JP5900873B2 - Additive-added photoresist structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photoresist and a thin film structure that is easily thermally separated from a substrate using the photoresist. A fine fiber or a foaming agent is added to the photoresist as an additive, and a desired planar structure is obtained using photolithography. Alternatively, the present invention provides a fine planar or three-dimensional structure having high strength using a photoresist for forming a three-dimensional structure.

Conventionally, a fine three-dimensional structure formed by a micromachining technique, for example, uses a photolithography technique to form a cavity of a predetermined shape by an anisotropic etching technique or sacrificial layer etching of single crystal silicon (Si). In addition, a bridged structure using an inorganic thin film such as a silicon oxide film, a silicon nitride film, or an SOI layer film, or a thin film floating in the air such as a cantilever or a diaphragm structure has been formed (Patent Document 1). It was used for a thermal infrared sensor using a thin film floating in the air thermally separated from the substrate as an infrared light receiving unit, a flow sensor for forming a thin film heater or a thin film temperature sensor, and the like. However, these inorganic thin films are vulnerable to mechanical shocks and thermal strains, and have the problem of causing cracks. In addition, in order to reduce distortion, the silicon oxide film and the silicon nitride film are often formed by a chemical vapor deposition method (CVD method) or the like. However, since a high temperature (for example, 800 ° C.) is required for fabrication, it is necessary to select a material having a melting point higher than that in order to form the sacrificial layer. Furthermore, the equipment is expensive, and it is difficult to form a thin film floating in the air at a low price. In addition, it is easy to use an SOI substrate to make a thin film that is thermally separated from the substrate using an SOI layer film. However, an SOI substrate is 10 times more expensive than a normal silicon substrate. There was also a problem.

The inventor first formed a thin film having a structure floating in the air, thermally separated from the substrate by a cavity, from a photoresist film, and formed a multi-layered thermopile as a temperature sensor. It was proposed that a flow sensor be formed by forming a thin film heater (Japanese Patent Application No. 2011-44604). However, a photoresist film, which is generally an organic thin film, has high resistance to damage due to mechanical shock, but its bending strength is insufficient, and is not suitable for a self-supporting thin film structure.

In order to perform thermal separation from the substrate, a structure that reduces heat escape to the substrate is required. For this purpose, a thin film is formed on the cavity to reduce the thermal conductance. However, the formation of the cavity has many limiting factors such as the material for the sacrificial layer, the material for the substrate, the etchant, the processing temperature, the material for the thin film, and it has been difficult to set materials and conditions that satisfy all of these. Also, since photolithography is used for the shape of these thin films, there is a method and structure in which the number of steps is small and the desired fine shape is achieved in a simple process, and the substrate is a uniform structure. The body was sought.

Further, there has been a demand for a three-dimensional structure that increases the bending strength of the thin film and reduces the heat conduction from the thin film heater, the infrared light receiving portion, and the like formed on the thin film while being a thin film.

JP 2006-184151 A

The present invention has been made to solve the above-described problems, and is a thin-film structure that is easily formed on a substrate and that can be easily separated into a desired shape, thickness, and dimensions. An object of the present invention is to provide a structure using a material for forming a large structure.

In order to achieve the above object, an additive-containing photoresist structure according to claim 1 of the present invention is a three-dimensional structure having a thin film suspended in the air, which is made of a thermosetting product of an additive-containing photoresist pattern. The photoresist is mixed with an insoluble solid additive, and the additive is a fiber.

Generally, there are a photoresist that is a photosensitive resin and a photoresist that is in a liquid state. For those in liquid form, they are applied to the substrate by spin coating or spray coating, and after drying, light is irradiated onto the desired pattern shape (exposure). After passing through a step of elution to form a pattern (development), it is generally heated and cured. Also, the type that remains where the light irradiated during exposure is not eluted during development is called a negative type photoresist, and the type where the light irradiated during exposure does not elute during development is called a positive type. .

