JPH06186417A - Manufacture of black matrix by electroless method - Google Patents

Abstract

PURPOSE: To produce a black matrix by an electroless method between the color filter patterns on the inert plate of a liquid crystal display device. CONSTITUTION: A glass plate 1 is provided with one or plural pieces of silane single layers 3 by using silanes, such as hexamethyl disilasane. These layers are then treated with an aq. Pd sol stabilized by a water-soluble polymer, such as PVA and PVP. Pd nuclei 5 having a catalytic effect are formed by this treatment. Since the Pd nuclei 5 have the extremely high catalytic effect, the starting of elecrtroless nickel plating is possible by using all of electroless nickel plating baths low in reactivity which contain a stabilizer and are available on the market. The need for using a curable coating material contg. a photoinitiator or thermal initiator as an activated layer is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an activating layer containing Pd particles on a glass plate, a color filter is provided on the activating layer according to a pattern, and then electroless nickel plating. A nickel black matrix is produced electrolessly on an inert plate of a liquid crystal display by depositing a nickel layer on the activation layer between the color filters in a bath to form a black matrix. It is about the method.

[0002]

2. Description of the Related Art Liquid crystal display (LCD)
And LC-TV). In LCDs, the liquid crystal material is sandwiched between two parallel glass support plates.
Transparent electrodes, usually composed of a semiconductor metal oxide such as tin-doped indium oxide (ITO), are provided on both sides of the glass support plate facing the liquid crystal material. In the case of a liquid crystal television screen (LC-TV), the first glass support plate is the active plate on which the pixel and combination switch elements, eg diode switches, TFTs.
(Thin film transistor) and MIM switch (metal-insulating film-metal) are provided.

The second glass support plate forms an inactive plate and comprises patterned color filters of blue, green and red, the color filters being arranged opposite the pixels of the active plate. The pixel size is, for example, 5
It is 0 × 70 μm. Color filters are provided by screen printing, offset printing, ink jet printing or conventional lithographic techniques. To improve the contrast between the color filters, a light absorbing grating, a so-called "black matrix" is provided between the color filters. As this grid, a chromium thin film formed by sputtering and having color filter holes etched by lithography can be used.

Electrolessly deposited nickel patterns are an advantageous alternative to the chromium thin films described above, especially for large displays where sputtering and photoresist-based lithography require complex processes. is there. Electroless plating, or chemical plating, is a simple and inexpensive way to plate dielectric substrates such as glass and synthetic resins. For this, electroless plating baths such as copper and nickel baths are used, which contain a plurality of complexed metal ions and reducing agents. The metal ions are reduced to metal by the reducing agent at the catalysing surface.

Frequently, metal Pd nuclei are provided on the surface to be plated so that said surface is catalytic. In the standard method, the substrate to be plated is SnCl 2.
₂ aqueous solution and PdCl ₂ aqueous solution,
Alternatively, by contacting with a colloidal SnPd dispersion, nuclei are formed in advance on the substrate to be plated (called activation). As a result, metal Pd nuclei are formed on the surface to be plated by the electroless method. Then, the activated surface is immersed in an electroless plating bath to plate the surface.

Such a method is described in European Patent Application (EP-
A) Known from No. 392235. According to the patent application
If so, water, polyvinyl alcohol (PVA)
Photoinitiators such as coalescing and ammonium dichromate.
Or use a curable coating mixture consisting of thermal initiators
Then, a cured polymer layer having a thickness of 0.2 μm is provided on the glass plate.
It The coating mixture is also PdCl₂Containing P
dCl₂Is excess SnCl ₂Reduced by the coro
Id-shaped metal Pd is formed, and this metal Pd is electroless plated.
Acts as a catalyst in processing. Colloidal metal Pd
The solution is Sn on Pd particles⁴⁺Is stable because
It

After the polymer layer has been cured by exposure to heat or radiation, blue, green and red color filters are provided in a pattern on the cured polymer layer using any of the techniques described above. Then, the glass plate thus treated is immersed in a super alkaline electroless nickel plating bath consisting of an aqueous solution of nickel sulfate, ammonium hydroxide, sodium hypophosphite and 2 mol / l NaOH. In this method, a metal layer composed of nickel and phosphorus derived from a reducing agent is formed between the color filters. This NiP matrix forms a black matrix. In this way, the color filter acts as a mask for the nickel layer to be deposited.

A disadvantage of this known method is the low level of catalytic activity of the Pd particles formed for the electroless nickel plating method. Metal P adsorbing Sn ⁴⁺ ions
The colloidal metal Pd consisting of d and formed by reducing PdCl ₂ with SnCl ₂ is a good activator for electroless copper plating baths that use strongly reducing formaldehyde as the reducing agent. However, the activation method described above is not suitable for most electroless nickel plating baths.
This is because reducing agents such as hypophosphite used in these plating baths have low reactivity and low pH value. This is due to the use of Sn ⁴⁺ ions for the production of Pd sols.

