KR20230000318A - Method for Manufacturing Bolometer Infrared Sensors to Minimize Output Change Due to High Temperature of Targets - Google Patents

Abstract

Disclosed is a method for manufacturing a bolometer infrared sensor to minimize output changes due to a high temperature of a target. The method for manufacturing a bolometer infrared sensor according to an embodiment of the present invention comprises the steps of: forming a contact pad on a sensor substrate containing a signal layer for transmitting electric signals of a signal obtaining circuit; forming a thermal conducting layer and a resistance body layer on the contact pad; forming holes on both ends of the thermal conducting layer and the resistance body layer; forming a support pillar in the hole and a blocking film layer on the resistance body layer; and forming a connection leg layer in order that one side thereof is connected to the support pillar and the other side thereof is connected to the resistance body layer.

Description

Method for Manufacturing Bolometer Infrared Sensors to Minimize Output Change Due to High Temperature of Targets}

The present invention relates to a manufacturing method of a bolometer infrared sensor for minimizing an output change caused by a target exposed to high temperature.

The contents described in this section simply provide background information on the embodiments of the present invention and do not constitute prior art.

The core of the bolometer infrared sensor is to convert the change in temperature due to absorbing infrared energy incident from the target object into a change in electrical resistance, and to read the change in current due to this change in electrical resistance through a signal acquisition circuit. .

The reference cell must generate a constant offset current without reacting to the infrared energy so that only the current component modulated by the infrared energy can be detected by removing the basic current flowing in the reactant cell. For this reason, since the thermal conductivity must be designed to be large so that heat can escape well, it is mainly composed of a form in which the resistor is directly connected to the support column without a connecting bridge, or an additional thermal conductivity having high thermal conductivity is composed, or on the sensor substrate It is composed directly without any gaps.

In the case of a structure having high thermal conductivity, there is no problem in use in general cases, but non-uniformity of the image is caused when infrared rays are incident from a high-temperature target. That is, when high infrared energy is incident from a high-temperature target such as the sun, the absorbed infrared energy is not emitted and pattern noise is generated in an image. In order to solve this problem, a reflector is formed on the surface of the reference cell to minimize infrared absorption. Each company utilizes a structure with high thermal conductivity, or forms a reflective layer directly on the blind cell, or forms a reflective structure on top of the reflective layer by spacing it apart. take the way When forming a barrier film in contact with the top of a reference cell, the residual heat of the operating current does not escape as the thermal capacity increases, and the temperature of the reference cell is raised to impair thermal stability at high temperatures. Korean Patent Registration No. 10-1442811 describes it. .

However, in the case of forming an additional reflective layer (blocking film), the number of steps in the manufacturing process of the bolometer infrared sensor is increased, and it becomes a factor in cost increase and yield decrease due to semiconductor process characteristics.

The present invention relates to a bolometer-type infrared sensor that absorbs infrared rays and modulates them into electrical signals, and minimizes output change caused by a high-temperature target to improve output signal uniformity deterioration due to unwanted temperature change of a reference cell caused by the high-temperature target. The main object is to provide a method for manufacturing a bolometer infrared sensor for

According to one aspect of the present invention, a method for manufacturing a bolometer infrared sensor for achieving the above object includes forming a contact pad on a sensor substrate including a signal layer for transmitting an electrical signal of a signal acquisition circuit; forming a thermal conduction layer and a resistor layer on the contact pad; forming a cavity at both ends of the thermal conduction layer and the resistor layer; forming a support pillar in the cavity and forming a blocking film layer on the resistor layer; and forming a connection bridge layer such that one side is connected to the support pillar and the other side is connected to the resistor layer.

As described above, the present invention has the effect of providing a bolometer infrared sensor capable of minimizing output change in a high-temperature environment by adding a barrier layer to the reference cell.

In addition, the present invention has the effect of reducing the manufacturing cost and increasing the yield by adding a barrier layer to the reference cell without adding a process step of manufacturing the bolometer infrared sensor.

1 is a diagram showing an infrared detector including a bolometer infrared sensor according to an embodiment of the present invention.
2A and 2B are diagrams showing a reference cell of a bolometer infrared sensor according to a first embodiment of the present invention.
3 is a diagram for explaining a manufacturing process of a reference cell according to a first embodiment of the present invention.
4A and 4B are diagrams showing a reference cell of a bolometer infrared sensor according to a second embodiment of the present invention.
5 is a diagram for explaining a manufacturing process of a reference cell according to a second embodiment of the present invention.
6A and 6B are diagrams showing a reactive cell of a bolometer infrared sensor according to an embodiment of the present invention.
7 is a view for explaining a manufacturing process of a reactant cell according to an embodiment of the present invention.
8 is a circuit diagram illustrating a detection circuit in which a reactant cell and a reference cell are connected to a signal acquisition circuit according to an embodiment of the present invention.
9 is an exemplary diagram illustrating the output of an infrared image using a bolometer infrared sensor according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted. In addition, although preferred embodiments of the present invention will be described below, the technical idea of the present invention is not limited or limited thereto and can be modified and implemented in various ways by those skilled in the art. Hereinafter, a bolometer infrared sensor for minimizing an output change by a high-temperature target proposed in the present invention will be described in detail with reference to the drawings.