The sheet-like photoresist is also in a liquid state in the initial stage, and when it is in the liquid state, powder or fine fibers can be mixed and mixed so as to be uniform. White powder is originally a transparent substance in visible light, and appears white due to a difference in refractive index from air. Therefore, if a liquid enters between powder or fine fibers, the difference in refractive index is reduced and the film becomes almost transparent.

The additive-containing photoresist structure according to claim 2 of the present invention is a case where the additive-containing photoresist pattern is a remaining portion of the additive-containing photoresist on the substrate .

When the additive-containing photoresist is a negative type or a positive type and is in a liquid state, it is preferably applied to the substrate with a spin coater or the like, and when it is in a sheet form, it is preferably attached to the substrate.

The additive is not necessarily one type, but is a case where a fiber is added to at least one of them. Glass fibers, ceramic fibers such as alumina, nylon fibers, carbon nanotubes, and the like can be shortened and mixed. In general, a thin film thermally separated from a substrate is generally formed on a cavity. When a photoresist film is used as the thin film, a highly precise hole having a predetermined shape can be easily formed at a desired position of the thin film.

However, in general, a photoresist film is an organic thin film such as a PMMA film or a polyimide film. Therefore, in the case of a crosslinked structure that softly crosslinks a cavity or a diaphragm structure, the shape of the photoresist film can be maintained somewhat. Unlike thin films, loosening near the center of the cavity is often not negligible. In addition, in the thermal separation structure from the substrate with the cantilever structure, it is difficult to maintain the shape of the cantilever structure unless the film thickness is sufficiently large.

In the present invention, an additive-added photoresist in which a thin and short fiber such as a glass fiber is mixed in a liquid photoresist as an additive is applied to a substrate having a sacrificial layer, for example, in a necessary photolithography process. If the sacrificial layer is etched away after patterning into a desired shape, thermosetting, etc., this location becomes a cavity, and a thin film (heated from the substrate) floats above the cavity formed on the substrate. The separated thin film) can be composed of an additive-containing photoresist film containing fibers as additives. For example, on a substrate having a sacrificial layer such as aluminum (for example, 300 μm wide and 20 μm high) by mixing a thin and short glass fiber having a diameter of 1 μm (μm) and a length of about 10 μm into a liquid photoresist. If the coating is applied to a thickness of about 2 μm by spin coating, the length direction of the glass fiber is oriented along the surface of the substrate and the sacrificial layer, depending on the viscosity of the photoresist containing the additive (for spin coating, In many cases, the length direction of the glass fiber is directed in the direction of the centrifugal force of the rotation), and it is not necessary to jump out in the thickness direction of the photoresist with additive, and a substantially flat photoresist film with additive is formed. The glass fibers are arranged in the photoresist film coating layer while being in contact with each other, and the glass fibers are bonded to each other by thermosetting the photoresist film to form a strong additive-added photoresist thin film. After that, if the sacrificial layer such as aluminum is etched away with dilute hydrochloric acid or the like as an etchant, a three-dimensional structure of a photoresist thin film containing an additive thermally separated from a substrate with little slack floating in the air is formed. Of course, if a temperature sensor such as a thermopile and an infrared absorbing film are formed on the photoresist thin film containing additives thermally separated from the substrate floating in the air, a thermal infrared sensor can be provided, and a thin film heater and If formed in combination with a temperature sensor, a flow sensor or the like can be provided. In this way, a three-dimensional structure consisting mostly of an additive-added photoresist can be provided, except for temperature sensor and thin film heater materials.

Since the photoresist with an additive is a photosensitive material, it can be patterned into an arbitrary shape by photolithography. Apply additive-patterned photoresist, pattern it, and form a thin film temperature sensor, thin-film heater, electrode, etc. on it, then repeat these steps to form a three-dimensional multilayered thin film of additive-added photoresist film You can also It is also possible to conduct with a metal pattern using a through hole in which electrodes between the multiple layers are formed in the photoresist film containing an additive. In this way, a highly functional sensor can be realized by a highly sensitive sensor or a combination of sensors. When forming a through-hole, it is better to make the diameter larger than the length of the glass fiber as an additive.

