
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`higher,
`tance of 90% or more at a wavelength of 450 nm or more and
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`800 nm orless.
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`[0017] the first insulating film hasafirst contact hole,
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`the second insulating film is formed between the
`[0018]
`(12) Further,
`in any one of (1) to (11) according to the
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`first electrode and the second electrode, and in the first
`invention, the first electrode can be a transparent electrode.
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`contact hole,
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`(13) Further, in any one of (1) to (11) according to the
`[0019]
`a second contact hole is formed to the second
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`invention, the first electrode can be a reflection electrode.
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`insulating film in the inside of the first contact hole,
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`(14) Further, in (13) according to the invention, the reflec-
`the second electrode is a pixel electrode,
`[0020]
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`tion electrode can have unevenness therein.
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`the second electrode is electrically connected by
`[0021]
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`way of the second contact hole with the active device, and
`(15) Further, in any one of (1) to (11) according to the
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`[0022]
`a storage capacitance is formed bythefirst clec-
`invention, the first electrode can be a transparent electrode
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`and a reflection electrode.
`trode, the second electrode, and the second insulating film.
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`to (15) according to the
`(16) Further, any one of (1)
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`invention can be adapted such that the first electrode is a
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`counter electrode and the liquid crystals are driven by an
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`electric field generated by thefirst electrode and the second
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`electrode.
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`(2) Further, in (1) according to the invention, the second
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`electrode can be a transparent electrode.
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`[0023]
`(3) Further, in (1) or (2) accordingto the invention,
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`the second insulating film can contain at least a transparent
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`film constituting a main material thereof and fine particles
`
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`
`
`
`
`
`having a specific dielectric constant higher than that of the
`
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`transparent film material.
`
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`(17) l'urther, in (16) according to the invention, a slit can be
`
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`
`formedto thefirst electrode.
`
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`
`[0026]
`Further, any one of (1) to (15) according to the
`
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`
`
`
`invention can be adapted such that the second electrode is a
`
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`
`
`counter electrode and the liquid crystals are driven by an
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`electric field generated by the counter electrode and the
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`second electrode.
`
`
`in any one of (1) to (18) according to the
`(18) Further,
`
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`
`
`
`invention, a third insulating film can be disposed between
`
`
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`
`
`the first electrode and the second electrode.
`
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`
`
`(20) Further, in any one of(1) to (19) according to the
`
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`
`
`invention, the surface of the second insulating film can be
`
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`made planar.
`
`
`[0027]
`(21) Then, a method offabricating a liquid crystal
`
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`
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`
`
`
`
`display device according to the invention includes a process
`
`
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`
`
`
`of:
`
`forming an active device on the main surface of the
`[0028]
`
`
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`
`
`
`first substrate,
`
`
`stacking a first insulating film, a first electrode, a
`[0029]
`
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`
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`
`
`second insulating film, and a second electrode in this order
`
`
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`
`in the layer above the active device,
`
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`
`forming the secondinsulating film betweenthefirst
`[0030]
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`
`electrode and the second electrode and in the inside of the
`
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`first through hole by using a coatable transparent insulating
`
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`film having a specific dielectric constant of 4.0 or higher,
`
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`
`[0031]
`forming a second through hole to the second insu-
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`
`lating film inthe inside ofthe first through hole,
`
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`
`[0032]
`electrically connecting the second electrode con-
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`
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`
`stituting a pixel electrode by wayof the second contact hole
`
`
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`to the active device, and
`
`
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`
`
`[0033]
`forming a storage capacitanceby thefirst electrode,
`
`
`
`
`
`
`
`
`in
`the second electrode, and the second insulating film,
`
`
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`
`
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`
`
`whichthe second insulating film is made photosensitive, and
`
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`
`exposure and development in a predetermined pattern are
`
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`
`
`applied to the second insulating film to form the second
`
`
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`
`
`
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`
`
`through holes.
`
`
`[0034] The constitutions described in (1) to (21) above are
`
`
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`
`
`
`
`
`
`only examples and the invention is not restricted to them.
`
`
`
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`
`
`
`
`
`
`[0035]
`[Specific dielectric constant], [material], [fine par-
`
`
`
`
`
`
`
`[grain size],
`ticles],
`[sol-gel],
`[photosensitivity],
`[mixing
`
`
`
`
`
`ratio], [film thickness], [transmittance], [refractive index],
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`(4) Further, in (3) according to the invention, the grain size
`
`
`
`
`
`
`
`
`
`
`
`of the fine particles having the specific diclectric constant
`
`
`
`
`
`
`
`
`higher than that of the transparentfilm material can be 30 nm
`
`
`
`
`
`
`
`
`
`
`
`orless.
