JPS6063537A - Photoworking negative - Google Patents

Abstract

PURPOSE:To prevent a working negative from being damaged by a foreign matter existing between a surface to be worked and a photoworking negative, by constituting so that a worked face side surface of a light non-transmitting part graphic is projected higher than a worked face side surfade of a figure of a light transmitting part. CONSTITUTION:A worked face side surface (chrome surface) of a graphic of a light non-transmitting part 4 of a photoworking negative 3 is projected desirably about 2mum higher than a worked face side surface (glass surface) of a figue of a light transmitting part. In this way, the glass part except the chrome graphic part 4 is etched to a depth of >= several mum, and a distance between the glass surface and the surface of a photosensitive film 2 of the object to be worked 1 is made large, by which even if a foreign matter 7 of about several mum exists, the negative is not damaged, or a degree of the damage is made slight by reducing a contact pressure. In this way, even if photoworking is executed by adopting a contact exposing method or a proximity exposing method which is nearly close to a tight contact, the probability by which the photoworking negative is damaged by a foreign matter is reduced remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an original plate for precision photoprocessing that is less susceptible to damage by foreign objects.

[Background of the invention]

In the so-called photo-processing process, the surface of the workpiece coated with a photosensitive film is exposed to light through a photo-processing original plate on which a desired pattern has been formed.
There are two methods: a method in which the image of the original pattern is projected using a projection lens (proximity exposure method), and a method in which the original pattern image is projected using a projection lens (projection exposure method).

To summarize the advantages and disadvantages of the three types of exposure methods mentioned above, (a) the contact exposure method can most faithfully reproduce the shape of the original image, but on the other hand, the surface of the original plate for ribbing or the workpiece is (b) In the close exposure method, the distance between the original plate and the workpiece is maintained at 1 to several μm, depending on the fineness of the figure, and then exposed. The presence of a foreign object causes a temporary accident in which the foreign object creates a shadow, but the feature is that it does not damage the original plate.On the other hand, the exposed figure may have a penumbra area around it. Because of this, there may be errors in the figure shape,
(C) Projection exposure method, which has the disadvantage that the peripheral part of the residual film after exposure and development is not steep, may be used for completely different purposes such as reduction exposure, but in general, the advantages and disadvantages of close-up exposure method are It becomes even more serious.

Therefore, one of the above methods is selected depending on the properties of the photosensitizer that meet the purpose, the requirements for graphic accuracy, and so on.

The original plates used for such photoprocessing are usually those in which a chrome film is formed on a glass substrate and this film is etched by photoprocessing, or a dry plate in which a silver photographic emulsion is coated on a glass substrate, which is exposed and developed. A photographic image in which silver particles are deposited in a graphic shape is used.

The former is mainly used because the surface of the latter is an organic coating mainly made of gelatin and is therefore extremely susceptible to scratches. but,
Although it may be said that the former is more durable than the latter, it is merely a matter of comparison; the original plate for photo processing is easily damaged by foreign objects, and the same is true for the original plate for chrome.

In currently used chrome master plates, figures are formed by photo-etching a chrome film formed on a glass surface to a thickness of about 200 to 700 nm by sputtering or vacuum evaporation. The chrome film is sometimes made of blackish suboxide on one or both sides in order to lower the light reflectance and reduce the flare phenomenon.

Because of this structure, strictly speaking, in the contact exposure method, the protruding chrome parts of the photoprocessing master should be expressed as being in close contact with the photosensitive coating of the workpiece. The height difference between the chrome part and the glass part is generally smaller than the thickness of foreign matter that exists during the process, so if such foreign matter were to exist, it could cause adhesion or damage not only to the chrome part of the original plate but also to the glass part. This will result in

Depending on the fineness of the figure to be processed and the spectral sensitivity characteristics of the photosensitizer, a light-shielding coating other than chrome may be used, but the circumstances are basically the same.

[Purpose of the invention]

An object of the present invention is to provide an original plate for photoprocessing in which the probability of damage is significantly reduced.

[Summary of the invention]

In order to achieve the above object, in the present invention, the surface of the photoprocessing original plate on the processing surface side (chrome surface) of the light-opaque part figure is made closer to the processing side surface (glass surface) of the light-transmitting part figure. The protrusion is made to protrude at least about 1 μm, preferably about 2 μm or more. In reality, the glass parts other than the chrome graphic parts are etched to a depth of several micrometers or more, and the distance between the glass surface and the photosensitive coating surface of the workpiece is increased, so that in the unlikely event that foreign matter of several micrometers is present, In this case, attempts are made to minimize damage to the original plate by reducing the contact pressure. In this way, even if a foreign object exists between the glass part, that is, the light-transmitting part, of the photoprocessing original plate and the photosensitive coating surface of the workpiece, the original plate will hardly be damaged, and the probability of damage will be greatly reduced. This will result in a decline.