When forming a three-dimensional structure floating in the air with a thin film, since the strength of the thin film structure is important, a photoresist film containing an additive such as glass fiber is suitable, but the region formed on the substrate is simply Since it is not always necessary to have bending strength when used as an insulating film, an ordinary photoresist film containing no additive may be suitable. In such a case, a structure in which an ordinary photoresist film region and an additive-added photoresist film region are combined can be used.

The additive-containing photoresist structure according to claim 3 of the present invention is a case where the fiber is transparent to the wavelength of ultraviolet rays used for patterning the photoresist .

In general, ultraviolet light is used for exposure of the photoresist. If there are solids or scatterers that are opaque to this UV light in the photoresist, they will leave the photoresist area underneath them unexposed, and in the case of negative photoresists this unexposed state. In the region, the photoresist component is dissolved by development, and the photoresist containing the additive is lost. Therefore, it is important to select a transparent additive material for the ultraviolet rays for exposure. In addition, it is possible to use scattered light for exposure of the shadowed portion of the additive by increasing the thickness, but even a transparent additive has reflection and scattering from the surface, so it can be used as a photoresist when there is no additive. On the other hand, it is necessary to lengthen the exposure time.

The additive-containing photoresist structure according to claim 4 of the present invention is such that the size of the fiber mixed in the additive-containing photoresist is smaller than the minimum thickness of the structure formed by the additive-containing photoresist. This is a case where the length is shorter than the pattern length.

This is a case where a fiber is used as an additive of a photoresist containing an additive. When a predetermined pattern is formed, if the diameter of the fiber is not smaller than the thickness of the photoresist film (if it is not thin), the photoresist film is made of the fiber. Therefore, it will be uneven. Further, for example, when the hole formed in the photoresist film is patterned by exposure and development, if the length of the fiber is larger than the diameter of the hole, there is a problem that the hole is blocked with the fiber. Further, even when it is desired to leave a pattern of an elongated photoresist film on the substrate, if the length of the fiber is larger than the width of the pattern, the fiber protrudes greatly from the pattern, and an accurate pattern cannot be formed. However, if the length of the fiber is equal to or smaller than the width of the pattern, the pattern can be formed with an accuracy about the width of the pattern. Also, a sacrificial layer is formed on the substrate, and an additive-added photoresist is coated thereon, patterned and cured, and then the sacrificial layer is etched away to form a cavity, whereby the additive-containing photoresist film is structured. When the length of the fiber is larger than the thickness of the sacrificial layer, the fiber jumps out of the bridge at the leg portion of the bridge. Since the size of the leg of the bridge is determined by the thickness of the sacrificial layer, it is important to adjust the length of the fiber as an additive so that the length of the fiber is shorter than the thickness of the sacrificial layer.

The photoresist structure containing an additive according to claim 5 of the present invention is a photoresist structure made of a thermosetting product of a photoresist pattern containing an additive, and includes a solid additive that does not dissolve in the photoresist. Yes and, the additive and the fiber, as the additive, in addition to the fibers, is characterized in that the mixed blowing agent.

When a rubber-based photoresist is used, for example, it softens at about 200 ° C., so a foaming agent that foams at this temperature can be used as an additive. Sodium hydrogen carbonate is a solid white powder, which generates carbon dioxide when heated and becomes a foaming agent. The white powder is thermally decomposed at 270 ° C., but when it contains moisture, the decomposition temperature decreases. It is also transparent to ultraviolet rays, and becomes almost transparent when sufficiently mixed with a liquid photoresist. Also, azodicarbonamide, which is an organic foaming agent, is an orange fine powder and is foamed together with an auxiliary agent. The decomposition temperature is 200 ° C., and the decomposition temperature can be adjusted by the combined use with a zinc compound. Thus, a foaming agent and an auxiliary agent can be combined to make an additive. Carbon dioxide gas or nitrogen gas is generated by these foaming agents, and the volume of the softened photoresist film is expanded by generating fine bubbles in the photoresist portion of the photoresist containing the additive, for example, to become a sparse material. Therefore, it can be used as a heat insulating material.

