GB2246880A

GB2246880A - A colour filter and a method of manufacturing the same

Info

Publication number: GB2246880A
Application number: GB9021065A
Authority: GB
Inventors: Sangi-Gi Jeong; Han-Su Park
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1990-08-10
Filing date: 1990-09-27
Publication date: 1992-02-12
Also published as: DE4030224C1; IT1243051B; GB9021065D0; JPH0493801A; IT9021590A0; KR920004861A; IT9021590A1

Description

i 1 - 1 A COLOUR FILTER AND A METHOD OF MANUFACTURING THE SAME The present

invention relates to a colour filter and a method of manufacturing the same.

Recently, as demand for home video cameras has increased, a smaller in size and lighter in weight video camera has been required. In consequence, a pickup device, comprising a conventional pickup tube, has been substituted with a solid state image sensing device. In a charge coupled device or metal oxide semiconductor type solid state image sensing device, in which the high density technology of semiconductor fields is adopted, the tendency of colour conversion is accelerated and the is resolution is rapidly enhanced according to the progress of high density technology in the semiconductor field.

A colour solid state image sensing device has been embodied by providing a colour filter on a photocell array region in the form of a matrix. The colour filter has at least three colour pattern groups, having colour resolution characteristics which differ from one another. In the case of a combination of three primary colours, the colour filter has red, blue and green colour pattern groups and in the case of a combination of complimentary colours, it has cyan, yellow and magenta colour pattern groups. Accordingly, to manufacture a colour filter on a photocell array region of a solid state image sensing device, processes of coating of photosensitive resin, exposure, development, dyeing and providing a colour mixture prevention layer are carried out at least three times. Accordingly, the colour filter has a structure in which a plurality of layers are laminated, and, therefore, the filter becomes relatively thick. In such relatively thick colour filters, the quantity of transmitted light i 2 eventually arriving at the photocell array is decreased, thereby lowering the sensitivity of the solid state image sensing device.

To solve the problem of the decrease of light transmittance due to the thickness of the colour filter, Japanese patent laid-open publication NO. 61 199 659 discloses a technique for enhancing the sensitivity by focusing light onto each photocell after forming the condenser lens array on a surface of the colour filter to be overlapped with the photocell array. However, this system is very complicated in its structure.

A known method of manufacturing a conventional colour filter is shown in Fig. 1A to Fig. 1E.

Referring to Fig. 1A, the reference numeral 1 designates a semiconductor substrate of a solid state image sensing device having prominences and recesses in the upper portion thereof. The semiconductor substrate 1 is a portion of a photocell array region and has photocells la, lb and ic in respective recesses. The photocells are photodiodes formed in the semiconductor substrate 1. In the prominences of the semiconductor substrate 1, an insulating layer and a conductive layer for wiring are formed. on the upper surf ace of the semiconductor substrate in which the prominence and recess portions are formed, a planarizing layer 2 is formed by coating an organic high polymer material, such as a polyimide, and then a protective layer 3 having dyeing resistance is coated for protecting a bonding pad which is not shown. The protective layer 3 prevents the bonding pad from corrosion during the formation of the coloured pattern discussed later.

i i i 1 1 i 1 1 i i i 1 1 i 1 1 - 3 Referring to Fig. 1B, on the surface of the protective layer 3, a photosensitive resin such as a gelatin or casein containing chlorine dichromate is coated and then a first coloured pattern 4 is formed by exposing and developing the predetermined portion of the layer 3 to be left, via a photolithographic process. Thereafter, a colour mixture preventing material such as a polyglicidyl methacrylate is coated on the surface of the resultant structure in which the first coloured pattern 4 is formed.

by the process shown in Fig. 1B, the first colour pattern layer 4 is formed on the protective layer 3 to be disposed above the photocell la.

If the process of Fig. 1B is twice repeated sequentially with respect to photocells lb and 1c, a second coloured pattern layer 6, an intermediate layer 7, a third coloured pattern layer 8 and an intermediate layer 9 are sequentially formed as shown in Fig. 1C and Fig. 1D.

Referring to Fig. 1E, on a surface of resultant structure in which the first, second and third coloured pattern layers 4, 6 and 8, and intermediate layers 5, 7 and 9 are formed by the above processes, a focus controlling layer 10 is formed by coating with such materials as polyglicidyl methacrylate to a predetermined thickness. Thereafter, a transparent resin material such as an acrylic resin is coated on the focus controlling layer 10 and then patterned to be overlapped with the photocells by a photolithographic process and heated at a predetermined temperature to reflow, and then softbaked. Thus, a condenser lens -having a predetermined radius of curvature can be obtained (refer to Japanese Patent laidopen No. 60-60757).

