JP3600732B2 - Method for manufacturing dielectric multilayer filter - Google Patents

Description

【００３４】
表１からも分かるように、本発明の支持基板を持たない誘電体多層膜フィルタは、透過損失を比較例１および２と同じにした場合においても、過剰損失が０．５である比較例１および２に対して過剰損失が０．３と優れた効果を示している。また、本発明の誘電体多層膜フィルタは、実際に１５μｍの溝を形成した光導波路に挿入しても破損することはなかった。
【００３５】
【発明の効果】
本発明によれば支持基板を必要としない誘電体多層膜フィルタが実現できるため、従来の基板を用いた誘電体多層膜フィルタと比較して薄型化が可能となり、光導波路等に挿入した際の過剰損失を低減できるという効果がある。
【００３６】
また、この誘電体多層膜フィルタの製造において、基板上の第１層目をポリイミド膜とすることにより、多層構造体形成後、これを容易に剥離することができ、かつ多量の生産も可能となる。
【図面の簡単な説明】
【図１】本発明の誘電体多層膜フィルタの製造方法を工程順に示す断面図である。
【符号の説明】
１ 低屈折率層
２ 高屈折率層
３ 誘電体多層膜フィルタ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a thinned dielectric multilayer filter used in an optical communication system or the like.
[0002]
[Prior art]
In an optical communication system, various optical elements and optical components are used. For example, an optical component is used in which a thin dielectric multilayer filter is inserted into an optical element having a minute gap formed in the optical path. This dielectric multilayer filter is required to be thin in order to reduce excess loss generated when the dielectric multilayer filter is inserted. For example, by setting the minute gap in the optical path to several tens of μm or less (the thickness of the dielectric multilayer filter is less than that), the excess loss can be suppressed to about 0.5 dB.
[0003]
Achieving this thinness in a conventional glass substrate dielectric multilayer filter requires extremely difficult work because the glass substrate is very brittle, and the yield is not good. Therefore, realization of a dielectric multilayer filter which is easy to handle has been desired.
[0004]
Japanese Patent Application Laid-Open No. 4-211203 discloses a dielectric multilayer filter in which a substrate is a fluorinated polyimide film. By using the present invention, it is possible to manufacture a dielectric multilayer filter having a thickness of more than 10 μm with good yield. However, in order to further reduce excess loss, a thinner filter may be required as a dielectric multilayer filter. On the other hand, a high-performance multilayer filter has been required, and in some cases, the required performance cannot be satisfied unless the number of layers is close to 100 layers. As the number of layers increases, the thickness of the dielectric multilayer film increases, and the demand for thinning cannot be satisfied. Thus, a thinner dielectric multilayer filter is desired.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a method of manufacturing a dielectric multilayer filter which is thinner than a conventional dielectric multilayer filter.
[0006]
[Means for Solving the Problems]
The present inventors have conducted intensive studies on the configuration of a dielectric multilayer filter in order to achieve the above-described object, and as a result, have found that the objective can be achieved with a dielectric multilayer filter having a new configuration. Reached.
[0010]
The method for manufacturing a dielectric multilayer filter according to the present invention includes :
(A) forming a low refractive index film by polymerizing a polymer material on a substrate by vacuum vapor deposition;
(B) forming a high refractive index film on the low refractive index film;
(C) a step of alternately repeating the steps (a) and (b) to form a multilayer structure;
And (d), characterized in that it comprises a step of peeling the multilayer structure from the substrate.
[0011]
In the above-described manufacturing method, the polymer material is preferably polyimide.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
In a conventional dielectric multilayer filter, an inorganic material is used for both a low refractive index layer and a high refractive index layer. Therefore, only a dielectric multilayer filter is very brittle, and a support substrate is required. However, this support substrate merely provides mechanical strength, is not essential as a dielectric multilayer film, and there is no problem in the performance of the filter even without the support substrate.
[0014]
In the present invention, by using a polymer material having mechanical strength for the low refractive index layer, the multilayer film filter can have sufficient mechanical strength without requiring a support substrate. As a result, the thickness of the dielectric multilayer filter can be reduced.
[0015]
The method for manufacturing the dielectric multilayer filter of the present invention is shown in FIG. 1 and outlined below.