The above-mentioned Sn ⁴⁺ ions are originally used as a stabilizer in the electroless nickel plating bath and prevent oxidation of the reducing agent. For depositing nickel, ultra-highly reactive nickel baths containing no stabilizer, such as the hypophosphite described in European Patent Application (EP-A) 392235, are used. It is necessary to use an alkaline electroless metal plating bath (pH> 14). However, in the absence of a stabilizer in the electroless nickel plating bath, process control is inadequate, selectivity is inadequate, and the risk of bath instability is There is a danger of nickel forming spontaneously. For this reason, commercially available electroless nickel plating baths contain stabilizers, especially heavy metal ions such as Sn ²⁺ , Sn ⁴⁺ and Pb ²⁺ , and organic sulfur compounds such as thioureum. There is.

Another drawback of the known method is that gas is generated inside the PVA dichromate layer when using a reactive electroless nickel plating bath. As a result, the layer is swollen and separated from the substrate.

[0011]

The object of the present invention is, above all, all the electroless nickel plating available on the market in the production of a nickel black matrix on an inert plate of a liquid crystal display in an electroless manner. It is an object of the present invention to provide a method for producing a black matrix which can use a bath and which eliminates the need to use a curable coating mixture containing a photoinitiator or a thermal initiator as an activation layer.

[0012]

The object of the invention is, in the process described at the outset, that the activation layer is constituted by a silane layer activated by an aqueous Pd sol stabilized with a water-soluble polymer. This is achieved by a method of producing a nickel black matrix by an electroless method which is characterized. In this regard, the aqueous Pd sol means a colloidal dispersion in which Pd is dispersed in water. The method of the present invention produces water-soluble polymer-stabilized Pd particles that are not adsorbed on the surface of glass (eg: SiO ₂ , quartz and fused silica), but produce excellent Pd coatings on materials other than glass. Based on what you can and have found.

Even when a monolayer of another material is deposited to modify the glass surface, the adsorption properties of Pd nuclei can be affected. The glass surface can be modified very well by various silanes, which form chemical bonds with the glass surface. According to the method of the present invention, 2 × 10 ¹⁵
A very high density of Pd nuclei of Pd atoms / cm ² can be obtained, and as a result, not only a reactive super alkaline electroless nickel plating bath containing no stabilizer but also a reaction containing a stabilizer can be obtained. Even in all electroless nickel plating baths available on the market with low properties, electroless plating can be started very well.

The dense Pd nuclei also provide very satisfactory adhesion to the deposited nickel layer. The above-mentioned Pd sol is a reducing agent other than Sn ²⁺ salt, such as H ₃ PO ₂ and dimethylaminoborane, which is a Pd salt such as PdC.
l ₂ , Pd nitrate and Pd acetate can be added to an aqueous solution to produce metal Pd.
The solution also contains a water-soluble polymer that stabilizes the Pd sol. Steric hindrance by polymer chains on Pd particles hinders the flocculation of the particles. If such a polymer does not exist, a stable sol cannot be obtained.

Suitable water-soluble polymers are polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP). When PVA is used, a non-uniformly dispersed sol having a particle size of 2 to 10 nm is produced. When PVP is used, a monodisperse sol having a particle size of 2 nm is produced. This is TEM
(Transmission electron microscope). A 2 nm particle contains about 500 Pd atoms. The molecular weight and polymer concentration are chosen such that one polymer chain per Pd particle is adsorbed on the Pd particle. Average molecular weight about 10,000
PVP (for example, K-15 (trade name) available from Fluka) is preferably used.

The relatively low average molecular weight, when combined with the small particles, produces a high density of Pd nuclei on the substrate, so that electroless plating, ie electroless nickel plating, is well initiated. Pd-PVP sol is Pd-PV
The Pd-PVP sol has a longer life cycle because it is more stable than the A sol. Therefore, it is possible to prepare a concentrated stock solution of Pd-PVP and dilute it, for example, 10 times before use. Another advantage of PVP over PVA is that it reduces foam formation in the nucleating solution.

Many silanes, such as the often used hexamethyldisilazane (HMDS), are suitable for use to modify the glass surface. It is preferred to use water-soluble silanes in order to avoid the use of harmful organic solvents. Suitable silanes are water-soluble aminosilanes having at least one alkoxy group. Such silanes include the following formula: R ³ NH (CH ₂ ) ₃ SiR ¹ ₂ (OR ² ) (In the above formula, R ¹ ═CH ₃ , C ₂ H ₅ , methoxy or ethoxy R ² ═CH ₃ or C ₂ H ₅ R ³ = H, CH ₃ , C ₂ H ₅ or (CH ₂ ) _m NHR
There is a compound represented by ⁴ (provided that m = 1, 2 or 3) R ⁴ = H, CH ₃ or C ₂ H ₅ .