`
`
`(5) Further, in (3) or (4) according to the invention, the fine
`
`
`
`
`
`
`
`
`
`
`
`
`particles having the specific dielectric constant higher than
`
`
`
`
`
`
`
`
`that of the transparent film material can use the following
`
`
`
`
`
`
`
`
`
`
`material (a):
`
`
`
`
`
`
`
`[0024]
`titanium oxide, barium titanate, aluminum
`(a)
`
`
`
`
`
`
`
`oxide,
`tantalum oxide, zirconium oxide, hafnium oxide,
`
`
`
`
`
`
`
`niobium oxide, and yttrium oxide. They may be used each
`
`
`
`
`
`
`
`
`
`
`alone or two or more of them maybe used in admixture.
`
`
`
`
`
`
`
`
`
`
`
`
`(6) Further,
`in (1) or (2) according to the invention, the
`
`
`
`
`
`
`
`
`
`
`
`second insulating film can be a material at least containing
`
`
`
`
`
`
`
`
`
`a transparent film constituting a main material thereof and a
`
`
`
`
`
`
`
`
`sol-gel having a specific dielectric constant higher than that
`
`
`
`
`
`
`
`
`of the transparent film material.
`
`
`
`
`
`
`
`(7) Further, in (6) according to the invention, the sol-gel
`
`
`
`
`
`
`
`
`
`
`having a specific dielectric constant higher than that of the
`
`
`
`
`
`
`
`
`
`
`transparent film material can use the following material (a)
`
`
`
`
`
`
`
`
`
`[0025]
`(a)
`titanium oxide, barium titanate, aluminum
`
`
`
`
`
`
`
`oxide,
`tantalum oxide, zirconium oxide, hafnium oxide,
`
`
`
`
`
`
`
`niobium oxide, and yttrium oxide. They may be used each
`
`
`
`
`
`
`
`
`
`
`alone or two or more of them maybe used in admixture.
`
`
`
`
`
`
`
`
`
`
`
`
`(8) Further,
`in any one of (3) to (7) according to the
`
`
`
`
`
`
`
`
`
`
`
`invention, the transparent film constituting the main material
`
`
`
`
`
`
`
`can contain at least a polymer selected from polyacrylate
`
`
`
`
`
`
`
`
`derivatives, polystyrene derivatives, polyolefin derivatives,
`
`
`
`
`and copolymersthereof.
`
`
`
`
`
`
`
`
`
`in any one of (3) to (7) according to the
`(9) Further,
`
`
`
`
`
`
`
`
`
`
`
`invention, the transparentfilm constituting the main material
`
`
`
`
`
`
`
`can be a material having photosensitivity.
`
`
`
`
`
`
`(10) Further,
`in any one of (1)
`to (9) according to the
`
`
`
`
`
`
`
`
`
`
`
`invention, the thickness of the second insulating film can be
`
`
`
`
`
`
`
`
`
`100 nm or more and 1000 nm orless.
`
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`
`Page 10 of 22
`
`Page 10 of 22
`
`

`

`US 2008/0018816 Al
`
`Jan. 24, 2008
`
`[planarity], etc. in the typical constitutional examples of the
`invention described above are to be explained.
`
`[Specific Dielectric Constant}:
`
`[0036] The coatable transparent insulating film having the
`specific dielectric constant of 4.0 or higher includes those
`materials containing at least a transparent film constituting
`the main material thereof, fine particles or a sol-gel having
`a specific dielectric constant higher than that ofthe trans-
`parent
`film material. The specific dielectric constant
`is,
`preferably, 4.0 or higher and, preferably, 6.0 or higher. The
`reason is as described below.
`[0037] That is, fineness has madehigheralso in a medium-
`to-small sized liquid crystal displays typically represented
`by the liquid crystal panel of a mobile telephone and it is
`considered that QVGA (320x240 pixels) at present will shift
`to VGA (640x480pixel) class in the feature. Considering a
`2.4 inch (nominal) panel of VGA and assuming that a
`storage capacitance of 60 {F is necessary and the electrode
`area thereof is 400 um?. Theinter-electrode distance d is
`about 195 nm ina case of using a material having a specific
`dielectric constant of 4.0 or less, for example, a coatable
`insulating film such as of an acrylate polymer having a
`specific dielectric constant of 3.3 knownsofar according to
`the relation:
`
`C=E,E,S/d
`
`()
`
`more of them may be used in admixture. The specific
`dielectric constant of the polymers is about from 3 to 3.5.
