JPH02440Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a filter manufacturing mask used in manufacturing an optical filter such as a multilayer interference filter.

[Conventional technology]

When a pyro sensor is used as an infrared detector, a multilayer interference filter is attached to the light receiving surface of the pyro sensor as a filter that transmits only a specific wavelength. Since the pyro sensor is small, this filter must be correspondingly small, about a few mm square.

In order to manufacture such small-chip filters, the conventional method was to manufacture a large-area filter (16 mm or 20 mm in diameter) and then cut it into small chips using a cutting machine.

[The problem that the idea attempts to solve]

However, regardless of the cutting method used, cutting the filter causes the vapor-deposited material on the cut edge to peel off, leading to poor yields and making it unsuitable for mass production.In addition, in terms of performance, the peeled off portion of the filter There are drawbacks that may adversely affect the characteristics.

Therefore, when manufacturing small-chip filters, it is necessary to use a mask that hides the portion of the substrate to be cut so that the vapor deposition material does not deposit on the portion of the substrate to be cut.

By the way, if this mask is too thick, it will cause the deposition material to fly toward the substrate during vacuum deposition.
As shown in FIG. 4, if the direction in which the vapor deposited material flies is in an oblique direction, a shadowed area A will be created near the hole 2 of the mask 1, resulting in a portion of the substrate 4 that is not vapor deposited. There are drawbacks.

On the other hand, as shown in, for example, Japanese Utility Model Application Publication No. 52-32270, it is composed of a thick part (approximately 0.1 mm) and a thin part (approximately 0.05 mm or less), and the overall thickness is reduced. A metal mask with steps has been proposed.

However, the metal mask described in this publication is for semiconductor manufacturing where the substrate is not temperature-controlled to a high temperature (e.g., 200°C or higher), and if this metal mask is used as is for manufacturing the above filter, the following will occur. There is an inconvenience.

In other words, the temperature of the substrate 4 during vacuum evaporation is controlled to a high temperature of 200°C or more, so if such a thin mask is applied to this substrate, the mask itself will bend due to the heat, and the close contact between the substrate and the mask will deteriorate. As a result, the properties become worse and the prescribed vapor deposition cannot be carried out.

The present invention has been made with the above-mentioned considerations in mind, and its purpose is to provide a useful mask for manufacturing filters that simultaneously eliminates the drawbacks of thick masks and the inconveniences of thin masks. It is in.

[Means to solve the problem]

In order to achieve the above object, the filter manufacturing mask according to the present invention is formed so that the thick part of the mask has a thickness of about 0.5 mm and the thin part has a thickness of about 0.2 mm. This was discovered by the present inventor as a result of various experiments.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a sectional view of a mask for manufacturing a filter according to an embodiment of the present invention, and FIG. 2 is a plan view of this mask.

In these figures, a mask 1 is made of a heat-resistant metal plate, and has a large number of small holes 2 formed in an array. This mask 1 is heated to 200℃
It must have an appropriate thickness so that it will not bend even at high temperatures, and is approximately 0.5 mm thick. The size of the holes 2 is appropriately set depending on the size of the filter to be manufactured. In this embodiment, in order to manufacture a filter to be attached to the light-receiving surface of a pyro sensor, the holes 2 are set to about 2 to 3 mm square.

The peripheral edge of each hole 2 is formed thin by providing a step 3. The width and thickness of the part where the step 3 is attached must be thin enough so that even if the vapor deposition material flies from the most diagonal direction, there will be no shaded part A as shown in Figure 4. It is necessary to do so. In this embodiment, the width of the step 3 is 1.0 mm from the edge of the hole 2, and the plate thickness is 0.2 mm. The step 3 can be formed by etching, for example.

To manufacture a filter using the mask 1 having the above configuration, first, as shown in FIG.
are aligned and fixed to the substrate 4. Both can be fixed by applying polyimide adhesive tape to several locations around the periphery.

Once the mask 1 is fixed to the substrate 4, it is fixed to the holder 5 and attached to a predetermined position of the lens dome 6 of the vacuum evaporation apparatus, as shown in FIGS. Then, the high refractive index material and the low refractive index material are alternately ejected from the vapor deposition source 7 for vacuum deposition. In this case, since the mask 1 with holes 2 is fixed to the substrate 4, the deposition substance is deposited only on the substrate 4 exposed through the holes 2 of the mask 1.
Moreover, as mentioned above, the steps 3 are provided around the holes 2 in the mask 1, so that the vapor deposition can be carried out completely on the substrate 4 exposed from the holes 2 without creating a shadow around the holes 2. It will be carried out. For example, Ge is used as the high refractive index material, and SiO, for example, is used as the low refractive index material.

After vacuum evaporation is alternately performed a predetermined number of times as described above, vacuum evaporation is also performed on the back surface of the substrate 4 in the same manner. In this case, the mask 1 is placed on the back side of the substrate 4.
are aligned and fixed so that the deposition material is deposited at the same position on both the front and back surfaces of the substrate 4.

When the vacuum deposition on both sides of the substrate 4 is completed,
Remove the substrate 4 from the holder 5, remove the mask 1 from the substrate 4 as shown in FIG. 3D, and finally,
As shown in FIG. 3E, the substrate 4 is cut along a portion 9 to be cut on which the vapor deposition substance 8 is not deposited. This cutting can be performed along the area where the vapor deposition material 8 is not vapor deposited, so the vapor deposition material 8
If it peels off, the above problems will not occur.

[Effect of idea]

As explained above, the mask for filter manufacturing according to the present invention has a thickness of about 0.5 at the thick part of the mask.
mm, and the thickness of the thin part is approximately 0.2 mm, so even if the deposition material flies from an angle to the substrate during vacuum evaporation, there will be no shadow area. It goes without saying that the material can be completely deposited on the substrate exposed through the hole, and there are no steps other than the periphery of the hole, and the thickness of even the thinnest parts is approximately 0.2 mm.
mm, so even if it is used in contact with a high-temperature-controlled optical filter substrate, it will not warp, and therefore good adhesion with the substrate can be maintained, resulting in quality It is possible to manufacture a multilayer interference filter with high performance.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, FIG. 1 is a side view showing an example of a mask for manufacturing a filter according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is the mask. It is a figure which shows the process of manufacturing a filter using. FIG. 4 is a diagram showing the drawbacks when the mask plate thickness is large. 1...mask, 2...hole, 3...step, 4...
substrate.

Claims (1)

[Scope of utility model registration request] In a filter manufacturing mask that has a large number of holes, has two steps with thin walls around the holes and thick walls in other parts, and is used in contact with a substrate for optical filters that is temperature-controlled at a high temperature. , a mask for filter manufacturing, characterized in that the thick part of the mask is formed to have a thickness of about 0.5 mm, and the thin part of the mask has a thickness of about 0.2 mm.