JP5098815B2 - Multilayer optical element manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a multilayer optical element used as an optical filter for optical communication, for example.

  Conventionally, as this type of multilayer optical element, a so-called substrate-less multilayer optical element (a multilayer optical element composed of only a multilayer optical film without a substrate) is known (for example, Patent Document 1, 2).

When manufacturing this substrate-less multilayer optical element, as shown in FIG. 2 (a), an aluminum release film 2 is formed on a glass substrate 1 by vacuum deposition, and then FIG. As shown in b), a multilayer optical film 3 is formed on the release film 2 by a sputtering method. Next, as shown in FIG. 2C, one or more (two in FIG. 2C) dividing grooves 4 are formed in the multilayer optical film 3 and the release film 2 by dicing, so that the multilayer optical film 3 and the release film 2 are formed. The film 3 is cut into a predetermined size. Finally, as shown in FIG. 2 (d), the multilayer optical film 3 is separated from the substrate 1 by immersing the substrate 1, the release film 2 and the multilayer optical film 3 in an aqueous NaOH solution to dissolve the release film 2. . Then, a plurality (three in FIG. 2D) of substrate-less multilayer optical elements 5 are obtained.
JP 2006-171076 A Table 2005/001526

  However, in this case, when the substrate-less multilayer optical element 5 is obtained, the dissolution rate of aluminum, which is the material of the release film 2, is small, and thus a large (wide) substrate-less multilayer optical element 5 is manufactured. In some cases, it takes a lot of time.

In order to eliminate such inconvenience, it is conceivable to substitute a material having a higher dissolution rate than aluminum, but in that case, it is not always easy to find a material having a desired dissolution rate. May cause problems. For example, if WO ₃ is used as the material of the release film 2 instead of aluminum, the dissolution rate increases by an order of magnitude, so that a rapid stress release occurs with the dissolution of the release film 2, and the substrateless multilayer optical element Micro cracks may occur in 5.

In view of such circumstances, production how the multilayer film optical element capable of producing a large substrate-less multilayer film optical element while avoiding the problems such as the occurrence of micro-cracks The purpose is to provide.

  The first multilayer optical element manufacturing method according to the present invention includes a release film forming step for forming a release film (2) on a substrate (1), and a multilayer optical film (3 on the release film). ), And an optical film separation step of dissolving the release film and separating the multilayer optical film from the substrate, the method for producing a multilayer optical element comprising: The film is manufactured as a multilayer optical element having a configuration in which a first release layer (2a) having a predetermined dissolution rate and a second release layer (2b) having a dissolution rate smaller than the first release layer are laminated. It is characterized by the method.

  Here, in order to explain the present invention in an easy-to-understand manner, the description has been made in association with the reference numerals of the drawings representing the embodiments. However, it goes without saying that the present invention is not limited to the embodiments.

  According to the present invention, a large substrate-less multilayer optical element can be manufactured while avoiding problems such as the occurrence of microcracks.

Embodiments of the present invention will be described below.
Embodiment 1 of the Invention

  FIG. 1 is a diagram according to Embodiment 1 of the present invention.

  In the first embodiment, when manufacturing a plurality of substrateless multilayer optical elements, the following procedure is used.

First, in the release film forming step, as shown in FIG. 1A, a release film 2 is formed on a glass substrate 1 by vacuum deposition. At this time, as the release film 2, a layer in which a second release layer 2b having a lower dissolution rate than the first release layer 2a is laminated on the first release layer 2a having a predetermined dissolution rate is employed. Here, the first release layer 2a is made of WO ₃ (tungsten oxide) having a thickness of 20 nm, and the second release layer 2b is made of aluminum having a thickness of 10 nm.

Next, the process proceeds to an optical film forming step, and as shown in FIG. 1B, a multilayer optical film 3 is formed on the release film 2 to a predetermined film thickness (for example, 12 to 30 μm) by a sputtering method. To do. At this time, the multilayer optical film 3 is formed by alternately stacking a high refractive index material (for example, Nb ₂ O ₅ , Ta ₂ O ₅ ) and a low refractive index material (for example, SiO ₂ ).

