JP5659889B2 - Inclined structure and method for manufacturing spectroscopic sensor - Google Patents

Description

  The present invention relates to an inclined structure and a method for manufacturing a spectroscopic sensor.

  In fields such as medicine, agriculture, and the environment, a spectroscopic sensor is used for diagnosing and inspecting an object. For example, in the medical field, a pulse oximeter that measures blood oxygen saturation using light absorption of hemoglobin is used. In the field of agriculture, a sugar content meter that measures the sugar content of fruits using light absorption of sugar is used.

  Patent Document 1 listed below discloses a spectral imaging sensor that limits a transmission wavelength band to a photoelectric conversion element by limiting an incident angle with an optical fiber that optically connects an interference filter and the photoelectric conversion element. ing. However, it is difficult to reduce the size of conventional spectroscopic sensors.

JP-A-6-129908

  For example, in order to produce a small spectroscopic sensor, it is required to form a minute inclined structure. However, in the prior art, it is difficult to manufacture a minute inclined structure.

  The present invention has been made in view of the above technical problems. Some embodiments of the present invention relate to providing a manufacturing method capable of manufacturing a minute inclined structure.

In some embodiments of the present invention, the manufacturing method of the inclined structure includes the step (a) of forming the first layer above the substrate and the step of forming the second layer above the first layer ( b), the step (c) of forming an end face in the direction intersecting the plane of the substrate on the second layer, and the end face of the second layer are etched and simultaneously exposed by etching of the end face of the second layer. And (d) sequentially etching the first layer.
According to this aspect, a minute inclined structure can be easily manufactured by a process having high affinity with a semiconductor process.

In the above aspect, in the step (d), it is desirable that the etching rate of the second layer in the surface direction of the substrate is higher than the etching rate of the first layer.
According to this, it is possible to easily manufacture an inclined structure whose inclination angle is gentler than 45 [deg].

In the above aspect, the step (e) of introducing impurity ions into the second layer between the step (b) and the step (c) or between the step (c) and the step (d) is further performed. It is desirable to include.
According to this, the inclination angle of the inclined structure can be adjusted by adjusting the etching rate according to the impurity concentration of the second layer.

In the above-described aspect, in the step (e), the first region and the second region having different impurity concentrations are formed in the second layer, and the step (d) includes forming the end surface in the first region It is desirable to simultaneously etch the end face in the second region.
According to this, by adjusting the etching rate according to the impurity concentration of the second layer, it is possible to form an inclined structure having a plurality of types of inclination angles by one etching.

In the above-described aspect, the method further includes a step (f) of forming a resist layer above the second layer between the step (b) and the step (c), and the step (c) The end surface is formed by etching a part of the second layer as a mask, and the step (d) etches the end surface of the second layer while protecting the upper surface of the second layer with the resist layer. Is desirable.
According to this, even if the thickness of the second layer is thin, the inclined structure can be manufactured.

In the above-described aspect, the second layer formed in the step (b) has a third region and a fourth region having different thicknesses, and the step (f) It is desirable to form a resist layer above the fourth region, and in the step (d), the end surface in the third region and the end surface in the fourth region are etched simultaneously.
According to this, by adjusting the etching rate according to the thickness of the second layer, it is possible to form an inclined structure having a plurality of types of inclination angles by one etching.

In another aspect of the present invention, in the manufacturing method of the inclined structure, the step (a) of forming the first layer on the first surface of the substrate and the second layer above the first layer are formed. A step (b), a step (c) of forming an end surface in a direction intersecting the first surface of the substrate in the second layer, and a step (d) of etching the end surface of the second layer and the first layer. ) And. In the step (d), the etching rate of the second layer in the surface direction of the substrate is larger than the etching rate of the first layer, and the first surface of the substrate of the first layer after the step (d) The end surfaces in the intersecting direction are inclined with respect to the first surface of the substrate.
According to this aspect, a minute inclined structure can be easily manufactured by a process having high affinity with a semiconductor process.

In another aspect of the present invention, a method for manufacturing a spectroscopic sensor includes a step of forming a light receiving element on a substrate, and an angle limiting filter for limiting an incident direction of light passing toward the light receiving element above the light receiving element. And the step of forming the inclined structure by the above-described method above the angle limiting filter, and the multilayer film is formed above the inclined structure, thereby limiting the wavelength of light that can pass through the angle limiting filter. Forming a spectral filter.
According to this aspect, a small spectroscopic sensor can be manufactured by a process having high affinity with a semiconductor process.