[0016]
FIG. 1 is a diagram showing a method of manufacturing a dielectric multilayer filter 3 according to the present invention in the order of steps . FIG. 1A shows a structure in which a low refractive index layer 1 is laminated on a substrate 4, FIG. 1B shows a structure in which a high refractive index layer 2 is laminated next, and FIG. After the steps (a) and (b) are alternately repeated, the substrate 4 is peeled off to form the multilayer filter 3 (when the number of layers is 30). In the multilayer filter 3, the low-refractive-index layers 1 and the high-refractive-index layers 2 formed of a polymer material are alternately laminated.
[0017]
The high refractive index layer of the present invention preferably has a large refractive index, and particularly preferably a material having a refractive index of more than 2.0. Specifically, titanium dioxide, tantalum pentoxide, or the like is suitable. As the low refractive index layer, various polymer materials can be used, but polymer materials usually used for optics, such as polymethyl methacrylate, polycarbonate, silicone resin, and epoxy resin, are preferable.
[0018]
Considering the manufacturing process of the high refractive index layer and the use of the dielectric multilayer filter for various optical components and optical devices, heat resistance becomes very important. Therefore, polyimide having excellent heat resistance is more preferable. Among the polyimides, a fluorinated polyimide having excellent light transmittance is most preferable. The polyimide used in the present invention can be produced, for example, from the following tetracarboxylic acid anhydrides and diamines. However, it is not limited to these.
[0019]
First, the following are mentioned as tetracarboxylic acid. That is,
(Trifluoromethyl) pyromellitic acid,
Di (trifluoromethyl) pyromellitic acid,
Di (heptafluoropropyl) pyromellitic acid,
Pentafluoroethyl pyromellitic acid,
Bis {3,5-di (trifluoromethyl) phenoxy} pyromellitic acid,
2,3,3 ', 4'-biphenyltetracarboxylic acid,
3,3 ', 4,4'-tetracarboxydiphenyl ether,
2,3 ', 3,4'-tetracarboxydiphenyl ether,
3,3 ', 4,4'-benzophenonetetracarboxylic acid,
2,3,6,7-tetracarboxynaphthalene,
1,4,5,7-tetracarboxynaphthalene,
1,4,5,6-tetracarboxynaphthalene,
3,3 ', 4,4'-tetracarboxydiphenylmethane,
3,3 ', 4,4'-tetracarboxydiphenyl sulfone,
2,2-bis (3,4-dicarboxyphenyl) propane,
2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane,
5,5'-bis (trifluoromethyl) -3,3 ', 4,4'-tetracarboxybiphenyl,
2,2 ', 5,5'-tetrakis (trifluoromethyl) -3,3', 4,4'-tetracarboxybiphenyl,
5,5'-bis (trifluoromethyl) -3,3 ', 4,4'-tetracarboxydiphenyl ether,
5,5'-bis (trifluoromethyl) -3,3 ', 4,4'-tetracarboxybenzophenone,
Bis {(trifluoromethyl) dicarboxyphenoxy} benzene,
Bis {(trifluoromethyl) dicarboxyphenoxy} (trifluoromethyl) benzene,
Bis (dicarboxyphenoxy) (trifluoromethyl) benzene,
Bis (dicarboxyphenoxy) bis (trifluoromethyl) benzene,
Bis (dicarboxyphenoxy) tetrakis (trifluoromethyl) benzene,
3,4,9,10-tetracarboxyperylene,
2,2-bis {4- (3,4-dicarboxyphenoxy) phenyl} propane,
Butanetetracarboxylic acid,
Cyclopentanetetracarboxylic acid,
2,2-bis {4- (3,4-dicarboxyphenoxy) phenyl} hexafluoropropane,
Bis {(trifluoromethyl) dicarboxyphenoxy} biphenyl,
Bis {(trifluoromethyl) dicarboxyphenoxy} bis (trifluoromethyl) biphenyl,
Bis (trifluoromethyl) dicarboxyphenoxy diphenyl ether,
Bis (dicarboxyphenoxy) bis (trifluoromethyl) biphenyl,
Bis (3,4-dicarboxyphenyl) dimethylsilane,
1,3-bis (3,4-dicarboxyphenyl) tetramethyldisiloxane,
Difluoropyromellitic acid,
1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene,
1,4-bis (3,4-dicarboxytrifluorophenoxy) octafluorobiphenyl and the like.
