Also, the electro-forming master is immersed again into the electro-forming bath to repeatedly manufacture new fine patterns. Thus, the fine metal pattern of the present invention can be mass produced by repeating the above procedure. Useful for the present invention, the electro- forming master includes a pin part, which is formed of an

insulating material, and preferably, an elastic insulating material. More preferably, the elastic insulating material has releasability. The use of such an insulating material enables a releasing layer which may be additionally formed to the electro-forming master to be unnecessary. In the present invention, the insulating material which simultaneously exhibits releasability, elasticity and insulation is representatively exemplified by silicone.

Therefore, the above insulating material is used, whereby the electro-forming master can be reused.

Background Art In general, a fine metal pattern has been manufactured by means of an etching process acting to corrode a metal, thus having a limitation in accuracy. This is because the etching process causes the metal to corrode in a lateral direction as well as in a downward direction, whereby the etching process has the limitation of processable pitches.

Further, the etching process is disadvantageous in that the corroded amount of the material must be discarded.

However, in the present invention, an electro-forming process is adopted to produce a more accurate metal pattern having finer pitches, instead of the etching process. That is, a metal is allowed to form in only a defined range by a pin part of an electro-forming master used for the electro-

forming process, whereby lateral corrosion of the etching process is not caused. Eventually, fine pitches can be processed. Further, the electro-forming process is characterized in that an electro-forming master is composed of only materials necessary for production of the fine metal pattern, and thus, there is no waste of materials. Also, the electro-forming process enables end products to be simply manufactured, compared to conventional processes. That is, although every product should be conventionally subjected to being exposed to light and etching, the electro-forming process of the present invention does not need such processes, and as well, allows end products to be repeatedly produced by use of an electro-forming master.

Of course, the fine metal pattern has been conventionally manufactured by an electro-forming process.

However, an electro-forming master used for the conventional electro-forming process suffers from a single application.

Otherwise, to prepare a reusable electro-forming master, there is proposed a hard resister to be formed on an electrode base. However, since the hard resister creates stress between an electro-formed product and the resister, when the electro-formed product is released from the resister, such stress prevents the release of the electro- formed product from the resister. That is, the electro- formed product and the resister are mutually interacted, attributed to the stress, upon the removal of the electro-

formed product from the electro-forming master, whereby they may be damaged by each other. Hence, a conventional electro- forming process cannot be repeatedly performed. On the other hand, in the present invention, an elastic pin part is applied to manufacture an electro-forming master, instead of the hard resister, whereby the insulating material has no influence on the electro-formed product upon release.

Accordingly, such an electro-forming master enables the electro-formed product to be easily released therefrom, and also can be reused.

Disclosure of the Invention A fine metal pattern has been conventionally manufactured by means of an etching process-acting to corrode a metal, thus having a limitation in accuracy. This is because the etching process causes the metal to corrode in a lateral direction as well as in a downward direction, whereby the etching process has the limitation of processable pitches. Also, the etching process is disadvantageous in that the corroded amount of the material must be discarded.

However, in the present invention, an electro-forming process is adopted to manufacture a more accurate metal pattern having finer pitches, instead of the etching process. That is, a metal is allowed to form in only a defined range by a pin part of the electro-forming master used for the electro-

forming process, whereby lateral corrosion of the etching process is not caused. Hence, fine pitches can be processed.

Further, the electro-forming process is characterized in that an electro-forming master includes only materials necessary for production of the fine metal pattern, and thus, there is no waste of materials. Also, the electro-forming process enables end products to be simply manufactured, compared to conventional processes. That is, although every product should be conventionally subjected to being exposed to light and etching, the electro-forming process of the present invention does not need such processes and allows end products to be repeatedly produced by use of an electro- forming master. Of course, the fine metal pattern has been conventionally manufactured by an electro-forming process.

However, an electro-forming master used for the conventional electro-forming process suffers from a single application.