Sectional drawing which shows the manufacturing method of the inclination structure which concerns on 1st Embodiment. Sectional drawing which shows the manufacturing method of the inclination structure which concerns on 1st Embodiment. The top view and sectional drawing which show the state in which the resist layer was formed in 1st Embodiment. Sectional drawing which shows the manufacturing method of the inclination structure which concerns on 2nd Embodiment. Sectional drawing which shows the manufacturing method of the inclination structure which concerns on 2nd Embodiment. Sectional drawing which shows the manufacturing method of the inclination structure which concerns on 3rd Embodiment. Sectional drawing which shows the manufacturing method of the inclination structure which concerns on 3rd Embodiment. Sectional drawing which shows the manufacturing method of the inclination structure which concerns on 4th Embodiment. Sectional drawing which shows the manufacturing method of the inclination structure which concerns on 4th Embodiment. Sectional drawing which shows schematic structure of the spectroscopic sensor using the inclination structure which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this embodiment demonstrated below does not unduly limit the content of this invention described in the claim. Further, not all of the configurations described in the present embodiment are essential as a solution means of the present invention. The same constituent elements are denoted by the same reference numerals, and description thereof is omitted.

<1. First Embodiment>
1 and 2 are cross-sectional views showing a method for manufacturing a tilted structure according to the first embodiment of the present invention. 3A is a plan view showing a state in which a resist layer is formed in the first embodiment, and FIG. 3B is a cross-sectional view taken along the line BB in FIG. 3A. (C) is CC sectional view taken on the line of FIG. 3 (A). Note that FIG. 1F corresponds to an enlarged view of the cross section taken along the line FF in FIG.

<1-1. Lamination>
First, as illustrated in FIG. 1A, a first layer 11 serving as an inclined structure is formed over a substrate 10. As the first layer 11, an insulating material or a conductive material can be used depending on the properties required for the inclined structure. Examples of the insulating material include SiOF, PSG (phospho-silicate glass), BPSG (boro-phospho-silicate glass), SiO ₂ , SiN, and an organic film. Examples of conductive materials include Al, Au, Co, Cr, Cu, Mo, Ni, Pt, Ta, Ti, W, Al—Cu alloy, Al—Si—Cu alloy, Si, WSi ₂ , TiSi ₂ , and CoSi _{2. , NiSi 2, CrSi 2, MoSi} 2, TaSi 2, TaN, TiN , and the like. The thickness of the first layer 11 is set according to the height of the inclined surface required for the inclined structure. In addition, although the case where the 1st layer 11 was directly formed on the board | substrate 10 was demonstrated, not only this but another layer may be pinched | interposed between the board | substrate 10 and the 1st layer 11. FIG.

Next, as illustrated in FIG. 1B, the second layer 12 serving as a sacrificial layer is formed over the first layer 11. As the second layer 12, as in the first layer 11, an insulating material or a conductive material can be used. However, the second layer 12 is preferably made of a material whose etching rate in the surface direction of the substrate 10 is larger than that of the first layer 11. For example, when hydrofluoric acid (HF) diluted 10 times with water is used as the etchant, P-SiO ₂ (silicon oxide formed by plasma enhanced chemical vapor deposition) is used as the first layer 11 and the _second layer 11 is used. SOG (Spin on Glass) can be used as the layer 12. Further, using the P-SiN (silicon nitride formed by plasma-enhanced chemical vapor deposition) as the first layer 11, it is possible to use a P-SiO ₂ as the second layer 12. Further, Th—SiO ₂ (silicon oxide formed by thermal oxidation) can be used as the first layer 11, and P—SiO ₂ can be used as the second layer 12.

  The thickness of the second layer 12 is sufficient if the etching solution acts on the end surface of the second layer 12 between the first layer 11 and a resist layer 13 described later. It can be thinner than the layer 11.

  Next, as shown in FIG. 1F, a resist layer 13 having a predetermined shape to be an etching mask is formed in a predetermined region on the second layer 12. As shown in FIG. 3, the resist layer 13 has an opening 13a so as to cover almost the entire first layer 11 and the second layer 12 and to expose a part of the second layer 12. Yes.