Suitable examples are 3-aminopropyltriethoxysilane ("A1100") and N- (2-aminoethyl) -3-aminopropyltrimethoxysilane ("A1100").
1120 "). An example of a suitable material to use is 3-aminopropyldimethylmethoxysilane. The silane concentration in the water is not critical and is, for example, in the range of 0.1 to 3% by weight. The silane layer can be provided by spin coating on a glass plate or by dipping the glass plate in a silane solution.

The time for which the substrate is immersed in the silane solution is not important for the subsequent Pd adsorption step. One of the alkoxy groups of the silane molecule reacts with the hydroxyl group on the glass surface to form a chemical bond. Of course, it is necessary to sufficiently clean the glass surface before the silane treatment, and it is preferable to perform UV-ozone treatment in the final cleaning step. After washing with water, the glass surface is coated with one or several monolayers of silane. That is, the thickness of the silane layer is set to 1 to 5 nm.

As described above, P adsorbed on the glass surface
The number of d atoms is 2 × 1 when using the method of the present invention.
It reaches 0 ¹⁵ pieces / cm ² . When the Pd-PVA sol is used, the density of Pd atoms is 3 × 10 ¹⁵ atoms / cm ² . These values are obtained by the XRF (X-ray fluorescence) method. Such a surface provides a reliable electroless plating treatment with a very large catalytic action even when an electroless nickel plating bath having low reactivity is used. Glycine (pH = 3.8), succinate (pH = 4.5), pyrophosphate (pH = 10-11) or citrate (pH
= 8-9), all known electroless nickel plating baths can be used.

[0021] Also known plating baths available on the market,
For example, Shipley 65 (trade name) (pH =
4.9), OMI Enplate 426 (trade name) (pH = 6 to 7), Shipley Nipposit (Shiple
y Niposit) 468 (trade name) (pH = 7.3), OM
I Enlyte 512 (trade name) (pH = 4.
6) and 514 (trade name) (pH = 9.0) can also be used. In addition to nickel salts, such plating baths usually always contain a reducing agent, such as hypophosphite or dimethylaminoborane, and also a stabilizer. In addition, the deposited nickel layer contains phosphorus (P) or boron (B) depending on the reducing agent used. It is also suitable to use an electroless nickel-cobalt plating bath. The deposited nickel has a transmittance <1% (wavelength 5%) for use as a black matrix.
(At 00 nm). Layer thickness> 0.1μ
All m deposited nickel layers meet this requirement.

After forming the nickel pattern according to the present invention, an equalizing layer and an ITO layer are sequentially provided.

[0023]

The present invention will now be described by way of example with reference to the drawings. Example 1 A polymer stabilized Pd sol suitable for use in the method of the present invention was prepared as follows. 10 g / l Pd
PdC containing Cl ₂ and 350 ml / l concentrated hydrochloric acid
0.6 ml of the ₁₂ aqueous solution was diluted with 38.4 ml of water. To this solution was added 0.07 ml of a 1 wt% polyvinylpyrrolidone (PVP) aqueous solution. The PVP is Fluk
a) Type K-15 (trade name) obtained from the company,
Its average molecular weight was 10,000. Then, 1 ml of a 0.625 molar H ₃ PO ₂ solution was added while stirring. The generated Pd sol is a monodisperse liquid of 2 nm particles,
This was used as the activation solution.

FIG. 1 shows the processing steps of the method of the present invention.
Shows the cross section of the glass substrate, the silane layer to be provided, and the Pd nucleus. Dimensions 9 x 12 cm, thickness 1 mm
Borosilicate glass plate (FIG. 1A) was used as a substrate. 20 g / l sodium gluconate, 25 g / l sodium hydroxide and 3 g / l Tensagex (Tens
The glass plate 1 was cleaned with an aqueous solution containing agex (trade name) (wetting agent). After washing with demineralized water and drying, the glass plate was placed on a UV-ozone reactor (U manufactured by Samco).
It was placed in V-1) for 5 minutes.

Then, the washed glass plate was washed with 3-aminopropyltriethoxysilane (Petrarc).
h) 0.3 of A0750 (trade name) available from the company
It was immersed in a weight% aqueous solution for 1 minute. By the reaction between the ethoxy group of the silane molecule and the -SiOH group of the glass plate,
A silane layer (FIG. 1A) having a thickness of about 1 to 5 nm was formed on the glass surface. Since the silane used has 3 reactive ethoxy groups, the silane layer formed was composed of a three-dimensional network (polysiloxane). A silane in which two ethoxy groups of the silane are substituted with a methyl group (A0735 (trade name) available from Betrach)
, A monolayer of this silane was formed on the glass surface. This denatured glass plate is washed with demineralized water,
Dried.