`Further, the polymers can be mixed with a photosensitive
`ingredient for providing the photosensitivity. Further, a
`photosensitive ingredient may be directly attached to the
`polymer.
`
`[Fine Particles]:
`
`In the coatable transparentinsulating film having a
`[0041]
`specific dielectric constant of 4.0 or higher, the fine particles
`having a specific dielectric constant higher than that of the
`transparent film material include metal oxides suchas tita-
`nium oxide (TiO), aluminum oxide (Al,O,), barium titan-
`ate (BaTiO,),
`tantalum oxide (Ta,O;), zirconium oxide
`(ZrO,), hafnium oxide (HfO,), niobium oxide (Nb,O,), and
`yttrium oxide (Y,O,). Further they also include metal
`nitrides of high specific dielectric constant, for example,
`silicon nitride (Si,N.,). Such fine particles may be used each
`alone, or twoor more ofthem maybe used in admixture. The
`following Table 1 showsdielectric materials and features
`thereof.
`
` TABLE1
`
`High
`dielectric
`material
`
`Chemical
`formula
`
`Specific
`dielectric
`constant
`
`Refraction
`index
`
`Feature
`
`Titanium
`oxide
`
`Barium
`titanate
`
`TiO,
`
`X,y =8.1,
`z=173
`
`2.3-2.55
`
`BaTiO;
`
`1200-2900
`
`2.3-2.4
`
`Ta,Os5
`
`25
`
`2.16
`
`Zirconium=ZrO» 11-18.5 2.05 Highly
`
`
`
`specific dielectric constant,
`(in which C: capacitance, €,:
`Inexpensive,
`high
`€,: dielectric constant of vacuum,S: electrode area, d: inter
`transparent
`electrode distance), Accordingly,
`it is necessary to control
`Extremely
`the thickness ofthe coatable insulating film to about 200 nm.
`high
`dielectric
`[0038] As shown in the formula (1) above, since the
`constant
`capacitance C andthe electrode areaSare in proportion, the
`Aluminun
` Al,O;
`8.5-10
`1.67
`Inexpensive,
`capacitance can be made larger whenthe electrode area can
`oxide
`high
`be enlarged. However, decrease of the electrode area is
`transparent
`limited in view ofthe trend of making the fineness higher as
`Tantalum
`oxide
`has been described above. Since the inter-electrode distance
`
`
`d is in an inverse proportionto the capacitance, it is possible
`oxide
`transparent
`to improve the capacitance by decreasing the inter-electrode
`Hafnium
`oxide
`distance (d). However,the withstand voltage and the leakage
`Yttrium
`current provide a problem in this case. Actually,
`in an
`oxide
`organic film at a film thickness of about 200 nm, it may be
`Niobium
`oxide
`a high possibility that the withstand voltage and the leak
`current result in the problem.
`Silicon
`oxide
`[0039] On the contrary,
`in a case of using a material
`having a specific dielectric constant, for example, of 5.0, the
`inter-electrode distance is 300 nm according to the formula
`(1) andthis is advantageous in view of the withstand voltage
`and the leakage current by so muchas the thickness can be
`increased. In a case where the dielectric constant is further
`higher, the effect is further improved.
`
`HfO,
`
`Y,0;
`
`Nb,Os
`
`SiaNy
`
`1.95
`
`1.87
`
`2.33
`
`24
`
`ll
`
`46
`
`7-8
`
`[Grain Size]:
`
`the
`In a case of adding them as fine particles,
`[0042]
`primary grain size thereof is, preferably, 30 nm orless and,
`more preferably, 20 nmorless. In a case where thegrain size
`is larger than that described above, the light scattering effect
`tends to increase and a transparentfilmis difficult to obtain.
`On the other hand, even whenthe primary grain size is
`small, agglomeration may cause scattering. those not caus-
`ing agglomeration are desirable.