[Embodiments of the invention]

FIG. 1 shows a state in which the original plate for photoprocessing according to the present invention is brought into close contact with a workpiece, where 1 is the base of the workpiece, 2 is the photosensitive coating on the base of the workpiece, and 3 is the photosensitive film according to the present invention. The glass substrate of the original plate for processing, 4 is the light-opaque portion formed in a protruding manner according to the present invention, 5 is the portion of the light-transmissive portion (other than the light-opaque portion) that has been etched away, and 6 is the portion of the light-transmissive portion (other than the light-opaque portion) that has been removed by etching. The remaining portion 7 is a foreign substance.

From this figure, it is clearly seen that even if foreign matter exists between the light-transmitting part of the original and the workpiece, the original will not be damaged.

It depends on the shape of the figure to be exposed, but when the distance between the chrome figures is large, the pressure that brings the glass master into close contact causes the glass master to curve, causing the etched glass surface of the master to come into contact with the workpiece. However, the effect of the present invention may be diminished, so in such a case, as far as circumstances permit when designing the original graphic, unetched glass parts should be left in places as supporting pillars, even if the area is small. is valid.

As a method for producing such a roam master plate, glass etching can be performed directly after chrome etching, and etching with a hydrogen fluoride drug, plasma etching in an atmosphere containing Freon, etc. can be used. Furthermore, in order to more easily etch the glass substrate, it is very effective to form a chrome pattern on a photosensitive glass plate and then perform glass etching to obtain a steeply etched cross section.

Instead of the substrate glass etching described above, a film of a substance that is etched by a chemical that does not etch the substrate glass and chromium is formed on the substrate, and then chromium is deposited and etched, and then the chromium formed by etching is performed. It is also possible to perform etching of the base film using a negative occlusion agent. In this case, there is an advantage that the etched surface can be prevented from becoming rough, which tends to occur when etching a glass substrate with a hydrogen fluoride-based drug.

[As a method for 41u, it is possible to increase the thickness of the chrome figure, but in this case, since the thickness of the opaque part is large, a penumbra is formed on the part of the photoresist that does not face the chrome film. Therefore, there is a drawback that the cross section of the remaining film after development is difficult to become steep. However, even with this method, depending on the gamma characteristics of the photoresist film, it is possible to achieve the effects aimed at by the present invention.

On the other hand, even with an original plate in which the chromium-free areas of the glass substrate are etched, there is some scattering of the light beam passing through the original plate in the etched areas, so it is not possible to obtain exactly the same light intensity distribution as with a conventional original plate. However, the change is negligible.

The greater the amount of etching on the glass surface, the greater the effect, but considering the thickness of foreign substances that are often present in this process and the thickness of the chrome film in the light-opaque area of a normal original plate, it should be at least lIJm or more, preferably 3 μm or more. It is preferable that

Furthermore, as described above, Cr or Cr suboxide is usually used as the light-opaque part, but it is somewhat unstable when etching a glass substrate with a hydrofluoric acid drug. , it is also suitable to use a PT coating.

〔Effect of the invention〕

As explained above, according to the present invention, a photoprocessing original plate for photoprocessing using a contact exposure method or a near-contact exposure method is placed between a workpiece and a photoprocessing original plate. The probability of being damaged by foreign objects that may be present is significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a state in which the original plate for photoprocessing according to the present invention is brought into close contact with a workpiece. 1-Workpiece substrate, 2.--Photosensitive coating on workpiece substrate, 3-Glass substrate of photoprocessing original plate according to the present invention, 4
1. A light-opaque part (chrome part) formed protrudingly according to the present invention, 5. - A portion of the light-transmissive part (other than the light-opaque part) that has been etched away, 6. A remaining part of the etching, 7. -Foreign objects. Figure 1

Claims (1)

[Scope of Claims] 1. In a photoprocessing original plate used for exposure and processing in close contact with the photosensitive surface to be processed or facing it with an extremely small distance, the surface of the pattern of the light-opaque part on the side of the processed surface is transparent. An original plate for photoprocessing 2 characterized by protruding higher than the surface of the processed side of the recessed part figure, the surface of the processed side of the light-opaque part figure is higher than the surface of the processed side of the light-transparent part figure. at least 2μ
The original plate for photoprocessing according to claim 1, which is projected higher than m or more. 3. The original plate for photoprocessing according to claim 1, wherein the light-transmitting portion is formed by etching the surface of the support for the non-light-transmitting portion.