Otherwise, to prepare the reusable electro-forming master, there is proposed a hard resister to be formed on an electrode base. However, since the hard resister creates stress between an electro-formed product and the resister, when the electro-formed product is released from the resister, such stress prevents the release of the electro- formed product from the resister. That is, the electro- formed product and the resister are mutually interacted, due to the stress, upon the removal of the electro-formed product from the electro-forming master, whereby they may be damaged

by each other. Hence, a conventional electro-forming process cannot be repeatedly performed. However, in the present invention, an elastic pin part is applied to manufacture an electro-forming master, instead of the hard resister, whereby the insulating material has no influence on the electro- formed product upon release. Accordingly, such an electro- forming master enables the electro-formed product to be easily released therefrom, and can be reused.

Therefore, it is an object of the present invention to alleviate the problems in the related art and to provide an electro-forming master for use in manufacturing a fine metal pattern through an electro-forming process.

Another object of the present invention is to provide a method of manufacturing the electro-forming master.

Still another object of the present invention is to provide a fine metal pattern, manufactured by use of the electro-forming master.

To achieve the above objects, the present invention provides an electro-forming master including an electrode base on which a current-carrying part having a shape identical to that of a fine metal pattern and an insulating part formed of an insulating material are formed. The insulating part, acting as a pin part protruding from a surface of the electrode base, is used to control a shape of a metal to be electro-formed. To increase a height of the pin part, an exposure part of a photosensitive material

is layered. As such, the present invention is characterized in that the exposure part and the insulating part are alternately layered. When the pin part reaches a desired height, the layered exposure part is removed from the electrode base by heat or laser. In such cases, it is noted that only the exposure part should be treated so that the insulating part is not damaged. A depression part, formed by removing the exposure part through heat or laser, allows the surface of the electrode base to be bared. The bared surface of the electrode base comes to be the current- carrying part of the electro-forming master of the present invention, in which the current-carrying part has a shape identical to that of a fine metal pattern. Further, a root part is positioned at a lower portion of the pin part, and is made of an insulating material filled in a recess of the electrode base. The root part is integrally formed with the pin part, and is preferably formed of the same insulating material as the pin part. The recess of the electrode base is formed through an etching process or a mechanical process or a laser process. Moreover, the pin part of the present invention has preferably elasticity, and more preferably, elasticity and releasability. Such an insulating material constituting the pin part is exemplified by silicone capable of exhibiting insulation, releasability and elasticity.

Brief Description of the Drawings The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. 1 is a view schematically showing a fine metal pattern; FIG. 2 is a view sequentially showing a process of preparing a root part of an electro-forming master, according to a first embodiment of the present invention; FIG. 3 is a view sequentially showing a process of layering a first insulating part on an electrode base of the electro-forming master; FIG. 4 is a view sequentially showing a process of layering a second insulating part on the electrode base of the electro-forming master; FIG. 5 is a view sequentially showing a process of layering a third insulating part on the electrode base of the electro-forming master ; FIG. 6 is a view showing an electro-forming process to be performed by immersing the electro-forming master into an electro-forming master; FIG. 7 is a view sequentially showing a process of preparing an electro-forming master, according to a second embodiment of the present invention ; and

FIGS. 8 and 9 are views sequentially showing a process of preparing an electro-forming master, according to a third embodiment of the present invention.

Best Mode for Carrying Out the Invention Based on the present invention, there are provided an electro-forming master for use in repeatedly producing a fine metal pattern through an electro-forming process, and a manufacturing method thereof. Further, a fine metal pattern is provided by use of the electro-forming master.

In the present invention, a finely electro-formed product having various shapes is referred to as a fine metal pattern, which is exemplified by fine current-carrying circuits, lead frames, circuits of chip on film, etc. On a surface of an electrode base of the electro-forming master of the present invention, a current-carrying part and an insulating part are formed. The current-carrying part has the shape identical to that of the fine metal pattern, on which a metal ion is formed in an electro-forming bath.

Further, the electro-forming master of the present invention is classified into two types according to the presence of a recess on the electrode base. As for the electro-forming master having the recess, the recess is formed at an upper portion of the electrode base, and is filled with an insulating material to be a root part. In

addition, a pin part is integrally formed on an upper portion of the root part and protrudes from the surface of the electrode base. In the present invention, the insulating part protruding from the surface of the electrode base is defined as the pin part, and the insulating material under the pin part is defined as the root part that functions to firmly couple the pin part to the electrode base.