The photoresist structure with an additive according to claim 6 of the present invention is the photoresist structure with an additive according to claim 5, wherein the photoresist is expanded on the substrate by foaming treatment .

As an additive-added photoresist, it may be a negative type or a positive type, but in addition to the fiber, a foaming agent or an auxiliary agent may be mixed in the liquid photoresist, and this may be applied to the substrate, In addition to the fiber, an additive-added photoresist mixed with a foaming agent and an auxiliary agent is in the form of a sheet, which may be formed by pasting it on a substrate. This is the case where after the exposure and development processing, a firing process is performed to expand the photoresist.

The foaming agent is not necessarily decomposed by heating. For example, the foaming agent may be irradiated with the absorption wavelength of the foaming agent to be foamed by a photochemical reaction, or immersed in a liquid chemical and chemically reacted with the mixed foaming agent. It can also be made to foam in this way.

The photoresist structure with an additive may be formed using an additive-added photoresist in which the above-described fiber or a foaming agent is added to at least a part of the structure .

The thermal decomposition temperature for foaming can be adjusted by appropriate selection of organic and inorganic foaming materials and auxiliaries. Needless to say, a planar or three-dimensional structure can be formed by using a photoresist containing an additive as a part of a structure such as metal or ceramic.

Moreover, a foaming agent containing a fiber and an auxiliary agent can be mixed as an additive of the photoresist containing the additive. The photoresist composition of the additive-containing photoresist, because it patterned by easily exposed, it is also possible to form the desired additive-filled bulging foamed shape photo registry structure body. Since the fiber is contained, a planar or three-dimensional structure having higher strength can be provided.

Since the bending strength of a plate is generally proportional to the cube of the thickness of the plate, for example, when the thickness is doubled, a bending strength of 8 times is obtained. In this way, it becomes a thick film effectively, so it forms a structure consisting of a thin film floating in the air with high bending strength by using it as a material of a thin film floating in the air that is thermally isolated from the substrate while having a heat insulating structure. can do.

In the photoresist structure containing an additive of the present invention, a photoresist that can easily form a pattern shape of a desired shape by coating and exposure, and a solid additive having various functions can be added thereto. There is an advantage that a planar or three-dimensional structure having a desired shape and a necessary function can be formed.

In the photoresist structure containing an additive of the present invention, when a thin and short fiber is mixed as an additive of the photoresist and a material transparent to the wavelength of the light source for exposure is used, exposure of a desired pattern can be achieved. There is an advantage that a thin film with little bending or slack can be formed with a predetermined shape, for example, a bridge, a cantilever or a dial-lam thin film formed in the air above the cavity.

In the photoresist structure containing an additive of the present invention, a foaming agent is mixed, and after patterning by exposure, development and selection by selecting a decomposition temperature of the foaming agent, the photoresist film which is a thin film is initially heated and softened. In this state, a planar or three-dimensional structure in a thick film state can be formed by volume expansion by fine foaming at the thermal decomposition temperature of the foaming agent.

Since the additive-containing photoresist structure of the present invention can be made into a sparse material by firing, the thermal conductivity is reduced and a planar or three-dimensional structure of a heat-insulating photoresist can be formed. Furthermore, it is possible to form a thin film suspended in the air in combination with a cavity. For example, it is difficult to form a cantilever structure with only a photoresist film because the bending strength is small. However, since the thickness can be effectively increased by expansion due to foaming, there is an advantage that a long cantilever structure can be formed. is there.