`[0043]
`Further, depending on the material, someactivity is
`shown sometimes. For example, referring to TiO,, it has
`been knownthat crystals of an anatase type show photo-
`catalytic activity. However, since the activity may lead to the
`deterioration ofthe material thus giving undesired effects in
`the application use ofthe invention, those of arutile type
`showingless photocatalytic activity are desired. Further,it is
`
`[Material] (Organic Polymer):
`
`[0040] For the coatable transparentinsulating film having
`a specific dielectric constant of 4.0 or higher used in the
`invention, the transparent film constituting the main portion
`thereof includes polyacrylate derivatives, polymethacrylate
`derivatives, polystyrene derivatives, polyolefin derivatives,
`and copolymers thereof. Those other than described above
`can also be used so long as they are highlytransparent in a
`visible region and not colored by a heat treatment at about
`200° C. For the molecular weight, those having a weight
`average molecular weight of about 1,000 to 100,000 are
`preferred. Such polymers can be used each alone or two or
`
`Page 11 of 22
`
`

`

`US 2008/0018816 Al
`
`
`
`
`
`Jan. 24, 2008
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`sensitivity, it is necessary for coating and curing the coatable
`
`
`
`
`
`
`
`
`
`transparent insulating film, then coating additionally a pho-
`
`
`
`
`
`
`tosensitive photoresist or the like to the upper layer, baking,
`
`
`
`
`
`
`
`
`
`
`exposing and developing the sameto form a pattern. Further,
`
`
`
`
`
`
`
`
`
`since it is necessary to etch the coatable transparent insu-
`
`
`
`
`
`
`
`
`
`lating film in the lower layer using the resist as a mask,
`
`
`
`
`
`
`
`
`
`
`
`
`transfer the pattern and,finally, remove the photoresist in the
`
`
`
`
`
`
`
`
`
`
`upper layer, this makes the step lengthy.
`
`
`
`
`
`
`
`[0050] On the other hand, in a case where the coatable
`
`
`
`
`
`
`
`
`
`
`transparent insulating film having a dielectric specific con-
`
`
`
`
`
`
`
`stant of 4.0 or higher has a photosensilivily, since the film
`
`
`
`
`
`
`
`
`
`
`
`per se is sensitive to the light,
`it can be coated, baked,
`
`
`
`
`
`
`
`
`
`
`
`
`exposed and developed to form a pattern and the step is
`
`
`
`
`
`
`
`
`
`
`
`completed by the subsequent photo-bleaching and curing.
`
`
`
`
`
`
`
`Accordingly, this is advantageous since the pattern can be
`
`
`
`
`
`
`
`
`
`formed simply and conveniently.
`
`
`
`
`[0051] For providing the coatable transparent insulating
`
`
`
`
`
`
`
`film with the photosensitivity, the binder for the organic
`
`
`
`
`
`
`
`
`
`polymer described above includes, for example, those con-
`
`
`
`
`
`
`
`taining at least a polymer using an alkali soluble unit such
`
`
`
`
`
`
`
`
`
`
`as a carboxylic acid and a diazonaphthoquinone as a pho-
`
`
`
`
`
`
`
`
`
`tosensitizer. In such material, since diazonaphthoquinoneis
`
`
`
`
`
`
`
`decomposed by exposure and transformed into indene car-
`
`
`
`
`
`
`
`boxylic acid to increase the alkali solubility, the exposed
`
`
`
`
`
`
`
`
`portion is removed by alkali development to obtain a posi-
`
`
`
`
`
`
`
`
`
`tive type pattern.
`
`
`
`[0052]
`Further, the binder of the organic polymer can be
`
`
`
`
`
`
`
`
`
`
`incorporated with epoxy units that cause heat crosslinking or
`
`
`
`
`
`
`
`
`
`polymerizable units such as acrylate units on the side chains
`
`
`
`
`
`
`
`
`
`
`for curing the film after forming the pattern by exposure and
`
`
`
`
`
`
`
`
`
`
`
`development.
`
`[0053] Another method of providing the photosensitivity,
`
`
`
`
`
`
`
`an alkali soluble unit such as a carboxylic acid is used as a
`
`
`
`
`
`
`
`
`
`
`
`
`
`binder for the organic polymer described above and a
`
`
`
`
`
`
`
`
`
`polymer having photo-reactive units groups such as acrylate
`
`
`
`
`
`
`
`
`units or methacrylate units on the side chains are used and
`
`
`
`
`
`
`
`
`
`
`
`a photo-initiator and, optionally, a polyfunctional photo-
`
`
`
`
`
`
`reactive oligomer are incorporated. By using such a mate-
`
`
`
`
`
`
`
`
`rial, photopolymerization is initiated by exposure to cause
`
`
`
`
`
`
`
`crosslinking in the exposed portion and a not exposed
`
`
`
`
`
`
`
`
`portion is removed by alkali developmentto obtain a nega-
`
`
`
`
`
`
`
`
`tive type pattern.