[0020]
Next, examples of the diamine include the following.
[0021]
m-phenylenediamine,
2,4-diaminotoluene,
2,4-diaminoxylene,
2,4-diaminodulene,
4- (1H, 1H, 11H-eicosafluoroundecanooxy) -1,3-diaminobenzene,
4- (1H, 1H-perfluoro-1-butanoxy) -1,3-diaminobenzene,
4- (1H, 1H-perfluoro-1-heptanoxy) -1,3-diaminobenzene,
4- (1H, 1H-perfluoro-1-octanoxy) -1,3-diaminobenzene,
4-pentafluorophenoxy-1,3-diaminobenzene,
4- (2,3,5,6-tetrafluorophenoxy) -1,3-diaminobenzene,
4- (4-fluorophenoxy) -1,3-diaminobenzene,
4- (1H, 1H, 2H, 2H-perfluoro-1-hexanoxy) -1,3-diaminobenzene,
4- (1H, 1H, 2H, 2H-perfluoro-1-dodecanoxy) -1,3-diaminobenzene,
p-phenylenediamine,
2,5-diaminotoluene,
2,3,5,6-tetramethyl-p-phenylenediamine,
2,5-diaminobenzotrifluoride,
Bis (trifluoromethyl) phenylenediamine,
Diaminotetra (trifluoromethyl) benzene,
Diamino (pentafluoroethyl) benzene,
2,5-diamino (perfluorohexyl) benzene,
2,5-diamino (perfluorobutyl) benzene,
Benzidine,
2,2'-dimethylbenzidine,
3,3'-dimethylbenzidine,
3,3'-dimethoxybenzidine,
2,2'-dimethoxybenzidine,
3,3 ', 5,5'-tetramethylbenzidine,
3,3'-diacetylbenzidine,
2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl,
Octafluorobenzidine,
3,3'-bis (trifluoromethyl) -4,4'-diaminobiphenyl,
4,4'-diaminodiphenyl ether,
4,4'-diaminodiphenylmethane,
4,4'-diaminodiphenyl sulfone,
2,2-bis (p-aminophenyl) propane,
3,3'-dimethyl-4,4'-diaminodiphenyl ether,
3,3'-dimethyl-4,4'-diaminodiphenylmethane,
1,2-bis (anilino) ethane,
2,2-bis (p-aminophenyl) hexafluoropropane,
1,3-bis (anilino) hexafluoropropane,
1,4-bis (anilino) octafluorobutane,
1,5-bis (anilino) decafluoropentane,
1,7-bis (anilino) tetradecafluoroheptane,
2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether,
3,3'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether,
3,3'-5,5'-tetrakis (trifluoromethyl) -4,4'-diaminophenyl ether,
3,3'-bis (trifluoromethyl) -4,4'-diaminobenzophenone,
4,4 ''-diamino-p-terphenyl,
1,4-bis (p-aminophenyl) benzene,
p-bis (4-amino-2-trifluoromethylphenoxy) benzene,
Bis (aminophenoxy) bis (trifluoromethyl) benzene,
Bis (aminophenoxy) tetrakis (trifluoromethyl) benzene,
4,4 ′ ″-diamino-p-quarterphenyl,
4,4'-bis (p-aminophenoxy) biphenyl,
2,2-bis {4- (p-aminophenoxy) phenyl} propane,
4,4'-bis (3-aminophenoxyphenyl) diphenyl sulfone,
2,2-bis {4- (4-aminophenoxy) phenyl} hexafluoropropane,
2,2-bis {4- (3-aminophenoxy) phenyl} hexafluoropropane,
2,2-bis {4- (2-aminophenoxy) phenyl} hexafluoropropane,
2,2-bis {4- (4-aminophenoxy) -3,5-dimethylphenyl} hexafluoropropane,
2,2-bis {4- (4-aminophenoxy) -3,5-ditrifluoromethylphenyl} hexafluoropropane,
4,4'-bis (4-amino-2-trifluoromethylphenoxy) biphenyl,
4,4'-bis (4-amino-3-trifluoromethylphenoxy) biphenyl,
4,4'-bis (4-amino-2-trifluoromethylphenoxy) diphenyl sulfone,
4,4'-bis (3-amino-5-trifluoromethylphenoxy) diphenyl sulfone,
2,2-bis {4- (4-amino-3-trifluoromethylphenoxy) phenyl} hexafluoropropane,
Bis {(trifluoromethyl) aminophenoxy} biphenyl,
Bis [{(trifluoromethyl) aminophenoxy} phenyl] hexafluoropropane,
Diaminoanthraquinone,
1,5-diaminonaphthalene,
2,6-diaminonaphtan,
Bis [{2- (aminophenoxy) phenyl} hexafluoroisopropyl] benzene,
Bis (2,3,5,6-tetrafluoro-4-aminophenyl) ether,
Bis (2,3,5,6-tetrafluoro-4-aminophenyl) sulfide,
1,3-bis (3-aminopropyl) tetramethyldisiloxane,
1,4-bis (3-aminopropyldimethylsilyl) benzene,
Bis (4-aminophenyl) diethylsilane,
1,3-diaminotetrafluorobenzene,
1,4-diaminotetrafluorobenzene,