In the photoresist structure containing an additive according to the present invention, the multilayer film structure of the photoresist film is advantageous in that it has higher strength and can easily form a desired thick film.

In the photoresist structure containing an additive according to the present invention, a structure having higher strength can be formed by mixing various transparent additives such as fibers and foaming agents, and other materials such as metals and ceramics can be used. There is an advantage that a larger structure can be provided in combination with the structure.

It is the cross-sectional schematic which shows one Example for demonstrating the concept of the additive photoresist of the fiber used as the material of the photoresist structure containing an additive of this invention, and is the case where it implements using a fiber as an additive. (Example 1) FIG. 5 is a schematic cross-sectional view showing another embodiment of the concept of an additive-added photoresist that is a material of an additive-added photoresist structure of the present invention, when the fiber and foaming agent are used as additives. It is. (Example 2) The additive-containing photoresist thin film used as the material of the additive-containing photoresist structure of the present invention, when the fiber and the foaming agent are used as the additive in FIG. It is a cross-sectional schematic diagram of a planar structure. (Example 2) It is the cross-sectional schematic which shows one Example at the time of forming the cantilever structure which is a three-dimensional structure as a photoresist structure containing an additive of this invention. (Example 3) FIG. 5 is a schematic cross-sectional view showing an enlarged view when a fiber is used as an additive in the case where the cantilever structure as the additive-containing photoresist structure of the present invention shown in FIG. 4 is formed. (Example 3) It is a photoresist structure containing an additive of the present invention, and is a schematic cross-sectional view showing an embodiment when the thermosensor is used as a temperature sensor and a thermal infrared sensor is used. Example 4 It is a photoresist structure containing an additive according to the present invention, and is a schematic cross-sectional view showing another embodiment of a thermo-type infrared sensor using a thermopile as a temperature sensor. (Example 5) It is a photoresist structure containing an additive of the present invention, and is a schematic cross-sectional view showing an example when the thermosensor is used as a temperature sensor and the flow sensor is used. (Example 6)

Hereinafter, examples of the photoresist containing an additive of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a schematic configuration diagram showing an embodiment for explaining the concept of a fiber-added photoresist 6 as a material of an additive-containing photoresist structure 11 of the present invention. This is a case where the fiber 4 is used. When the fiber 4 which is a glass fiber is mixed in the photoresist 2 on the board | substrate 1, the mode of the photoresist 6 with the liquid additive before spin coating is shown. As the glass fiber, for example, when spin-coating to a thickness of about 2 micrometers (μm), it is better to use a fiber having a diameter of 1 μm or less. Further, when a contact hole or the like is formed in the coated photoresist film containing an additive by exposure and development, it is preferable that the fiber diameter is smaller than the diameter of the contact hole. For example, when the diameter of the contact hole is 20 μm, it is preferably 20 μm or less, for example, about 10 μm. When a bridge having a cavity is formed on the substrate 1 with a photoresist film containing an additive, the length of the glass fiber is preferably the same as or smaller than the height of the cavity that is the height of the pier.

Figure 2 is a cross-sectional schematic view showing another embodiment for explaining an additive containing concepts of the photoresist 6 as a material for the additive-containing photoresist structure 11 of the present invention, the fiber 4 as an additive 3 This is a case where the foaming agent 5 is used. A state in which a foaming agent 5 is mixed in the photoresist 2 and a photoresist containing a liquid additive before spin coating is placed on the substrate 1 is shown. As the foaming agent 5, for example, sodium hydrogen carbonate, ammonium carbonate, or the like can be used. Sodium hydrogen carbonate is a white powder and has a thermal decomposition temperature of about 270 ° C., but can be adjusted to about 200 ° C. or lower by containing some water. When the sodium hydrogen carbonate powder is sufficiently mixed with the photoresist 2, the photoresist 2 becomes a photoresist with a transparent liquid additive that is almost pale yellow, which is the color of the photoresist 2.