The first layer 11 and the second layer 12 may be formed on the entire surface of the substrate 10 or may be patterned into a predetermined shape as shown in FIG. As shown in FIG. 3, the first layer 11 and the second layer 12 are patterned into a predetermined shape, and the side surfaces thereof are covered with a resist layer 13 or the like. The etching solution can be prevented from entering from the left and right direction of (C).
Even when the first layer 11 and the second layer 12 are formed on the entire surface of the substrate 10, the side surfaces of the first layer 11 and the second layer 12 are covered with a certain layer, so that the etching solution Can be prevented from entering.

<1-2. Etching>
Next, as shown in FIGS. 2G to 2I, wet etching of the second layer 12 and the first layer 11 is performed. At this time, first, as shown in FIG. 2G, etching starts from an exposed portion where the upper surface is not protected by the resist layer 13 of the second layer 12. When the exposed part of the second layer 12 is etched, a part of the first layer 11 (a lower part of the etched part of the second layer 12) and the end face of the second layer 12 are exposed. . Thereafter, the exposed first layer 11 and the end face of the second layer 12 are simultaneously etched.

  At this time, since the etching rate of the second layer 12 in the surface direction of the substrate 10 is higher than the etching rate of the first layer 11, as shown in FIGS. 2H and 2I, the second layer 12 Etching from the 12 end faces progresses quickly. When the end surface of the second layer 12 is etched, the first layer 11 is sequentially exposed, so that the etching of the first layer 11 is sequentially started. Accordingly, the etching of the first layer 11 is sequentially started so as to follow the etching of the end face of the second layer 12.

Here, FIG. 2 (G) shows the progress of etching at the time t = -t _g, FIG. 2 (H) shows the progress of etching at the time t = -t _h, FIG. 2 (I) at time It is assumed that the progress of etching at t = 0 is shown. In FIG. 2G, etching proceeds to a point g located at the boundary between the first layer 11 and the second layer 12, and in FIG. 2H, the first layer 11 and the second layer 12 are processed. It is assumed that the etching has progressed to a point h located at the boundary between and the point O located at the boundary between the first layer 11 and the second layer 12 in FIG.

When the etching rate (etching speed) of the second layer 12 is v ₂ , the etching distance (point g and point) that travels in the second layer 12 from time t = −t _g to time t = 0. the distance between the O) is, _{(v 2} × a _{t g),} at time t = distance etching proceeds in the second layer 12 between the -t _h to the time t = 0 (point h and the point O Is the distance (v ₂ × t _h ).

On the other hand, the etching of the first layer 11 at the point g starts when the etching of the second layer 12 proceeds to the point g, and the etching of the first layer 11 at the point h starts with the second layer until the point h. Start when 12 etching progresses. Therefore, when the etching rate of the first layer 11 and _{v 1,} the etching depth of the first layer 11 to proceed during the period from the time t = -t _g to time t = 0 is, _{(v 1} × _t g) , and the etching depth of the first layer 11 to proceed during the period from the time t = -t _h until time t = 0 is _{(v 1} × _{t h).}

Here, the ratio between (v ₂ × t _g ) and (v ₂ × t _h ) is equal to the ratio between (v ₁ × t _g ) and (v ₁ × t _h ). From this, it can be seen that according to the present embodiment, a flat inclined surface can be formed instead of a curved surface with a constant inclination angle.
When the inclined surface is formed, the substrate 10 is taken out from the etching solution before the entire first layer 11 is etched, and the etching is finished.

<1-3. Removal of resist layer>
Finally, as shown in FIG. 2 (J), the inclined structure of the present embodiment is formed by removing the resist layer 13.

  When the ratio of the etching rate of the second layer 12 to the etching rate of the first layer 11 is sufficiently large, the inclination angle of the inclined structure becomes gradual, and the second angle with respect to the etching rate of the first layer 11 is reduced. As the ratio of the etching rate of the layer 12 decreases, the inclination angle of the inclined structure becomes steep. Thereby, the inclination angle of the inclined structure can be adjusted.

<1-4. Effects of the embodiment>
According to the above manufacturing process, the inclined structure can be manufactured using techniques such as film formation and etching that have high affinity with the semiconductor process. Therefore, it becomes easy to mount the inclined structure and the semiconductor circuit on one chip.
Moreover, according to the above manufacturing process, it is not necessary to create an expensive and easily wearable mold in order to manufacture the inclined structure, and it is not necessary to recreate the mold in order to change the shape of the inclined structure. . In addition, not only materials (resins and the like) that can be produced by a mold, but also various materials can be used to manufacture a fine inclined structure.
Moreover, according to the above manufacturing process, it is not necessary to use a special mask such as a gray scale mask. Further, a necessary inclined surface can be formed at a necessary place in a limited space on the substrate.