1 I i 1 i 1 1 1 I 1 1 I i 9E a;9Taaeq Tez)-psAqd P 511TPTAOIC1 Aq:OU PUP SUPWI TRDTW@TD Aq GAP go uoT:9a5Tw s;uaAaad sueaw UoT:pUeAead uoT:ea]5Tw GAP eq: 'A-Cqe-4-pns agAe-E P-Fes OE wo-ii BuT,4ea5Tw GAP BuT:pueAead AT-CeT-4ue-4sqns:zogI:IeAe-c eoue:psqns 9AT4Tsuaso-4oTjd p-pgs 1.4ua-4xe awos o:p -4se-a-E.4e "UTInTM PaPTA0:1d BUT9q sueew UOT:ugAead UOT:kel5TW GAP pue lanoToz) peaTsep 9 go uTeaeg4 GAP 9 5UTPnTouT 9E aeAeT eoue4sqns pTes 'anoToo 5uTae:TT9 209 -4aoddns p-pes uo pap-PA0:1d aeAR-E a:Due-:sqns 9AT:P-Psueso,40,qd 9 J:paoddns L.

:f5UTSTadWOD JIG;TT1 6II:P 'a:DTAep 5Ti-psues G5eup 9-4s-4s P-P-Eos R -log anoTOD R PaPTA02d ST GJ9T-I; lUOT;UeAUT 011; JO:06dSE G110 O; 5TJTPaODDY UOT:en;TS P6UOT:T.Iewa-loge aln U0dn eAoadwT C:P WTE am -ano:)o Aiew s-EeTae,4,ew go ssoT pue pejamoT aq A9w AZ)UaT:)-pg:-;6 uo- p:igisdo "SigART 6-4ETPewae-4UT 30 k;TTRanTd R gO UO-P:RW:EO_; aT'4 SUTPnTZ)11-P -79;TT.J InOTOD aT; eJn4Dggnugw o; papsau ale sde:;s sseooad Auew GOUTS JOSTY -4qb-F-E go uo-p-;onpea o.; anp pejamoT sT AITAy;Tsues atn Pue JP6;ROTIdwoo ST JIT600;0qd ain 0; BUTPEaT lined TEDy;do UP JAT5UTPaODDY WhZT O; uIdOT;noqe se XoTil-4 se sawooeq goeiain ean-4ona4s GaT'4119 aln lean.;XTUI anoToD BuT.;ueAead log saaART 9:RTPOW19;UT ealIT1;SROT ':e sen ODTA6p BuTsues 95ewT ale,4s p-p-ros eiql uo pa;unow ano-Coz) Gin 6OUTS lET 5TA 04 VT f5TA UT Ps;Ea:ksrLTTT SY - t, - 0Z 91 OT l - Said support may include a semiconductor substrate. Said support may include a planarizing layer, said photosensitive substance layer being provided directly on said planarizing layer. Preferably, said photosensitive substance layer is arranged to function as a condenser lens. Said photosensitive substance layer may comprise a resin. Preferably, said photosensitive substance layer comprises gelatin or casein as a main component.

Preferably, said dye migration prevention means is arranged to fix dye molecules in said photosensitive substance layer and thereby prevent migration therefrom.

Suitably, a plurality of separate photosensitive substance layers are provided on said support. Said plurality of layers are preferably provided at the same level on said support. Preferably, each photosensitive substance layer includes a dye therein of a desired colour. Suitably, at least three of said separate photosensitive substance layers are provided, each dyed with a different dye selected from red, blue and green. Alternatively, at least three of said separate photosensitive substance layers may be provided, each dyed with a different dye selected from cyan, yellow and magenta.

Thus, where said photosensitive substance layer is arranged to function as a condenser lens, a plurality of such lenses are suitably provided on the support, preferably at the same level thereon and preferably the lenses are substantially exactly the same size and shape and dyed with a desired colour.

The invention extends to a method of manufacturing a colour filter, the method including the steps of:

1 a support; producing a dyeable photosensitive substance layer on dyeing said layer with a dye; and applying a fluidal processing agent to said substance layer so as substantially to prevent said dye migrating from said substance layer.

The method may further include the step of exposing and developing a predetermined patter on the dyeable photosensitive substance layer.

The method may include the step of forming a condenser lens of a predetermined radius of curvature f rom said dyeable photosensitive substance-layer.

Said fluidal processing agent is preferably arranged to surface process the photosensitive substance layer.

Preferably, said fluidal processing agent is a liquid. Preferably, said fluidal processing agent is tannic acid.