The pin part functions to limit the shape of the metal to be electro-formed to a predetermined shape. In addition, the pin part largely affects the shape and the thickness of the fine metal pattern. The fine metal pattern resulting from the electro-forming process has a limited thickness by the height of the pin part. When the fine pattern needs to be formed in a predetermined thickness, the height of the pin part increases to be suitable for the thickness of the fine pattern.

To increase the height of the pin part, a photosensitive material is at least once coated on the electrode base. An exposure part and a non-exposure part are formed to the photosensitive material through an exposing process. The non-exposure part is washed and formed to be a depression part, which is then filled with the insulating material. In the present invention, the formation of the exposure part and the filling of the insulating material are alternately performed. That is, a

first insulating material is filled in a depression part to be flush with a first exposure part, after which a second exposure part is further formed, and subsequently, a second insulating material is further filled in proportion to the height of the second exposure part. When the insulating material reaches a desired height, the exposure part is removed from the electrode base and only the insulating material remains on the electrode base. As such, the remaining insulating material comes to be the pin part.

The present invention is characterized in that the height of the pin part can increase as necessary.

Conventionally, as for an electro-forming process using a resister, the resister has a limited height, and thus, the thickness of the fine pattern to be manufactured by use of the above resister cannot but be limited. However, in the present invention, since the pin part can have a selectively controllable height, the thickness of the fine pattern can freely increase. Meanwhile, the insulating part of the present invention, which prevents a current from flowing, is preferably formed of an insulating material having elasticity and releasability, in consideration of release of an electro-formed product. The insulating part having elasticity endures against stress between the electro-formed product and the insulating part, and acts to easily release the electro-formed product therefrom upon the releasing process. Thus, the insulating part has

preferably elasticity, and more preferably, insulation, elasticity and releasability, which is exemplified by silicone. Thus, silicone, as an example of the above insulating material, exhibits superior insulation, releasability, and elasticity.

Reference should now be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components.

FIG. 1 is a schematic view showing a fine metal pattern, which is a metal pattern 100 having very fine patterns. Such a metal pattern, which is variously applied in the fields of semiconductors or fine circuits, is produced using a film with a transparent portion and an opaque portion. The film has a variety of patterns by means of the transparent portion and the opaque portion.

In the present invention, the above film is used to prepare a pattered electrode base, which is then employed to manufacture an electro-forming master capable of repeatedly producing the fine metal pattern. The present invention is characterized in that the fine metal pattern can be mass produced by use of the inventive electro-forming master.

FIGS. 2 to 5 are views showing the preparation process of an electro-forming master, according to a first embodiment of the present invention.

FIG. -2 is a view sequentially illustrating the

preparation process of a root part of the electro-forming mater, according to the first embodiment of the present invention. As illustrated in FIG. 2, an electrode base 1 is coated with a photosensitive material 2, on which a film having a predetermined pattern is exposed to light, to form an exposure part 3. Subsequently, a non-exposure part is washed and formed to be a depression part, which is then subjected to etching, to prepare a recess 4 in a predetermined depth of an upper portion of the electrode base 1. Like this, the electrode base having the recess 4 is referred to as a recess-formed electrode base. In addition, the recess may be formed by means of a mechanical process or a laser process. After the formation of the recess, the exposure part is washed and removed from the electrode base. Then, an insulating material 6 is filled in the recess 4 of the electrode base, after which it is trimmed to be flush with the electrode base.

Alternatively, the formed recess may be filled with the insulating material in the state of the exposure part not being removed. In such cases, the insulating material is filled to be flush with the exposure part and then is hardened.

Thereafter, only the exposure part is removed from the electrode base while leaving the insulating material on the electrode base, whereby an electro-forming master having a pin part and a root part is obtained. As such,

since the pin part has a height as high as the exposure part, the electro-forming master requiring the low pin part is simply prepared by the above procedure.