<2. Second Embodiment>
4 and 5 are cross-sectional views showing a manufacturing method of the inclined structure according to the second embodiment of the present invention. The second embodiment does not have a resist layer that protects the upper surface of the second layer 12 when the first layer 11 and the second layer 12 are etched to form the inclined structure. This is different from the first embodiment.

<2-1. Lamination>
Similar to the first embodiment, first, as shown in FIG. 4A, the first layer 11 serving as the inclined structure is formed on the substrate 10.

  Next, as illustrated in FIG. 4B, the second layer 12 serving as a sacrificial layer is formed over the first layer 11. The steps up to here are the same as in the first embodiment. However, the thickness of the second layer 12 is the thickness of the second layer 12 while the desired inclined structure is formed in the first layer 11 while etching the end face of the second layer 12. It is desirable that the thickness is such that does not become 0, and the thickness can be greater than that of the first layer 11.

Next, as shown in FIG. 4C, a resist layer 14 having a predetermined shape to be an etching mask is formed in a predetermined region on the second layer 12.
Next, as shown in FIG. 4D, the second layer 12 is patterned into a predetermined shape by performing anisotropic etching (dry etching) of the second layer 12 using the resist layer 14 as a mask. . As a result, a part of the upper surface of the first layer 11 and the end surface of the second layer 12 are exposed.
Next, as shown in FIG. 5E, the resist layer 14 is removed. Thereby, the entire upper surface of the second layer 12 is exposed.

<2-2. Etching>
Next, as shown in FIGS. 5G to 5I, wet etching of the second layer 12 and the first layer 11 is performed. At this time, first, as shown in FIG. 5G, the exposed part of the upper surface of the first layer 11, the end surface of the second layer 12, and the entire upper surface of the second layer 12 are simultaneously etched. The

  At this time, since the etching rate of the second layer 12 in the surface direction of the substrate 10 is larger than the etching rate of the first layer 11, the second layer is formed as shown in FIGS. Etching of the end face of 12 proceeds rapidly, and etching of the first layer 11 proceeds so as to follow this. Thereby, according to this embodiment, it is possible to form a flat inclined surface instead of a curved surface with a constant inclination angle.

In order to prevent the upper surface of the first layer 11 from being etched, the etching in the present embodiment is desirably finished before the thickness of the second layer 12 becomes zero.
About another point, it is the same as that of 1st Embodiment.
Through the above steps, the inclined structure of the present embodiment is formed.

<3. Third Embodiment>
6 and 7 are cross-sectional views illustrating a method for manufacturing an inclined structure according to the third embodiment of the present invention. The third embodiment is different from the first embodiment in that the inclination angle of the inclined structure is adjusted by the thickness of the second layer 12.

<3-1. Lamination>
Similar to the first embodiment, first, as shown in FIG. 6A, a first layer 11 serving as an inclined structure is formed on a substrate 10.

  Next, as illustrated in FIGS. 6B to 6E, the second layer 12 serving as a sacrificial layer is formed over the first layer 11. In the present embodiment, a plurality of regions having different thicknesses may be formed as the second layer 12. For this purpose, for example, as shown in FIG. 6B, after a part of the second layer 12 is thinly formed, as shown in FIG. 6C, a predetermined region on the second layer 12 is formed. Then, a resist layer 14 having a predetermined shape to be an etching mask is formed. Next, as shown in FIG. 6D, the second layer 12 is patterned into a predetermined shape by performing anisotropic etching (dry etching) of the second layer 12 using the resist layer 14 as a mask. . Then, as shown in FIG. 6E, the resist layer 14 is removed, and the remaining part of the second layer 12 is formed. Thus, in FIG. 6D, the thick second layer 12 is formed in a region where a part of the second layer 12 is formed, and the thin second layer 12 is formed in other regions.

  Next, as shown in FIG. 7F, a resist layer 13 having a predetermined shape serving as an etching mask is formed in a predetermined region on the second layer 12 (thick region and thin region).

<3-2. Etching>
Next, as in the first embodiment, wet etching is performed on the second layer 12 and the first layer 11 as shown in FIGS. At this time, the etching rate of the second layer 12 is high in the thick region of the second layer 12 and low in the thin region of the second layer 12. This is considered to be due to the fact that when the second layer 12 has a certain thickness or less, the etchant does not easily enter the end face of the second layer 12 between the first layer 11 and the resist layer 13. .