Suitably, said support includes a planarizing layer which is formed before said dyeable photosensitive layer is produced, said dyeable photosensitive layer then being produced on said planarizing layer of the support.

Suitably, the planarizing layer is made from a high polymeric material of, for example, a polyimide group, the thickness of the layer being controlled so that, in use, light incident on the filter is focused on a photocell which may be a part of the support.

The invention further extends to a method of manufacturing a colour filter comprising the steps of:

1 1 1 1 1 1 1 coating a photosensitive resin subject to dyeing on a substrate; exposing and developing a predetermined pattern on the photosensitive resin layer formed in the preceding process and leaving the predetermined pattern; reflowing the patterned layer and softbaking the same to form a condenser lens-having a predetermined radius of curvature; dyeing the condenser lens with a predetermined colouring matter; surface processing the condenser lens with a surface processing material to prevent colour mixture in the succeeding processes; and repeating the above-mentioned processes at least twice eventually to form at least three coloured condenser lenses.

Said photosensitive resin may contain gelatin or casein as the main component. Said surface processing material is preferably tannic acid.

Said substrate is preferably a solid image sensing device having a photocell array therein, and said method may further comprise the steps of:

planarizing the surface of said substrate by forming a planarizing layer, prior to coating said first photosensitive resin, in such a manner that an organic high polymer material of polyimide group is coated on the photocell array region of said solid state image sensing device along with controlling the thickness of the layer to allow the incident light to be focused on said photocell.

Each of at least three condenser lenses may be dyed with one of red, blue and green colours. Alternatively, each of at least three condenser lenses may be dyed with one of cyan, yellow and magenta colours.

Specific embodiments of the invention will now be described, by way of example, with reference to the following diagrammatic drawings, in which:

Fig. 2A to Fig 2D show a colour filter and steps in the manufacture thereof.

Fig. 2A illustrates a process for forming a planaiizing layer 2, for mounting a colour filter on a photocell array region of a solid state image sensing device, on the surface of a semiconductor substrate 1 with organic high polymer of polyimide, in such a manner that the thickness of the planarizing layer is adjusted to allow the incident light to be focused onto the photocells la, lb and 1c.

Fig. 2B illustrates the process for forming a condenser lens 12a on the planarizing layer 2. A photosensitive resin containing, as the principal ingredients, gelatin or casein resin, is coated on the surface of the planarizing layer 2, and then exposed and developed to form a predetermined pattern at a position which overlaps with the photocell la. Thereafter, the resultant pattern is processed to reflow and is softbaked, thereby formong a condenser lens 12a having a predetermined radius of curvature.

1 1 1 1 i i 1 1 i i i i 1 1 j 1 1 i J The condenser lens 12a is then dyed with a colouring matter, having predetermined colour resolution characteristics, and surface processed with a surface processing material such as tannic acid. Suitably, the tannic acid is in aqueous solution when applied to the condenser lens 12a. The surface processing is carried out for 1 to 10 minutes at a temperature in the range of 200C to 600C. By surface processing, the condenser lens is prevented from colour mixture in the succeeding dyeing processes.

The colouring matter used to dye the condenser lens 12a may be any kind of dye, but is preferably not an acid dye. A conventional water soluble dye may be of use.

is References to the relation between acrylic resin and dye may be found in U.S. Patent Number 4 580 159.

As regards the aforementioned surface processing, it may be that, after a condenser lens made of gelatin or casein has been dyed, a water insoluble compound is formed on reaction of the gelatin or casein with tannic acid. The water insoluble compound may then serve to fix individual dye molecules and thereby prevent colour migration in subsequent processes.

Referring to Figs. 2C to 2D, a second condenser lens 12b, overlapping with the second photocell ib, and a thipd condenser lens 12c, overlapping with the third photocell ic are formed in turn through similar processes to those described for the first condenser lens 12a.

As described above, the condenser lenses 12a, 12b and 12c are formed directly on the planarizing layer 2 and then dyed and surface processed in the succeeding processes, thereby doing without the coloured pattern layers and the intermediate layers for colour mixture prevention which were essential for the conventional colour filter. Thus, the entire thickness of the colour filter manufactured by the present method may be reduced to 4pm to 5pm.

Since the thickness of the colour filter may be reduced and the construction of layers thereof simplified, light transmittance andsensitivity of the photocell may be improved and materials required may be reduced.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the feacures disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features z 1 1 1 1 1 i 1 i 1 i 1 i i 1 j 1 i 1 i disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

12 -

Claims

1. A colour filter for a solid state image sensing device, the filter comprising:

3. A colour filter according to claim 1 or 2, said support including a planarizing layer, said photosensitive substance layer being provided directly on said planarizing layer.

a support; a photosensitive substance layer provided on said support for filtering- colour, said substance layer including a dye therein of a desired colour; and dye migration prevention means being provided within, at least to some extent, said photosensitive substance layer, for substantially preventing dye migrating from said layer.