  Thereafter, the process proceeds to an optical film cutting step, and the multilayer optical film 3 is cut into a predetermined size as shown in FIG. For this purpose, one or more (two in FIG. 1C) dividing grooves 4 are formed in the multilayer optical film 3 and the release film 2 by dicing. At this time, each dividing groove 4 reaches the substrate 1. Then, the multilayer optical film 3 and the release film 2 are cut into a predetermined size.

  Finally, the process proceeds to the optical film separation step, and the multilayer optical film 3 is separated from the substrate 1 as shown in FIG. For this purpose, the substrate 1, the release film 2 and the multilayer optical film 3 are immersed in an aqueous NaOH solution having a predetermined concentration (for example, 3%). Then, since the release film 2 is dissolved in the NaOH aqueous solution, the multilayer optical film 3 is separated from the substrate 1. As a result, a plurality (three in FIG. 1D) of substrate-less multilayer optical elements 5 are obtained.

At this time, the release film 2 is composed of two types of release layers (the first release layer 2a and the second release layer 2b) having different dissolution rates, so that the first release layer 2a and the second release layer 2b By appropriately setting the thickness, the dissolution rate of the entire release film 2 can be arbitrarily adjusted according to the multilayer optical film 3. Therefore, the dissolution rate of the release film 2 can be increased and the size of the substrate-less multilayer optical element 5 can be increased by that amount compared to the case where aluminum alone is used as the material of the release film 2. At the same time, unlike the case of using WO ₃ alone as the material of the release film 2, it is possible to avoid the occurrence of micro cracks in the substrate-less multilayer optical element 5.

  Here, the manufacturing operation of the substrateless multilayer optical element 5 is completed.

  As described above, in the first embodiment, when the substrate-less multilayer optical element 5 is manufactured, the dissolution rate of the release film 2 is increased within a range in which microcracks are not generated in the substrate-less multilayer optical element 5. A large substrate-less multilayer optical element 5 without cracks can be manufactured.

In order to confirm the difference in dissolution rate between aluminum and WO ₃ through experiments, a sample in which a release film 2 made of only aluminum is formed on a substrate 1 and a multilayer optical film 3 is formed thereon, Instead of the release film 2, a sample in which a release layer of only WO ₃ was formed was prepared. The thickness of each release film 2 was 10 nm. After forming the dividing groove 4 in each sample by dicing, it was immersed in an aqueous NaOH solution having a concentration of 3%, and the time required for the substrate 1 and the multilayer optical film 3 to be separated in each sample was examined. As a result, it took 44 hours for aluminum, and 1.5 hours for WO ₃ (that is, about 1/30 of aluminum). From this, it was found that the dissolution rate of WO ₃ was about 30 times faster than the dissolution rate of aluminum.

  In addition, since the multilayer optical film 3 is cut into a predetermined size in the optical film cutting step, the completeness of the substrate-less multilayer film optical element 5 as a product is improved.

Furthermore, in the optical film separation step, the first release layer 2a can be moved away from the multilayer optical film 3 by the second release layer 2b of the release film 2 until the first release layer 2a of the release film 2 is completely dissolved. As a result, even if a residual stress is generated inside the multilayer optical film 3 in the optical film forming step, a situation in which this residual stress is released at a stroke does not occur. It is possible to avoid the occurrence of microcracking in 5.
[Other Embodiments of the Invention]

In the first embodiment described above, the case where WO ₃ is employed as the material of the first release layer 2a of the release film 2 has been described. However, the material of the first separation layer 2a is not necessarily limited to WO _3, may be substituted or combined materials other than WO _3.

  Moreover, in Embodiment 1 mentioned above, the case where aluminum was employ | adopted as a material of the 2nd peeling layer 2b of the peeling film 2 was demonstrated. However, the material of the second release layer 2b is not limited to aluminum, and materials other than aluminum (such as zinc, tin, chrome, and other metals) can be substituted or used together. For example, you may form the 2nd peeling layer 2b using aluminum and zinc together.