Then, the above-mentioned PVP is used as an activating solution.
The Pd sol solution stabilized in (4) was used, and the test substrate was immersed in this solution for 4 minutes to form Pd nuclei 5 on the silane layer 3 (FIG. 1B). As a result of analyzing the surface using TEM (transmission electron microscope), the Pd nucleus has a diameter of 2n.
It turned out to be m. As a result of analysis by the XRF (X-ray fluorescence) method, it was found that the coverage was 2 × 10 ¹⁵ atoms / cm ² adsorbed atoms. After the activation treatment, the glass plate was washed with demineralized water and dried.

European Patent Application (EP-A) No. 392 mentioned above.
Using the conventional method described in U.S. Pat. No. 235, color cells 7 (red), 9 (green) and 11 (blue) corresponding to pixels.
A color filter pattern consisting of was provided on the activated surface (FIG. 1C).

Next, the activated glass plate having the above-mentioned color filter pattern was immersed in an electroless nickel plating bath for 3 minutes. This plating bath is 20 per liter of water
g of NiCl ₂ , 16 g of sodium succinate, 10 g
Of sodium hypophosphite, and 2 g of sodium acetate. The pH of this nickel plating bath is HCl
The value was 4.5 and the temperature was kept at 70 ° C. A patterned nickel layer 13 having a layer thickness of 0.2 μm was deposited between the color filters 7, 9 and 11 (FIG. 1D). The nickel pattern formed formed a black matrix. After successive washing with demineralized water and drying, an equalization layer was provided on the color filter pattern and the black matrix, followed by an ITO electrode and an alignment layer (the last three layers not shown). .

Example 2 Example 1 was repeated using Shipley 65 (trade name) (pH = 4.9) as a commercially available electroless nickel plating bath. The plating bath contained hypophosphite as a reducing agent, and a relatively large amount of Pb ²⁺ salt and organic sulfur compound as a stabilizer. 95 ° C
0.2 μm thickness between color filters at bath temperature
Nickel layer was deposited in 1 minute. The surface activated by the method of the present invention is sufficient to electrolessly deposit nickel from a relatively low pH plating bath containing a less reactive hypophosphite which is a stabilizer and a reducing agent. It showed a catalytic effect.

Comparative Example 1 The example described in the above mentioned European patent application (EP-A) 392235 was repeated. A glass plate was coated with a coating mixture consisting of gelatin, ammonium dichromate, hydrochloric acid and water. The mixture also contained colloidal Pd obtained by reducing PdCl ₂ with SnCl ₂ . After curing with UV light, the layer thickness of the coating was 0.2 μm. Then, a color filter pattern was provided by lithography. Instead of the stabilizer-free electroless nickel plating bath described in European Patent Application (EP-A) 392235, a stabilizer-containing electroless plating bath Shipley 65 (trade name) was used. . In this case, nickel deposition did not occur.

The method according to the invention makes it possible to electrolessly produce a black matrix for inert plates used in LCDs. In the method of the present invention, the color filter acts as a mask for electroless nickel plating,
Also, commercially available electroless nickel plating baths containing stabilizers can be used, eliminating the need for curable coating mixtures containing photoinitiators or thermal initiators as the activation layer.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing successive processing steps of the method of the present invention.

[Explanation of symbols]

1 glass plate 3 silane layer (silane single layer) 5 Pd nucleus 7,9,11 color cell (color filter, color filter pattern) 13 patterned nickel layer (black matrix)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Johannes Thomas Srama The Netherlands 5621 Beer Aindow Fenflune Wautzwech 1

Claims (4)

[Claims] 1. An activation layer containing Pd particles is provided on a glass plate, and then a color filter is provided on the activation layer according to a pattern, after which the aforesaid space between the color filters is placed in an electroless nickel plating bath. When the nickel layer is deposited on the inactive plate of the liquid crystal display device by an electroless method by depositing a nickel layer on the activation layer to form a black matrix, the activation layer is a water-soluble layer. Aqueous Pd Stabilized with Water-soluble Polymer
A method for producing a black matrix by an electroless method, characterized by comprising a silane layer activated by a sol. 2. The method according to claim 1, wherein the Pd sol is stabilized with a polymer selected from the group consisting of polyvinyl alcohol and polyvinylpyrrolidone. 3. The method of claim 1, wherein the silane layer is provided by an aqueous aminoalkoxysilane solution. 4. The method of claim 3, wherein the silane is selected from the group consisting of 3-aminopropyltriethoxysilane and N- (2-aminoethyl) -3-aminopropyltrimethoxysilane.