Figure 3 is a thin film of the additive-containing photoresist 6 as a material for the additive-containing photoresist structure 11 of the present invention, the additive-containing photoresist structure was performed using a foaming agent 5 and fiber 4 as an additive in FIG 11 shows the state of the photoresist 12 containing an additive expanded by the firing 7, and is a case where the film is patterned and then expanded by foaming to be a thick film state. Since the rubber-based photoresist 2 can be softened when the temperature is raised to about 200 ° C., the thick film expanded by the foam 7 due to thermal decomposition at this temperature is the thin film 9 of the sparse photoresist 2 (actually, The structure 11 is a thick film. The thin film 9 of the sparse photoresist 2 has a low thermal conductivity and is thermally insulating, and can be used as a thin film having a planar structure thermally separated from the substrate 1. Since the volume of the thin film 9 patterned with the foaming agent 5 is expanded to increase the volume, it is necessary to consider the dimensions of the thin film 9 due to the expansion at the time of pattern design. The figure also shows that the elution portion 8 of the pattern is a hole in the photoresist film.

In the above description, sodium hydrogen carbonate inorganic foaming agent 5 is used. However, azodicarbonamide, which is an organic foaming agent, is an orange fine powder and is foamed together with an auxiliary agent. The decomposition temperature is 200 ° C., and the decomposition temperature can be adjusted by the combined use with a zinc compound as an auxiliary agent. Thus, a foaming agent and an auxiliary agent can be combined to make an additive.

FIG. 4 is a schematic cross-sectional view showing an embodiment in which a cantilever structure which is a three-dimensional structure as the photoresist structure 11 with an additive of the present invention is formed. A sacrificial layer is formed of aluminum or the like on a substrate 1 such as a silicon single crystal, and an additive-added photoresist 6 is applied thereon by spin coating or the like, and patterned and heated by exposure and development to form a cantilever structure. After curing, the sacrificial layer is removed by etching to form the cavity 10. In this way, the cantilever structure- added photoresist structure 11 can be formed. By adding the fiber 4 or the foaming agent 5 as an additive, a cantilever structure-added photoresist structure 11 with increased strength can be obtained. Generally, since the bending strength of a film is proportional to the cube of its thickness, the bending strength can be rapidly increased as the thickness increases. Thus, increasing the thickness of the thin film due to the foaming effect of the foaming agent leads to an increase in the bending strength of the film. Further, both the fiber 4 and the foaming agent 5 can be added as the additive 3 to further increase the strength. A thin film heater 35, a temperature sensor, or the like may be formed on the three-dimensional structure 11 having the cantilever structure, and a flow sensor or a thermal infrared sensor may be formed.

Further, in FIG. 5, in the case of forming a cantilever structure as an additive-containing photo registry structure Zotai 11 of the present invention shown in FIG. 4 is an enlarged view of a case where the additive 3 were used fiber 4. A very thin and short fiber (for example, a diameter of about 0.5 μm and a length of about 10 μm) is used as the additive 3 in the photoresist 6 containing the additive, and the fibers 4 stick to each other to increase the strength of the thin film 9. .