  Furthermore, in Embodiment 1 described above, the description has been given of the release film 2 having a two-layer structure in which the first release layer 2a and the second release layer 2b are combined. However, as long as this two-layer structure is included, other release layers are used. It is also possible to add.

Furthermore, in Embodiment 1 described above, the case where NaOH is used as the alkali for dissolving the release film 2 has been described. However, an alkali other than NaOH (for example, KOH, Ca (OH) _2, etc.) may be substituted or used in combination. You can also.

  In the above-described first embodiment, the case where the release film 2 in which the first release layer 2a and the second release layer 2b are stacked is described. However, “mixing” is used instead of this “stacking”. It doesn't matter. That is, it is also possible to use a release film 2 having a mixture in which a first substance having a predetermined dissolution rate and a second substance having a dissolution rate smaller than the first substance are mixed. . Such a mixture can be prepared in various ways. As an example, it is conceivable to form a mixture layer on the substrate by simultaneously performing vacuum deposition using the first substance and the second substance as a deposition source. At this time, the mixing ratio of the first substance and the second substance can be arbitrarily changed by appropriately setting the power for vapor deposition of each substance.

  In the first embodiment described above, the case where the optical film cutting step is provided between the optical film forming step and the optical film separating step has been described. However, it is not necessary to cut the multilayer optical film 3 to a predetermined size. In this case, of course, this optical film cutting step can be omitted.

  The present invention can be widely applied to the production of various multilayer optical elements such as edge filters, B-PON filters, CWDM filters, LX4 filters, and micro optical filters.

BRIEF DESCRIPTION OF THE DRAWINGS It is process drawing which shows the manufacturing method of the board | substrate less multilayer optical element which concerns on Embodiment 1 of this invention, Comprising: (a) is sectional drawing which shows a peeling film forming process, (b) is an optical film forming process. (C) is sectional drawing which shows an optical film cutting process, (d) is sectional drawing which shows an optical film separation process. It is process drawing which illustrates the manufacturing method of the conventional board | substrateless multilayer optical element, (a) is sectional drawing which shows a peeling film film-forming process, (b) is sectional drawing which shows an optical film film-forming process, (c) ) Is a cross-sectional view showing the optical film cutting step, and (d) is a cross-sectional view showing the optical film separation step.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate 2 ... Release film 2a ... 1st release layer 2b ... 2nd release layer 3 ... Multilayer optical film 4 ... Dividing groove 5 ... Substrate-less multilayer film optical element (multilayer film optical element)

Claims (6)

A release film forming step of forming a release film on the substrate;
An optical film forming step of forming a multilayer optical film on the release film;
An optical film separation step of dissolving the release film and separating the multilayer optical film from the substrate,
The multilayer film optical element is characterized in that the release film has a configuration in which a first release layer having a predetermined dissolution rate and a second release layer having a dissolution rate smaller than the first release layer are laminated. Production method.   The method for producing a multilayer optical element according to claim 1, wherein the second release layer is interposed between the multilayer optical film and the first release layer. The material of the first release layer is WO ₃ and
The method for manufacturing a multilayer optical element according to claim 1, wherein the material of the second release layer is aluminum. A release film forming step of forming a release film on the substrate;
An optical film forming step of forming a multilayer optical film on the release film;
An optical film separation step of dissolving the release film and separating the multilayer optical film from the substrate,
The release film includes a mixture in which a first substance having a predetermined dissolution rate and a second substance having a dissolution rate smaller than the first substance are mixed. Production method.   The optical film cutting step of cutting the multilayer optical film into a predetermined size is included between the optical film forming step and the optical film separating step. For producing a multilayer optical element. 6. The method for manufacturing a multilayer optical element according to claim 1, wherein in the optical film separation step, the release film is immersed and dissolved in a NaOH solution .

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