FIG. 3 is a view sequentially showing the preparation process of a first insulating part on the electrode base of the electro-forming master. As seen in FIG. 3, after the recess is filled with the insulating material 6, a photosensitive material 7 is coated on the entire upper surface of the electrode base. Then, a first exposure part 8 and a non-exposure part are formed, and the non-exposure part is washed and formed to be a depression part 9. An insulating material is further filled in the depression part to form a first insulating part 10. As such, the used insulating material has adhesion, and is preferably the same as that filled in the recess. When the insulating material is filled in the recess as in FIG. 2, it may be filled after the exposure part is washed, otherwise, it may be filled in the state of the exposure part not being removed. In particular, the insulating material is filled in the presence of the exposure part, therefore directly obtaining the results same as in FIG. 3.

FIG. 4 is a view sequentially showing the preparation process of a second insulating part on the electrode base of the electro-forming master. As seen in FIG. 4, after the insulating material of FIG. 3 is hardened, a photosensitive material 11 is further coated on the entire

surfaces of the first insulating part and the first exposure part of the electrode base. Then, a second exposure part 12 is further formed by use of the above film.

A non-exposure part is washed and formed to be a depression part 13, which is then filled with an insulating material to form a second insulating part 14. As such, the used insulating material is adhesive, and easily adheres to the lower insulating material. The second insulating part is trimmed to be flush with the second exposure part, and then hardened. In the present invention, the adhesive insulating material is exemplified by silicone.

FIG. 5 is a view sequentially showing the preparation process of a third insulating part on the electrode base.

As seen in FIG. 5, after the insulating material of FIG. 4 is hardened, a photosensitive material 13 is further coated on the entire surfaces of the second insulating part and the second exposure part of the electrode base. Then, a third exposure part 14 is further formed by use of the above film, and a non-exposure part is washed and formed to be a depression part 15. Subsequently, an insulating material is further filled in the above depression part to form a third insulating part 16. In this case, the used insulating material has adhesion, and thus, easily adheres to the lower insulating material. By repeating the above procedure, when the layered insulating part reaches a desired height, the stacked exposure part is removed from

the electrode base to obtain a desired pin part. As such, it should be noted that only the exposure parts are removed from the electrode base in the state of the exposure parts and the insulating parts being stacked together on the electrode base. For this, the photosensitive material acting to easily remove the exposure part by heat may be used, or only the exposure part may be selectively removed through laser. Particularly, a color reacting with the laser light is contained in the exposure part, whereby only the exposure part may be selectively removed. Through other different methods, only the exposure part is removed from the electrode base while the insulating part is not damaged. The insulating part 17 which remains on the electrode base 5 after the removal of the exposure part functions as a pin part.

The recess of the electrode base is formed to be a root part, and a pin part is integrally formed on an upper portion of the root part and protrudes from the surface of the electrode base. The shape and height of the pin part functions to determine the shape and thickness of the fine metal pattern, respectively. Although a thick exposure part cannot be formed at a time by use of a typical photosensitive material, the high pin part can be formed through the above process of the present invention, which is regarded to be important.

FIG. 6 is a view showing an electro-forming process

to be performed by immersing the electro-forming master into an electro-forming bath. As seen in FIG. 6, the electrode base 5 is connected with a negative electrode (-) to perform the electro-forming process in the electro- forming bath. Thereby, an ionized metal begins to be formed on the electrode base 5, to produce a fine pattern of thin metal. When the electro-forming process is carried out in the electro-forming bath, a metal ion is formed on the surface of the electrode base bared in the insulating parts 17 over time, hence obtaining a metal layer flush with the insulating part.

FIG. 7 is a view sequentially showing the preparation process of an electro-forming master, according to a second embodiment of the present invention, in which a root part is not formed and only a first insulating part is formed on an electrode base. As apparent from FIG. 7, a photosensitive material 18 is coated on a flat electrode base, after which a film is exposed to light, to prepare an exposure part 19 and a non-exposure part. The non-exposure part is washed and formed to be a depression part 20, which is then filled with an insulating material 21. As such, the insulating material is adhesive, and thus, is easily attached to the electrode base which is positioned at a lower portion thereof. The insulating material is trimmed to be flush with the exposure part and then hardened.

