DD253881A1 - METHOD FOR PRODUCING COLOR FILTERS WITH TWO OR MORE LIFT-OFF-STRUCTURED COLOR FLUORES - Google Patents

Abstract

The invention relates to a process for the production of color microfilters based on vapor-deposited dye layers. The object of the invention is the production of color microfilters by combining two or more structured Farbstoffaufdampfschichten to ensure a high Filterqualitaet. According to the invention, the masks are degraded enzymatically during the structuring and the individual dye layers are sealed.

Description

Field of application of the invention

The invention relates to a process for producing colored microfilters by applying two or more structured dye vapor layers. The method is used to produce color filters for a solid-state imaging device. Here, a color filter is usually a filter in which color elements (for example, in the colors cyan, yellow and green) are arranged in mosaic or stripe form.

Characteristic of the known state of the art

The advantages of color filters based on vapor-deposited dye layers over color filters made of dyed polymer reliefs have already been described in the literature (eg DE-OS 3023131). The difficulties in the production of such color filters are mainly in the structuring of the deposited dye layers.

The methods described in the literature are sometimes technically very complicated or only partially applicable. Thus, DE-OS document 3023131 describes a method for structuring by means of a laser beam. This process is technically very complicated. Several documents (eg JP 58-168016, JP 58-9108, JP-79207, JP 59-146005) disclose the teaching to apply to the dye layer to be structured a photoresist layer of various kinds and to use this layer as an etching mask for the dye. This process is technically complicated, since in part a plasma etching step is required. In addition, filter production by this process involves a variety of technological steps, i.a. the removal of the etching mask, which can lead to damage of the underlying dye layer or severely limit the number of usable dyes.

Favorable for structuring the vapor-deposited dye layers is the so-called lift-off technique, in which a resist mask is first formed on the substrate. This mask is steamed with the dye, then the resist mask is removed with a stripper; In this case, the dye located on the mask is also removed so that a negative of the resist pattern remains on the substrate. For this purpose, a special photoresist varnish is used {see JP 58-171006), which, however, must be stripped with alcohols or ketones, ie with organic solvents. This represents a limitation of the dyes used.

Object of the invention

The aim of the invention is therefore to provide a method for structuring dye vapor deposited layers, which contains the least possible number of necessary technological steps, is suitable for a variety of vapor-deposited dyes and guarantees excellent quality of the color filters produced.

Explanation of the essence of the invention

The invention has for its object to provide a process for the production of color filters with lift-off-Farbstoffunterdampfschichten, wherein the mask is removed without that attacks the dye layers.

It has been found that the applied dye layers are not attacked if, according to the invention, the mask material is degraded enzymatically.

To produce the first color microfilter layer, a lift-off mask is first formed on the substrate, wherein a photoresist is a water-soluble organic polymer, such as. Gelatine or casein sensitized by bichromates or bisacids. As a result, in mask making, the unexposed parts can be removed in warm water. Subsequently, the mask over a large area with the dye I, z. As a Cu-phthalocyanine to form blue-green filter elements, steamed in a high vacuum.

In the following, the resist mask must be peeled off so that a negative dye pattern remains on the substrate.

According to the invention this is done in an advantageous manner by the degradation of the gelatin in an enzyme solution at room temperature.

This has several advantages: On the one hand, only the requirement that they are water-insoluble, which is virtually no restriction for vapor-deposited dyes on the dyes. On the other hand, the degradation takes place in only slightly alkaline pH range, so that the dyes are not exposed to strong bases (or acids) during stripping.

Furthermore, the degradation takes place without movement of the substrate, so that the mechanical stress of the dye layers is conceivable low. Following the lift-off process, the substrate is dried and it may, possibly after application of an intermediate layer, the second resist mask are applied.

The intermediate layer can also be applied to the uppermost dye layer. It is achieved by an optically transparent sealing of the individual layers. The second dye layer used are particularly indanthrene dyes for the formation of yellow filter elements. The removal of the resist mask happens again according to the invention. If necessary, the process can be repeated for further dye layers.

embodiment

The invention will be explained below with reference to embodiments.

EXAMPLE 1 2 ml of an aqueous bisazide gelatin solution (70 g / l gelatin, 3.5 g / l of the disodium salt of 4,4'-diazidostilbene-2,2'-disulphonic acid) heated to 35 ° C. are removed by means of a centrifuge (2,000 rpm). min) on a cleaned glass substrate (2500 mm ² ). The sample is dried and then exposed through a chromium stencil with a high-pressure mercury lamp HBO500 at a distance of about 35cm for 20s through the layer side. Then the unexposed parts are removed by washing in 35 ⁰ C warm water. The resulting relief is dried and steamed in a high vacuum (p10 ~ ³ Pa) with Cu phthalocyanine, so that the dye layer is about 100 nm thick. Subsequently, the layer is treated for 5 minutes with an enzyme solution (1 g pancreatic enzyme in 11 dilute ammonia, pH 8.5), so that the resist mask is dissolved together with the dye thereon.

After drying, the entire technology is repeated with the yellow dye Indanthrengelb GK (210 nm thick). Subsequently, as an optically transparent protective layer in a high vacuum (p10 ~ ³ Pa) of silicon dioxide is deposited.

Example 2: First, in analogy to the technology described in Example 1, a blue-green filter layer of indigo (150 nm thick) is formed. Thereafter, an optically transparent intermediate layer (styrene-MSA-butyl half-ester in butanol, 5% strength) is applied.

Subsequently, a yellow filter layer of Indanthrengelb G (120nm) is prepared and the finished filter element with a coating (styrene-MSA-Butylhalbester in butanol, 10%) sealed.

Claims (7)

1. A process for the preparation of color filters with two or more lift-off-structured Farbstoffaufdampfschichten, characterized in that the degradation of the polymeric lift-off mask is enzymatic and one or no optically transparent protective layer sealing of the individual dye layers is performed. 2. The method according to claim 1, characterized in that the enzyme-degradable polymer used as a mask consists of gelatin. 3. The method according to item 1 and 2, characterized in that pancreas is used as the enzyme. 4. The method according to claim 1, characterized in that at least one layer contains a phthalocyanine pigment and at least one further layer contains a yellow anthraquinone dye or a quinacridone dye. 5. The method according to claim 1 and 4, characterized in that as dyes preferably Cu-phthalocyanine / Indanthrengelb GK and Hostaperm E are used. 6. The method according to claim 1, characterized in that the protective layer consists of a polymer. 7. The method and claim 1, characterized in that the protective layer consists of an inorganic material.