4,4'-bis (tetrafluoroaminophenoxy) octafluorobiphenyl and the like.
[0022]
The thickness and number of the high refractive index layer and the low refractive index layer are determined by the specifications of the dielectric multilayer filter to be manufactured, for example, what wavelengths are passed and which wavelengths are cut, and the extinction ratio at that time. It depends on whether or not.
[0023]
The method for manufacturing a dielectric multilayer filter according to the present invention includes a step of alternately stacking high refractive index layers and low refractive index layers made of a polymer material. When a high refractive index layer is formed, for example, when titanium dioxide or tantalum pentoxide is used as a material, various conventional inorganic thin film forming methods such as an ion assisted vapor deposition method and a sputtering method can be used. On the other hand, for forming a low refractive index layer of a polymer material, a method of applying a solution of a polymer to be a material by a method such as spin coating and drying by heating, a vapor deposition polymerization method, and the like can be used. A vapor deposition polymerization method excellent in film thickness controllability is preferred.
[0024]
The following manufacturing apparatus can be used for manufacturing the dielectric multilayer filter of the present invention. That is, the manufacturing apparatus includes independent evaporation sources for the low-refractive-index film material and the high-refractive-index film material in the vacuum chamber, and each of the evaporation sources is located to face the substrate. When a polyimide film is used as the low refractive index layer, the raw material monomers of the polyimide film are separately filled in the evaporation source.
[0025]
The following examples illustrate, but do not limit, the manufacture of the dielectric multilayer filter of the present invention.
[0026]
(Example 1)
This embodiment exemplifies a case where the low refractive index layer of the dielectric multilayer filter is a polyimide film and the high refractive index layer is a titanium dioxide film.
[0027]
First, a dielectric multilayer film was formed on a quartz substrate whose surface was optically polished using the above-described multilayer film forming apparatus. Specifically, titanium dioxide is filled in the evaporation source of the high-refractive-index film material, and 2, (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (hereinafter, referred to as one of the evaporation sources of the low-refractive-index film material). , 6FDA) and the other was filled with 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (hereinafter referred to as TFDB) and then evacuated. Subsequently, the shutters of the evaporation sources of the two low-refractive-index film materials filled with the respective monomers are opened, the shutter is closed after depositing 6FDA and TFDB, and the polymerization and imidization are performed on the substrate, and the polyimide of the first layer is formed. A film was formed. Next, titanium dioxide was evaporated from a titanium dioxide evaporation source to form a titanium dioxide film on the polyimide film. This process was repeated to form a total of 30 dielectric multilayer films. The dielectric multilayer filter has a function of transmitting light having a wavelength of 1.3 μm and not transmitting light having a wavelength of 1.55 μm.