  According to this, the etching rate of the second layer 12 can be adjusted by the thickness of the second layer 12. Therefore, even when the second layer 12 is formed of one kind of material, inclined structures having different inclination angles are formed on the same substrate at a time by changing the thickness of the second layer 12 for each region. can do.

<3-3. Removal of resist layer>
Finally, as shown in FIG. 7 (J), by removing the resist layer 13, the inclined structure of the present embodiment is formed.
About another point, it is the same as that of 1st Embodiment.

<4. Fourth Embodiment>
8 and 9 are cross-sectional views illustrating a method for manufacturing an inclined structure according to the fourth embodiment of the present invention. The fourth embodiment is different from the first embodiment in that the inclination angle of the inclined structure is adjusted by implanting impurity ions into the second layer 12.

<4-1. Lamination>
As in the first embodiment, first, as shown in FIG. 8A, a first layer 11 that forms an inclined structure is formed on a substrate 10.

  Next, as illustrated in FIGS. 8B to 8E, the second layer 12 serving as a sacrificial layer is formed over the first layer 11. In the present embodiment, a plurality of regions having different impurity concentrations may be formed as the second layer 12. For this purpose, for example, as shown in FIG. 8B, after the second layer 12 is formed, as shown in FIG. 8C, ion implantation is performed in a predetermined region on the second layer 12. A resist layer 15 having a predetermined shape to be a mask is formed. Next, as shown in FIG. 8D, ions such as phosphorus, boron, and arsenic are implanted into the second layer 12 using the resist layer 15 as a mask. Then, as shown in FIG. 8E, the resist layer 15 is removed. As a result, the second layer 12 in which no impurity is implanted (low impurity concentration) is formed in the region where the resist layer 15 is formed in FIG. 8C, and the impurity is implanted in the other regions. A second layer 12 (high impurity concentration) is formed.

  Next, as shown in FIG. 9F, a resist layer 13 having a predetermined shape serving as an etching mask is formed in a predetermined region on the second layer 12 (for example, a region having a low impurity concentration and a region having a high impurity concentration). .

<4-2. Etching>
Next, as in the first embodiment, as shown in FIGS. 9G to 9I, the second layer 12 and the first layer 11 are wet-etched. At this time, the etching rate of the second layer 12 is high in a region with a high impurity concentration and low in a region with a low impurity concentration. This is considered to be because the crystal structure is broken and is easily etched by the implantation of impurities into the second layer 12.

  According to this, the etching rate of the second layer 12 can be adjusted by the presence or absence of impurity implantation or the impurity concentration. Therefore, even when the second layer 12 is formed of one kind of material, an inclined structure having different inclination angles can be formed at a time by changing the impurity concentration of the second layer 12 for each region. .

<4-3. Removal of resist layer>
Finally, as shown in FIG. 9J, the inclined structure of the present embodiment is formed by removing the resist layer 13.
About another point, it is the same as that of 1st Embodiment.

  In the present embodiment, a region having a low impurity concentration and a region having a high impurity concentration are formed in the second layer 12, but the entire second layer 12 is a region having a uniform high impurity concentration. May be. By adjusting the impurity concentration of the second layer 12, the tilt angle of the tilted structure can be adjusted.

  In this embodiment, the resist layer 13 is formed on the second layer 12 and etched after the impurity implantation step. However, the second layer 12 is formed before or after the impurity implantation step. The end surface of the second layer 12 may be formed by patterning, and etching may be performed without forming the resist layer 13 on the second layer 12 as described in the second embodiment.

<5. Spectroscopic sensor>
FIG. 10 is a cross-sectional view illustrating a schematic configuration of a spectroscopic sensor using the inclined structure according to the above-described embodiment. The spectral sensor shown in FIG. 10 includes an optical element unit 50 having a light receiving element, an angle limiting filter unit 60, and a spectral filter unit 70.

  The optical element unit 50 includes a substrate 10 made of a semiconductor such as silicon and a photodiode 51 formed on the substrate 10. Further, a predetermined reverse bias voltage is applied to the photodiode 51 on the substrate 10, a current based on the photovoltaic power generated in the photodiode 51 is detected, and an analog signal corresponding to the magnitude of the current is amplified. An electronic circuit (not shown) for converting into a digital signal is formed.

