Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making electrical device
Reexamination Certificate
2001-05-23
2003-12-09
Huff, Mark F. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making electrical device
C430S311000, C430S313000, C430S323000, C430S199000
Reexamination Certificate
active
06660457
ABSTRACT:
TECHNICAL FIELD
The present invention relates to novel methods of forming a conductive pattern.
BACKGROUND ART
Photolithography is conventionally utilized for forming conductive patterns on, for example, plastic substrates or inorganic substrates, in production processes of wiring boards, display panels, etc.
A known method of forming a conductive pattern comprises, for example, the steps of: applying to a substrate surface a conductive pigment paste prepared by dispersing a conductive pigment such as silver powder in a photosensitive resin, to form a photosensitive conductive layer; irradiating the surface of the conductive layer with an electron beam or ultraviolet light through a photomask; developing the conductive layer; and optionally baking the conductive layer.
The above method, however, has the following problems: the conductive layer is incapable of forming a sharp pattern owing to its insufficient photosensitivity; the photosensitive resin is used in a large quantity and thus generates a great amount of gas when baked, thereby causing environmental problems; and the application of the method is limited because of difficulties in obtaining a thick conductive layer.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a novel method of forming a conductive pattern free from the problems of the prior art.
Another object of the present invention is to provide a novel method of forming a conductive pattern, which is capable of forming a sharp pattern, free from environmental problems, and applicable for a wide variety of purposes.
Other objects and features of the present invention will become apparent from the following description.
The present invention provides a method of forming a conductive pattern, comprising the steps of:
(1) depositing a conductive coating-forming resin layer and an energy beam-sensitive coating layer on a substrate in this order;
(2) irradiating a surface of the energy beam-sensitive coating layer with an active energy beam or heat rays directly or through a mask so as to obtain a desired pattern;
(3) developing the energy beam-sensitive coating layer to form a resist pattern coating from the energy beam-sensitive coating layer; and
(4) removing revealed portions of the conductive coating-forming resin layer by development.
The present invention also provides a method of forming a conductive pattern, comprising the steps of:
(1) depositing a conductive coating-forming resin layer and an energy beam-sensitive coating layer on a substrate in this order;
(2) irradiating a surface of the energy beam-sensitive coating layer with an active energy beam or heat rays directly or through a mask so as to obtain a desired pattern; and
(3′) developing the energy beam-sensitive coating layer and the conductive coating-forming resin layer simultaneously.
The present inventors carried out extensive research to solve the problems of the prior art, and found that the problems can be solved when an energy beam-sensitive coating layer is deposited over the surface of a conductive coating-forming resin layer on a substrate, and the surface of the energy beam-sensitive coating layer is irradiated with an active energy beam or heat rays directly or through a mask for forming a desired relief pattern, followed by sequential or simultaneous development of the energy beam-sensitive coating layer and the conductive coating-forming resin layer. The present invention has been accomplished based on these findings.
Each step of the method of the present invention will be described below in detail.
Step (1)
In the step (1), a conductive coating-forming resin layer and an energy beam-sensitive coating layer are deposited on a substrate in this order.
The substrate may be, for example, an electrically insulating glass plate, a glass-epoxy plate or any of various plastic substrates. Examples of plastic substrates include films and plates of polyethylene terephthalate, polyimide or the like. The conductive coating-forming resin as such can be used as a plastic substrate. Further, the substrate may have a circuit pattern previously formed thereon.
The conductive coating-forming resin layer is an uncured resin layer which will be finally formed into a conductive pattern. The resin layer may be one substantially non-curable with the energy of heat rays or light beam radiated onto the surface of the energy beam-sensitive coating layer, or may be one curable by post-treatment with heat or light.
The resin for use in the conductive coating-forming resin layer may be conductive or non-conductive. When a conductive resin is used as a resin component for a conductive coating layer, the conductive resin layer may be formed from the conductive resin itself. However, the conductive resin may be used in combination with not only a conductive transparent pigment, a conductive color pigment or like conductive material, but also a non-conductive or semi-conductive, transparent or color pigment. On the other hand, when a non-conductive resin is used, the resin is rendered conductive by adding a conductive transparent pigment, a conductive color pigment or like conductive material. The non-conductive resin can be evaporated by, for example, post-heating, to obtain a conductive coating layer made of the remaining conductive pigment or like conductive material.
It is preferred that the coating formed from the conductive coating-forming resin layer has a volume resistivity not greater than 10
9
&OHgr;.cm, in particular 1 &OHgr;.cm to 10
8
&OHgr;.cm.
The conductive coating-forming resin layer preferably has a glass transition temperature higher than the temperature to be employed for development of the resin layer. Stated specifically, in the case where the resin layer is developed using a treating solution, the resin layer has a glass transition temperature that is preferably higher, more preferably at least about 5° C. higher, further more preferably about 10° C. to 200° C. higher, than the temperature of the treating solution. In the case where the resin layer is developed using a powder such as sandblast, the resin layer has a glass transition temperature that is preferably higher, more preferably at least about 5° C. higher, further more preferably about 10° C. to 200° C. higher, than the temperature of the treating atmosphere. If the glass transition temperature is lower than the temperature for development, a high-resolution pattern is difficult to obtain. The glass transition temperature can be determined by DSC (differential scanning calorimetry).
The resin composition constituting the conductive coating-forming resin layer is not limited and may be varied according to the substrate for use in the method of the invention or the product to be obtained by the method. For example, a resin composition is usable which comprises a heat-curable or thermoplastic resin, a photocurable resin or like resin component, and optional component(s) such as a conductive transparent pigment, a conductive color pigment or like conductive material, or a non-conductive transparent pigment, a non-conductive color pigment or like non-conductive material.
Resins usable for forming the conductive coating-forming resin layer include, for example, acrylic resins, polyester resins, alkyd resins, organic silicon resins, epoxy resins, melamine resins, vinyl resins, phenol resins, fluororesins, polyurethane resins, oil-soluble polyimide-modified resins, inorganic silicon resins, and modified resins of at least two of these resins.
When using these resins having the above specified glass transition temperature, the conductive coating-forming resin layer can be removed without reduction of resolution, in the case where the resin layer is subjected to powder treatment such as development by blasting, after pattern formation. In the case where the resin layer is treated with a developer after pattern formation, it is preferable to use, as a conductive coating-forming resin, a resin which has the above specified glass transition temperature and is soluble or dispersible in an acid, an alkali, wat
Imai Genji
Kogure Hideo
Kojima Daisuke
Armstrong Kratz Quintos Hanson & Brooks, LLP
Huff Mark F.
Kansai Paint Co. Ltd.
Sagar Kripa
LandOfFree
Method of forming conductive pattern does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of forming conductive pattern, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of forming conductive pattern will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3161918