6, as an additive-containing photo registry structure Zotai 11 of the present invention, is a cross-sectional schematic view showing an embodiment in carrying out the thermopile 13 as thermal infrared sensor and the temperature sensor. A film of a photoresist 6 containing an additive is applied to a substrate 1 that is easy to etch into a cavity 10 formed in advance on the (100) surface of a silicon single crystal and is filled with a sacrificial material such as zinc having a low melting point. A desired pattern is formed by exposure, development, and the like, and a thermopile 13 and an infrared absorption film 25 are further formed thereon by a known technique, and then the sacrificial material is removed by etching to form the cavity 10. In this manner, the photoresist structure 11 containing the additive is formed in such a manner that the light receiving portion 15 of the thermal infrared sensor is thermally separated from the substrate 1. Here, the contact point B19 (for example, a warm contact point) of the thermopile 13 is formed near the center of the light receiving unit 15 floating in the air, and a photoresist film for forming a uniform temperature region near the center. This is a case where the heat conductive thin film 26 such as a thick metal film is formed through the insulating layer 28 by the above. It is possible to obtain a cantilever structure- added photoresist structure 11 with increased strength by adding the fiber 4 or the foaming agent 5 as an additive to the additive-containing photoresist 6. Further, both the fiber 4 and the foaming agent 5 can be added as additives to further increase the strength. The expansion of the thickness of the thin film 9 caused by the foaming agent 5 results in a sparse thin film 9 that can reduce the thermal conductivity and increase the bending strength by increasing the thickness. Therefore, the infrared light receiving part 15 with less slack can be formed.

7, as an additive-containing photo registry structure Zotai 11 of the present invention, is a cross-sectional schematic view showing another embodiment in carrying out the thermopile 13 as thermal infrared sensor and the temperature sensor. In this example, the cavity 10 is formed above the substrate 1. In the cavity 10, a sacrificial layer is formed in this portion, a photoresist 6 containing an additive is formed thereon, patterned by photolithography, and cured to form a thermopile 13, an infrared absorption film 25, and the like. Later, the sacrificial layer can be formed by etching away. Since the cavity 10 is formed above the substrate 1, an integrated circuit 110 including a system including an amplifier, an arithmetic circuit, and further a drive circuit is formed directly below the light receiving unit 15 on the substrate 1. It is. Further, since the thermopile 13 is a temperature difference sensor, the absolute temperature sensor 34 such as a diode or a transistor is also formed on the substrate 1. Further, this is a case where the contact A18 (for example, a cold junction) of the thermopile 13 is formed on the substrate 1 having a large heat capacity. The output of the thermopile 13 can be taken out through a diffusion region 32 formed on the substrate 1.

FIG. 8 shows an example of the case where the photoresist structure 11 with an additive of the present invention is implemented as a flow sensor such as a gas for forming a thermopile and a thin film heater and measuring the flow of a fluid such as a gas as a heat conduction type sensor. It is a cross-sectional schematic diagram which shows an example.

When implemented as a gas flow sensor for gas flow measurement as a heat conduction type sensor, a current is passed through the thin film heater 35 via the heater electrode 65 so that the temperature is raised, for example, by about 10 ° C. from room temperature in the absence of wind. The current value is set to and driven. When the thin film 9 of the photoresist 6 containing additives is exposed to a gas flow, the heated thin film 9 is deprived of heat and cooled, and the output change of the thermopile 13 based on the temperature difference and temperature change at that time is measured. The amount of gas flow can be measured using calibration data prepared in advance. A gas flow sensor can be provided by such a principle.

In this embodiment, slits 36 are formed in the thin film 9, and the thin film 9 on the downstream side and the thin film 9 on the upstream side in the airflow direction are compared to the thin film 9 near the center of the bridge structure where the thin film heater 35 is formed. However, it is set as the structure connected with the same thin film 9 near the center of a bridge | crosslinking structure. Through this connecting portion, the thin film 9 on the downstream side receives the heat of the thin film heater 35 and rises in temperature. In a windless state, the temperature of the contact point B19 (hot contact point) near the center of the downstream thin film 9 and the upstream thin film 9 is several degrees lower than the temperature at the center of the thin film heater 35, but is substantially the same. Yes. If there is an air flow, the heat of the thin film heater 35 further heats the thin film 9 on the downstream side, but the thin film 9 on the upstream side is cooled by the air flow at the ambient temperature, causing a temperature drop. At this time, a minute air flow and a change in the air flow are measured from the output difference of the thermopile 13 formed in the downstream thin film 9 and the upstream thin film 9 by using calibration data prepared in advance. be able to. Of course, the size of the airflow can also be measured using single output data of each thermopile 13. In this embodiment, an absolute temperature sensor 34 for measuring a reference absolute temperature is formed on a silicon substrate 1.