<5-1. Angle limiting filter section>
The angle limiting filter unit 60 is formed above the substrate 10. In the angle limiting filter unit 60, an optical path wall is formed by the light blocking body 61, and an optical path is formed by a light transmitting body 62 such as silicon oxide surrounded by the optical path wall. The light shield 61 is made of a material that does not substantially transmit light having a wavelength that is to be received by the photodiode 51. The light shield 61 is continuously formed over a plurality of layers in a predetermined pattern, for example, in a lattice shape on the substrate 10, thereby forming an optical path in a direction perpendicular to the surface of the substrate 10.

  The angle limiting filter unit 60 limits the incident angle of light passing through the optical path. That is, when the light incident on the optical path is inclined at a predetermined limit angle or more with respect to the direction of the optical path, the light hits the light shielding body 61, a part is absorbed by the light shielding body 61, and the rest is reflected. The The reflected light is weakened by repeated reflections before passing through the optical path. Therefore, light that can pass through the angle limiting filter unit 60 is substantially limited to light that is incident with an inclination with respect to the optical path that is less than a predetermined limiting angle.

<5-2. Spectral filter section>
The spectral filter unit 70 includes an inclined structure 71 formed on the angle limiting filter unit 60 and a multilayer film 72 formed on the inclined structure 71. The multilayer film 72 is formed by laminating a large number of low refractive index thin films such as silicon oxide and high refractive index thin films such as titanium oxide with a slight inclination with respect to the substrate 10.
The low-refractive index thin film and the high-refractive index thin film each have a predetermined thickness of, for example, submicron order, and are laminated over a total of, for example, about 60 layers, so that the entire multilayer film 72 has a thickness of about 6 μm, for example.

  The inclination angle of the multilayer film 72 with respect to the substrate 10 is set to, for example, 0 [deg] or more and 30 [deg] or less in accordance with the set wavelength of light to be received by the photodiode 51. In order to incline the multilayer film 72 with respect to the substrate 10, an inclined structure 71 having translucency is formed on the angle limiting filter unit 60, and the multilayer film 72 is formed thereon. As the inclined structure 71, an inclined structure manufactured by the above-described manufacturing method can be used.

With the above configuration, the spectral filter unit 70 limits the wavelength of light incident on the angle limiting filter unit 60 within a predetermined limiting angle range.
That is, the incident light incident on the spectral filter unit 70 is partially reflected light and partially transmitted light at the boundary surface between the low refractive index thin film and the high refractive index thin film. Then, a part of the reflected light is reflected again at the boundary surface between the other low refractive index thin film and the high refractive index thin film, and is combined with the above-described transmitted light. At this time, light having a wavelength that matches the optical path length of the reflected light is intensified by the phases of the reflected light and the transmitted light being matched, and light having a wavelength that does not match the optical path length of the reflected light is that of the reflected light and the transmitted light. They do not match in phase and weaken (interfere) each other.

  Here, the optical path length of the reflected light is determined by the inclination angle of the multilayer film 72 with respect to the direction of the incident light. Therefore, when the above-described interference action is repeated in, for example, the multilayer film 72 that covers a total of 60 layers, only light having a specific wavelength is transmitted through the spectral filter unit 70 according to the incident angle of the incident light, and a predetermined emission angle is obtained. The light is emitted from the spectral filter unit 70 (for example, at the same angle as the incident angle to the spectral filter unit 70).

  The angle limiting filter unit 60 allows only light incident on the angle limiting filter unit 60 to pass within a predetermined limiting angle range. Therefore, the wavelength of light passing through the spectral filter unit 70 and the angle limiting filter unit 60 is determined by the inclination angle of the multilayer film 72 with respect to the substrate 10 and the limiting angle range of incident light that the angle limiting filter unit 60 passes. Limited to a range of wavelengths.

  By forming an inclined structure 71 having different inclination angles in advance according to the set wavelength of light to be received by the photodiode 51, the multilayer film 72 sets the light to be received by the photodiode 51. Regardless of the wavelength, the same film thickness can be formed by a common process.

<5-3. Optical element section>
The photodiode 51 included in the optical element unit 50 receives light that has passed through the spectral filter unit 70 and the angle limiting filter unit 60 and generates a photovoltaic force. The photodiode 51 includes an impurity region formed by performing ion implantation or the like on the substrate 10 made of a semiconductor.