[0028]
Next, a 2 mm-long, 2 mm-wide grid-shaped cut is made in the obtained dielectric multilayer film on the quartz substrate by using a cutter, and this is peeled off from the quartz substrate to obtain a 2 mm-long cut. A dielectric multilayer filter having a width of 2 mm and a thickness of 10 μm was obtained.
[0029]
With respect to the obtained dielectric multilayer filter, the excess loss at a wavelength of 1.3 μm was measured to be 0.1 dB, and the transmission loss at a wavelength of 1.55 μm was measured to be 40 dB. Further, the dielectric multilayer filter was inserted into a 15 μm groove formed in a quartz optical waveguide, an optical component was fixed with an adhesive, and the excess loss generated when the dielectric multilayer filter was inserted was measured. Its value was 0.3 dB. When the dielectric multilayer filter was inserted into the groove of the quartz optical waveguide, no breakage occurred, and the handling was the same as that of the polyimide substrate dielectric multilayer filter. The test results are shown in Table 1 below.
[0030]
(Example 2)
The procedure was performed in the same manner as in Example 1 except that pyromellitic dianhydride (hereinafter, referred to as PMDA) and TFDB were used as the polymer materials for the low refractive index layer. A cut was made in the obtained multilayer filter on the quartz substrate, and this was peeled off from the quartz substrate to obtain a dielectric multilayer filter having a length of 2 mm, a width of 2 mm, and a thickness of 10 μm. The filter was excellent in handleability and could be inserted into the groove of the quartz optical waveguide without breakage. Similarly, the filter characteristics are shown in Table 1 below.
[0031]
(Example 3)
The procedure was performed in the same manner as in Example 1 except that PMDA and TFDB were used as the polymer materials of the low refractive index layer and tantalum pentoxide was used as the inorganic material of the high refractive index layer. A cut was made in the obtained multilayer filter on the quartz substrate, and this was peeled off from the quartz substrate to obtain a dielectric multilayer filter having a length of 2 mm, a width of 2 mm, and a thickness of 10 μm. The filter was excellent in handleability and could be inserted into the groove of the quartz optical waveguide without breakage. Similarly, the filter characteristics are shown in Table 1 below.
[0032]
(Comparative Examples 1-2)
Dielectric multilayer having a total filter thickness of 20 μm in which polyimide (Comparative Example 1) and glass (Comparative Example 2) are used as the supporting substrate, the low refractive index layer is made of silicon dioxide, and the high refractive index layer is made of titanium dioxide. A membrane filter was manufactured in the same manner as in Example 1. Similarly, Table 1 shows the characteristics of the obtained filter.
[0033]
[Table 1]

[0034]
As can be seen from Table 1, the dielectric multilayer filter having no supporting substrate of the present invention has an excess loss of 0.5 even when the transmission loss is the same as that of Comparative Examples 1 and 2. The excess loss is 0.3, which is an excellent effect with respect to and 2. Further, the dielectric multilayer filter of the present invention did not break even when it was actually inserted into an optical waveguide having a groove of 15 μm.
[0035]
【The invention's effect】
According to the present invention, since a dielectric multilayer filter that does not require a supporting substrate can be realized, it is possible to reduce the thickness compared to a dielectric multilayer filter using a conventional substrate, and it is possible to reduce the thickness when inserted into an optical waveguide or the like. There is an effect that excess loss can be reduced.
[0036]
In the production of this dielectric multilayer filter, the first layer on the substrate is made of a polyimide film, so that it can be easily peeled off after the formation of the multilayer structure, and mass production is possible. Become.
[Brief description of the drawings]
FIG. 1 is a sectional view illustrating a method for manufacturing a dielectric multilayer filter according to the present invention in the order of steps.
[Explanation of symbols]
1 low refractive index layer 2 high refractive index layer 3 dielectric multilayer filter

Claims (2)

(A) forming a low refractive index film by polymerizing a polymer material on a substrate by vacuum vapor deposition;
(B) forming a high refractive index film on the low refractive index film;
(C) a step of alternately repeating the steps (a) and (b) to form a multilayer structure;
(D) A method of manufacturing a dielectric multilayer filter, comprising a step of peeling the multilayer structure from a substrate. The method for manufacturing a dielectric multilayer filter according to claim 1, wherein the polymer material is polyimide.

Images