Needless to say, the photoresist structure 11 with an additive of the present invention is not limited to this example, and various modifications can be naturally made while the gist, operation and effect of the present invention are the same.

Additives containing photoresist 6 for use in the additive-containing photoresist structure 11 of the present invention has a fiber 4 and is further mixed and foaming agent 5 as an additive 3, exposure, after developing the patterned, these The additive 3 is also left on the substrate 1 in a mixed state. Since the photoresist structure 11 containing an additive is formed by adding a fiber 4 such as a glass fiber, the strength of the thin film 9 is increased, so that the three-dimensional additive-added photoresist structure 11 can also stand by itself. Further, since the film thickness can be increased by foaming due to the mixing of the foaming agent 5, the strength of the thin film 9 is increased, and the planar or three-dimensional additive-containing photoresist structure 11 by the additive-containing photoresist 6 is also photosensitive. Since the resin photoresist 2 is used, it is reproducible, and a uniform shape can be obtained even when mass-produced, and can be easily formed into a desired shape by photolithography. A thermopile as a temperature sensor is formed in the photoresist structure 11 with additives , and an infrared radiation thermometer or an image sensor, particularly an ear-type thermometer, which needs to measure a minute temperature difference with high accuracy and high sensitivity. As a sensor for detecting a gas such as hydrogen by measuring a minute heat generation in a combustible gas sensor such as hydrogen, or a heat conduction sensor, it is also promising as a temperature difference sensor. It is also possible to provide an optimum structure for temperature difference measurement, such as a flow sensor for liquids or gases with a very small flow rate, a thin film Pirani vacuum gauge, a pressure sensor such as a thermal humidity sensor or an atmospheric pressure sensor. Needless to say, not only a sensor but also a fine planar or three-dimensional structure can be provided.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Photoresist 3 Additive 4 Fiber 5 Foaming agent 6 Additive containing photoresist 7 Foam 8 Pattern resist elution part 9 Thin film 10 Cavity 11 Additive photoresist structure 12 Expanded additive containing photoresist 13 Thermopile 15 Light receiving part 16 Thermoelectric conductor A
17 Thermoelectric conductor B
18 Contact A
19 Contact B
20 Wiring 21A, 21B Electrode terminal A
22A, 22B Electrode terminal B
23 Electrode 25 Infrared absorbing film 26 Thermal conductive thin film 28 Insulating layer 30 Contact hole 31 Ohmic contact 32 Diffusion region 34 Absolute temperature sensor 35 Thin film heater 36 Slit 37 Etching hole 51 Silicon oxide film 65 Heater electrode 110 Integrated circuit

Claims (6)

A three-dimensional structure having a thin film suspended in the air, which is made of a thermosetting product of a photoresist pattern containing an additive, in which a solid additive that does not dissolve is mixed in the photoresist. A photoresist structure containing an additive. The additive-containing photoresist structure according to claim 1, wherein the additive-containing photoresist pattern is a remaining portion of the additive-containing photoresist on the substrate. The additive-containing photoresist structure according to claim 1 , wherein the fiber is transparent to the wavelength of ultraviolet rays used for patterning the photoresist. 4. The fiber according to any one of claims 1 to 3, wherein the size of the fiber mixed into the additive-containing photoresist is smaller than the minimum thickness of the structure formed by the additive-containing photoresist and shorter than the minimum pattern length of the structure. A photoresist structure containing the additive according to 1. A photoresist structure composed of a thermoset of a photoresist pattern containing an additive, in which a solid additive that does not dissolve is mixed in the photoresist, the additive is a fiber , and the additive is Besides, additives containing photoresist features you characterized in that mixed with the foaming agent of said fiber. 6. The photoresist structure with additives according to claim 5, wherein the photoresist is expanded on the substrate by foaming .

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