Thereafter, the exposure part 19 is removed from the

electrode base, and only an insulating part 22 remains on the electrode base, which is to be the electro-forming master according to the second embodiment of the present invention.

FIGS. 8 and 9 are views sequentially showing the preparation process of an electro-forming master, according to a third embodiment of the present invention. FIG. 8 illustrates the preparation process of the electro-forming master by forming a third insulating part on an electrode base while a root part is not formed. As illustrated in FIG. 8, a photosensitive material 18 is coated on a flat electrode base, after which a film is exposed to light, to form a first exposure part 19 and a non-exposure part. The non-exposure part is washed and formed to be a depression part 20, which is then filled with an insulating material to obtain a first insulating part 21. As such, the used insulating material is adhesive, and thus, is easily attached to the electrode base which is positioned at a lower portion thereof. The first insulating part 21 is trimmed to be flush with the first exposure part 19 and then hardened. Subsequently, the photosensitive material is further coated on the entire surfaces of the first insulating part and the first exposure part of the electrode base, to which a second exposure part 23 is further formed through the film same as above. A non- exposure part is washed to obtain a depression part 24.

Thereafter, as seen in FIG. 9, an insulating material is further filled in the depression part 24 to form a second insulating part 25. As such, the used insulating material is adhesive, and thus, is easily attached to the lower insulating material. The second insulating part is trimmed and hardened, after which a third insulating part is formed. That is, the photosensitive material is further coated on the entire surfaces of the second insulating part and the second exposure part of the electrode base, to which a third exposure part 26 is further formed through the above film and a non-exposure part is washed to obtain a depression part 27. An insulating material is further filled in the depression part to form a third insulating part 28. In this case, the used insulating material is adhesive, and thus, is easily attached to the lower insulating material. By repeating the above procedure, the layered insulating part can have a desired height. Finally, the stacked exposure parts 19,23 and 26 are removed from the electrode base to obtain a pin part 29.

In the present invention, the electrode base and the insulating material are made of various materials. For example, the electrode base is made of stainless steel, which has superior durability and functions to easily release a finely patterned electro-formed product of thin metal, such as copper or nickel, from the electro-forming master. Further, the insulating material has elasticity.

Thereby, such an insulating material does not generate stress with the electro-formed product resulting from the electro-forming process, thus easily performing the releasing process. In addition, upon the releasing process, the electro-formed product and the insulating material are not mutually damaged. Therefore, it is preferred that the insulating material is elastic. Moreover, to firmly attach the insulating material to the recess or the electrode base, the insulating material has preferably adhesion. Useful for the present invention, the adhesive insulating material having elasticity is exemplified by silicone. When such a silicone insulating material having elasticity and releasability at the same time is used, it is not damaged upon releasing the electro-formed product of thin metal pattern from the electro-forming master. Also, silicone having high releasability acts to easily separate such an electro-formed product from the electro-forming master.

Consequently, in the present invention, there are provided the electro-forming master manufactured through the above embodiments, the manufacturing method thereof and the fine metal pattern repeatedly producible by use of the electro- forming master.

Industrial Applicability As described above, the present invention provides an

electro-forming master, a method of manufacturing the same, and a fine metal pattern manufactured using the same, characterized in that the fine metal pattern can be repeatedly produced by use of the reusable electro-forming master having a pin part. As for the electro-forming master of the present invention, the pin part formed with an insulating material functions to limit the shape of the metal to be electro-formed. Further, a root part is formed at a lower portion of the pin part so as to securely couple the pin part to the electrode base. When the fine pattern should have a predetermined thickness, the height of the pin part increases to be suitable for the thickness of the fine pattern by layering the insulting material. Moreover, the insulating material has preferably elasticity as well as releasability. When the elastic and releasable insulating material is used to perform the electro-forming process, an electro-formed product can be easily released from the electrode base, and also, the electro-forming master can be reused.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.