`
`
`
`[Photosensitive Sol-Gel]:
`
`
`[0054]
`Ina case of using a sol-gel of a metal oxide as a
`
`
`
`
`
`
`
`
`
`
`
`high-k dielectric material having a specific dielectric con-
`
`
`
`
`
`
`
`stant 5.0 or more, for example, TiO,, Al,O;, BaTiO3, Ta,O;,
`
`
`
`
`
`
`
`
`
`
`ZrO,, ZnO, HfO,, Nb,O,, and Y,O;, since sol-gel can
`
`
`
`
`
`
`
`
`
`providebyitself a transparent coating film, it can be used as
`
`
`
`
`
`
`
`
`
`
`
`a photosensitive material by incorporation of a photosensi-
`
`
`
`
`
`
`tive ingredient thereto. Specifically, a negative type photo-
`
`
`
`
`
`
`
`sensitive composition in which the exposed portion is ren-
`
`
`
`
`
`
`
`
`dered insoluble can be formed by adding a photo-acid
`
`
`
`
`
`
`
`
`
`generator such as an oniumsalt, or sulfonic and imide.
`
`
`
`
`
`
`
`
`
`
`Further, a positive type photosensitive composition improv-
`
`
`
`
`
`
`ing the solubility of the exposed portion can also be formed
`
`
`
`
`
`
`
`
`
`
`
`by a diazonaphthoquinone type material.
`
`
`
`
`
`
`
`[Mixing Ratio]:
`
`
`[0055] The ratio of the fine particles or the sol-gel having
`
`
`
`
`
`
`
`
`
`
`a specific dielectric constant higher than that of the trans-
`
`
`
`
`
`
`
`
`
`parent film material relative to the transparent film consti-
`
`
`
`
`
`
`
`
`tuting the main body of the invention can be varied option-
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`also preferred that the periphery of the particle is covered
`
`
`
`
`
`
`
`
`
`with a more stable material such as SiO, or Al,O,.
`
`
`
`
`
`
`
`
`
`[0044]
`For avoiding agglomeration of the fine particles,
`
`
`
`
`
`
`
`
`
`the fine particle of high-k dielectric material used in the
`
`
`
`
`
`
`
`
`
`
`invention is preferably treated with a surface treating agent
`
`
`
`
`
`
`
`
`further at the periphery thereof. The fine particles are coated
`
`
`
`
`
`
`
`
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`optionally in admixture with a binderor an organic polymer
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`as the photosensitive ingredient in an appropriate solvent.
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`Accordingly, for improving the dispersibility of them in the
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`solution,
`those applied with a surface treatment by an
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`appropriate surface treating agent are preferred. Specific
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`surface treating agent includes, for example, silane coupling
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`reagents, polysilicon derivatives and stearic acid.
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`[Sol-Gel]:
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`[0045]
`‘The coatable transparent insulating film having a
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`specific dielectric constant of 4.0 or higher used in the
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`invention may be those containing a sol-gel having a specific
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`dielectric constant higher than that of the transparent film
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`material. The sol-gel includes those of metal oxides sol-gel
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`such as titanium oxide (TiO,), aluminum oxide (A1,O,),
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`bariumtitanate (BaTiO,), tantalum oxide (Ta,O,), zirco-
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`nium oxide (ZrO,), hafnium oxide (HfO,), niobium oxide
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`(Nb,O,), and yttrium oxide (Y,0,). The sol-gel may be used
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`alone or two or more kinds thereof may be used in admix-
`ture.
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`[0046]
`Inthe case ofthe sol-gel, since this is not a particle
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`it has less effect of scattering a light and has a feature that
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`a transparent film can be obtained easily. However, in a case
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`where a coatable transparent insulating film having a spe-
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`cific dielectric constant of 4.0 or higher is a photosensitive
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`material, the sol-gel tends to give an effect on the developing
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`property of the film. The sol-gel may also be used together
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`with the fine particles shown previously.
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`[0047]
`Further, in the case ofthe sol-gel, it can sometimes
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`form a coating film by itself. Accordingly, in a case where
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`a coatable transparent
`insulating film having a specific
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`dielectric constant of 4.0 or higher can be formedat a desired
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`film thickness by using the sol-gel alone, the film may be
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`formed by the sol-gel material alone without using an
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`organic polymeras the transparent film constituting the main
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`material.
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`[Metal Impurity]