  The light that has passed through the spectral filter unit 70 and the angle limiting filter unit 60 is received by the photodiode 51 and a photovoltaic force is generated, thereby generating a current. Light can be detected by detecting this current using an electronic circuit (not shown).

<5-4. Spectral sensor manufacturing method>
Here, a manufacturing method of the spectroscopic sensor will be briefly described. In the spectral sensor, first, the photodiode 51 is formed on the substrate 10, then the angle limiting filter unit 60 is formed on the photodiode 51, and then the spectral filter unit 70 is formed on the angle limiting filter unit 60. Manufactured by.

  According to this embodiment, a spectroscopic sensor can be manufactured consistently by a semiconductor process, and a spectroscopic sensor using a tilted structure having a desired tilt angle can be easily formed.

Here, a transmission type spectroscopic sensor in which incident light passes through the spectral filter unit 70 and reaches the optical element unit 50 has been described. However, reflection in which incident light is reflected by the spectral filter unit 70 and reaches the optical element unit. A type of spectroscopic sensor may be used.
Moreover, although the spectroscopic sensor has been described as the element using the inclined structure, the inclined structure may be used as another element. For example, in order to relay an optical signal having a predetermined wavelength in an optical fiber relay device, it may be used as an optical element such as a prism or a mirror.

  DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 11 ... 1st layer (gradient structure), 12 ... 2nd layer (sacrificial layer), 13 ... Resist layer (mask for wet etching), 13a ... Opening, 14 ... Resist layer (for dry etching) Mask), 15 ... resist layer (ion implantation mask), 50 ... optical element part, 51 ... photodiode, 60 ... angle limiting filter part, 61 ... light-shielding body, 62 ... translucent body, 70 ... spectral filter part, 71 ... Inclined structure, 72 ... Multilayer film.

Claims (7)

Forming a first layer above the substrate (a);
Forming a second layer above the first layer (b);
Forming an end surface in a direction intersecting the surface of the substrate on the second layer (c);
Exposing the upper surface of the second layer (g);
At the same time the end face of the second layer and the upper surface of the second layer and the exposed wet etching, the step of sequentially wet etching the first layer exposed by wet etching of the end surface of the second layer (d )When,
Only including,
In the step (d), the manufacturing method of the inclined structure in which the etching rate of the second layer in the surface direction of the substrate is larger than the etching rate of the first layer . In claim 1,
A step (e) of introducing impurity ions into the second layer between the step (b) and the step (c) or between the step (c) and the step (d); The manufacturing method of the inclination structure containing. In claim 2 ,
In the step (e), a first region and a second region having different impurity concentrations are formed in the second layer,
The step (d) is a method of manufacturing an inclined structure in which an end surface in the first region and an end surface in the second region of the second layer are etched simultaneously. In claims 1 to 3 ,
A step (f) of forming a resist layer above the second layer between the step (b) and the step (c);
The step (c) forms the end face by etching a part of the second layer using the resist layer as a mask,
The step (g) is a method of manufacturing a tilted structure, which is a step of exposing the upper surface of the second layer by removing the resist layer . In claim 4 ,
The second layer formed in the step (b) has a third region and a fourth region having different thicknesses,
The step (f) forms the resist layer above the third region and above the fourth region of the second layer,
The step (d) is a method of manufacturing an inclined structure in which the end surface in the third region and the end surface in the fourth region of the second layer are etched simultaneously. Forming a first layer on the first surface of the substrate (a);
Forming a second layer above the first layer (b);
Forming an end surface in a direction intersecting the first surface of the substrate on the second layer (c);
Exposing the upper surface of the second layer (g);
A step (d) of wet- etching the exposed upper surface of the second layer, an end surface of the second layer, and the first layer;
Including
In the step (d), the etching rate of the second layer in the surface direction of the substrate is larger than the etching rate of the first layer,
An end surface of the first layer after the step (d) in a direction intersecting with the first surface of the substrate is
The manufacturing method of the inclination structure which inclines with respect to the 1st surface of the said board | substrate. Forming a light receiving element on the substrate;
Forming an angle limiting filter for limiting an incident direction of light passing toward the light receiving element above the light receiving element;
A step of forming an inclined structure by the method according to any one of claims 1 to 6 above the angle limiting filter;
Forming a spectral filter that limits the wavelength of light that can pass through the angle limiting filter by forming a multilayer film above the inclined structure; and
A method for producing a spectroscopic sensor comprising:

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