2. A colour filter according to claim 1, said support including a semiconductor substra:e.

4. A colour filter according to any of the preceding claims, said photosensitive substance layer being arranged to function as a condenser lens.

5. A colour filter according to any of the preceding claims, wherein said photosensitive substance layer comprises a resin.

6. A colour filter according to any of the preceding claims, wherein said photosensitive substance layer comprises gelatin or casein as a main component.

1 1 i i 1 i i i 1 1 1 i I i W 7. A colour filter according to any of the preceding claims, wherein said dye migration prevention means is arranged to fix dye molecules in said photosensitive substance layer and thereby prevent migration therefrom.

A colour filter according to any of the preceding claims, wherein a plurality of separate photosensitive substance layers are provided on said support.

9. A colour f ilter according to claim 8, wherein said plurality of layers are provided at the same level on said support.

10. A colour filter according to claim 8 or 9, wherein each photosensitive substance layer includes a dye therein of a desired colour.

11. A colour filter according to any oi claims 8 to 10, wherein at least three of said separate photosensitive substance layers are provided, each dyed with a different dye selected from red, blue and green.

12. A colour filter according to any of claims 8 to 10, wherein at least three of said separate photosensitive substance layers are provided, each dyed with a different dye selected from cyan, yellow and magenta.

13. A method of manufacturing a colour filter, the method including the steps of:

producing a dyeable photosensitive substance layer on a support; dyeing said layer with a dye; and applying a fluidal processing agent to said substance layer so as substantially to prevent said dye migrating from said substance layer.

14. A method according to claim 13, the method further including the step of exposing and developing a predetermined pattern on the dyeable photosensitive substance layer.

15. A method according to claim 13 or 14, the method including the step of forming a condenser lens of a predetermined radius of curvature from said dyeable photosensitive substance layer.

16. A method according to any of claims 13 to 15, wherein said fluidal processing agent is arranged to surface process the photosensitive substance layer.

17. A method according to any of the claims 13 to 16, said fluidal processing agent being a liquid.

18. A method according to any of the claims 13 to 17, said fluidal processing agent being tannic acid.

19. A method according to any of the claims 13 to 18, wherein said support includes a planarizing layer which is formed before said dyeable photosensitive layer is produced, said dyeable photosensitive layer then being produced on said planarizing layer of the support.

20. A method of manufacturing a colour filter comprising the steps of:

coating a photosensitive resin subject to dyeing on a substrate; 1 1 i 4 : 1 1 i I i i i 1 1 1 is - is - exposing and developing a predetermined pattern on the photosensitive resin layer formed in the preceding process and leaving the predetermined pattern; reflowing the patterned layer and softbaking the same to form a condenser lens having a predetermined radius of curvature; dyeing the condenser lens with a predetermined colouring matter; surface processing the condenser lens with a surface processing material to prevent colour mixture in the succeeding processes; and repeating the above-mentioned processes at least twice eventually to form at least three coloured condenser lenses.

21. A method as claimed in claim 20, wherein said photosensitive resin contains gelatin or casein as the main component.

22. A method as claimed in claim 20 or 21, wherein said surface processing material is tannic acid.

23. A method as claimed in any of claims 20 to 22, wherein said substrate is a solid image sensing device having a photocell array therein, and said method further comprises the steps of:

planarizing the surface of said substrate by forming a planarizing layer, prior to coating said first photosensitive resin, in such a manner that an organic high polymer material of polyimide group is coated on the -photocell array region of said solid state image sensing device along with controlling the thickness of the layer to allow the incident light to be focused on said photocell.

24. A method as claimed in any of claims 20 to 23, wherein each of at least three condenser lenses is dyed with one of red, blue and green colours.

25. A method as claimed in any one of claims 20 to 23, wherein each of at least three condenser lenses is dyed with one of cyan, yellow and magenta colours.

26. A colour filter for a solid state image sensing device substantially as hereinbefore described with reference to Figures 2.

27. A method of manufacturing a colour filter substantially as hereinbefore described with reference to 20 Figures 2.

Published 1992 atlbe Patent Office. Concept House. Cardiff Road. Newport, Gwent NP9 IRH. Further copies may be obtained from Sales Branch, Unit 6. Nine Mile Point, Cwmfelinfach, Cross Keys, Newport. NP1 7HZ. Prlnted by Multiplex techniques lid. St Mary Cray. Kent.

i 1 1 i 1 i i 1 1