Abrading – Abrading process – Utilizing shield
Reexamination Certificate
1998-12-16
2001-08-21
Morgan, Eileen P. (Department: 3723)
Abrading
Abrading process
Utilizing shield
C451S030000, C451S031000, C451S038000
Reexamination Certificate
active
06276992
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a method of forming a fine groove in a surface of a mother substrate, such as a ceramic substrate.
DESCRIPTION OF THE RELATED ART
Conventionally, a chip-type piezoelectric resonator or similar component is formed such that a groove is formed in a surface of a ceramic sealing substrate which is to be bonded on both sides of a piezoelectric substrate. By forming the groove, a space allowing for free and unhindered vibration of the piezoelectric substrate is provided. Such a chip-type piezoelectric resonator is disclosed in Japanese Utility Patent Publication No. 7-49860, for example.
Such a ceramic substrate having a groove is initially formed using a press die etc., to form a green sheet which is later baked or fired.
However, there has been a problem that the dimensional accuracy of the groove is not sufficient, because of the shrinkage of the ceramic substrate which occurs during baking.
To solve this problem, a method of forming a groove via sand blasting has been considered. In such a sand blasting process, the surface of a mother substrate is masked by a protective film at locations where the groove will not be formed and a groove is formed by a sand blasting from above the mother substrate.
In this case, silicone or urethane resin is used for the protective film for sand blasting. However, if the silicone or urethane are printed and hardened directly on the mother substrate, the silicone or urethane resin cannot be peeled off of the mother substrate.
There is also a method of masking using thermoplastic ink that has been attempted. In this case, there is an advantage that the resin can be peeled off of the mother sheet by using a solvent. However, the thermoplastic ink does not have sufficient durability to protect the mother sheet during the sand blasting process, and the thermoplastic ink will be easily removed during the sand blasting process. For this reason, the thermoplastic ink cannot be used as a masking material.
In another related method, a photosensitive film for use in a sand blasting process is disclosed in Japanese Laid-Open Unexamined Patent Publication No. 6-161098. This photosensitive film is formed by laminating a water-soluble-resin layer, a photosensitive resin composition layer which includes urethane oligomer as a main component and a cellulose derivative, and a peeling film, on a flexible film, sequentially. However, in this case, since many complicated processes such as pasting a film on a mother material, pasting a mask pattern, exposing and removing a mask pattern, image development, sand blasting, and film peeling are needed, this method cannot be applied to a manufacturing process for making a small-sized component. Moreover, since sand-blast-resistancy and peelability are contrary characteristics, there are problems with finding a material that satisfies both of these important characteristics.
SUMMARY OF THE INVENTION
To solve the problems described above, preferred embodiments of the present invention provide a method of forming a groove on a surface of a mother material which achieves formation of a fine and accurately formed groove by using two different layers made of a material that has a very high resistance to sand blasting and that has excellent peelability, respectively.
A preferred embodiment of the present invention provides a method of forming a groove in a mother substrate including the steps of forming a first layer on a surface of the mother substrate, the first layer including a chain-polymer material which is soluble in an organic solvent, forming a second layer on the first layer except for a portion where the groove is to be formed, the second layer including a chain-polymer material having very high resistance to sand-blasting, forming the groove by cutting the first layer and the mother substrate at the portion where the groove is to be formed via a blast process in which blasting material is directed onto the mother substrate from above the second layer, and removing the first and second layers from the mother material by dissolving the first layer by applying the organic solvent to the first and second layers.
In the above-described method, the material used for the mother substrate may include one selected from the group consisting of a ceramic substrate, a glass substrate, a printed circuit board, a wafer and a stone. The first layer may preferably be formed of a thermoplastic resin. Further, the second layer may preferably include a thermosetting resin of silicone or urethane.
According to the above-described method, the first layer and the second layer are peeled off and removed from the mother substrate by applying the organic solvent. Therefore, compared with the conventional method in which a photosensitive sheet is used, a fine groove in a mother substrate can be accurately formed with fewer steps and much more economically than prior art methods.
Further, the second layer reliably provides a necessary blast-proof property and the first layer reliably provides a necessary peelability. Therefore, the resistance to sand-blasting and peelability can be reconciled and thereby, a groove forming method having excellent operability is obtained.
As described above, the first layer including a chain-polymer material which has excellent solubility in an organic solvent is formed along the entire surface of a mother substrate. It is very important for the chain-polymer material used to form the first layer have removability (solubility in the organic solvent) and not to have blast-resistancy or resistance to sand-blasting. For example, thermoplastic ink such as etching-resist ink or other suitable ink material is preferably used for the chain-polymer material.
Next, the pattern formation of the second layer including cross-linked polymer material which has a very high blast-resistancy is formed on the first layer except for an area where the groove is to be formed. The pattern formation may be done via a printing method, a photo-etching method, or other methods which are suitable for fine processing. For the second layer, a material which does not dissolve in an organic solvent and has excellent blast-resistancy is used. The material for the second layer preferably includes a thermosetting resin such as silicone or urethane system, and a photosensitive polymer-such as UV resin, etc.
After formation of the first and second layers, a sand blasting process is performed, with sand being blasted onto the first and second layers from above the second layer. Because the portion except for the area where the groove is to be formed is protected by the second layer, only the area where the groove is to be formed where only the first layer and the mother material are present are cut. As a blast process, a water blast as well as a sand blast may be used.
Next, the mother substrate having the first and second layers remaining thereon after the blast process has been completed, is etched by the organic solvent. The first layer dissolves and the second layer separates from the mother substrate easily. Thus, a groove is accurately and easily formed on the mother substrate. As an organic solvent, thinner, acetone, or other suitable material can be used, for example. As a mother material, any material is suitable as long as it is capable of having a groove formed therein via a blast process, such as a ceramic substrate, a glass substrate, a printed circuit board, a wafer, or a stone.
Other features and advantages of the present invention will become apparent from the following description of preferred embodiments of the present invention which refers to the accompanying drawings.
REFERENCES:
patent: 4430416 (1984-02-01), Goto et al.
patent: 5069004 (1991-12-01), Gillenwater
patent: 5629132 (1997-05-01), Suzuki et al.
patent: 5916738 (1999-06-01), Takehana et al.
patent: 5924901 (1999-07-01), Takehana et al.
patent: 6037106 (2000-03-01), Komatsu
Houda Masuyoshi
Wajima Masaya
Keating & Bennett LLP
Morgan Eileen P.
Murata Manufacturing Co. Ltd
LandOfFree
Method of forming a groove in a surface of a mother substrate 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 a groove in a surface of a mother substrate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of forming a groove in a surface of a mother substrate will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2468796