1 is a diagram showing an infrared detector including a bolometer infrared sensor according to an embodiment of the present invention.

1(a) shows the infrared detector 10, and FIG. 1(b) shows the configuration of the infrared detector 10. An infrared detector 10 according to the present embodiment includes an infrared window 100, an infrared sensor 200, and a feed through 300. The infrared detector 10 of FIG. 1 is according to an embodiment, and all blocks shown in FIG. 1 are not essential components, and some blocks included in the infrared detector 10 in another embodiment are added, changed, or deleted. It can be.

The infrared detector 10 refers to a transducer that absorbs infrared rays and modulates them into electrical signals. The inside of the infrared detector 10 is kept in a vacuum state to preserve the absorbed infrared energy.

The infrared window 100 selectively transmits only infrared wavelengths.

The infrared sensor 200 refers to a semiconductor sensor that absorbs infrared rays and modulates them into electrical signals.

The infrared sensor 200 refers to a bolometer-type infrared sensor that absorbs infrared rays and modulates them into electrical signals.

The infrared sensor 200 may be implemented in a form including at least one of a reactant cell 210 and a reference cell 220 .

The reactant cell 210 performs an operation of absorbing infrared energy and generating an electrical signal with a resistance change according to a temperature change. The configuration of the reactant cell 210 will be described in detail with reference to FIGS. 6 and 7 .

The reference cell 220 performs an operation of not absorbing infrared rays in order to amplify only the magnitude of the modulated current by removing the reactant cell 210 and the basic current that is not modulated by the reactant cell 210 . The configuration of the reference cell 220 will be described in detail with reference to FIGS. 2 to 5 .

The feedthrough unit 300 transmits an input for operation of the infrared sensor 200 and an electrical output generated by infrared rays to the outside.

2A and 2B are diagrams showing a reference cell of a bolometer infrared sensor according to a first embodiment of the present invention.

2A is a plan view of the reference cell 220 of the bolometer infrared sensor according to the first embodiment, and FIG. 2B is a cross-sectional view of the reference cell 220 of the bolometer infrared sensor according to the first embodiment.

In general, a reference cell generates a constant offset current without reacting to infrared energy so that only a current component modulated by infrared energy can be detected by removing a basic current flowing in a reactant cell. For this reason, since the reference cell must be designed with high thermal conductivity so that heat can escape well, it is mainly composed of a form in which a resistor is directly connected to the support column without a connecting leg, or an additional heat conductor having high thermal conductivity is composed, or It may be configured in a form in contact with the sensor substrate without spacing.

However, when high infrared energy is incident, all of the infrared energy absorbed by the reference cell cannot be discharged, resulting in image distortion.

The reference cell 220 of the bolometer infrared sensor according to the first embodiment has a structure for improving output signal uniformity deterioration due to unwanted temperature change of the reference cell caused by a high-temperature target.

The reference cell 220 according to the first embodiment forms a blocking film that does not absorb infrared rays in order to fundamentally block image distortion caused by not emitting all of the absorbed infrared energy.

In the reference cell 220 according to the first embodiment, when the support pillar 224 formed to support the structure and transmit electrical signals is formed, the blocking film layer 20 is simultaneously generated to generate infrared energy without a separate additional manufacturing process. It is possible to prevent image distortion caused by not being able to discharge all of them. The support pillar 224 and the blocking film layer 20 according to the first embodiment may be formed of metal materials such as titanium (Ti), nickel (Ni), copper (Cu), and aluminum (Al). The thickness of the blocking film layer 20 is preferably formed to be 100 nm or more, and preferably has a thickness capable of reflecting infrared rays in the 8 to 14 μm long wavelength infrared (LWIR) wavelength band.

On the other hand, in the first embodiment, it is assumed that the reference cell is designed so that the heat conduction layer 228 remains so that the absorbed infrared energy escapes to the signal acquisition circuit board 227.

Hereinafter, the configuration of the reference cell 220 of the bolometer infrared sensor according to the first embodiment will be described.

The reference cell 220 according to the first embodiment includes a sensor substrate 227, a contact pad 225, a support pillar 224, a connection bridge layer 22, a resistor layer 21, a barrier film layer 20, and a heat exchanger. and a conductive layer 228 .

The sensor substrate 227 includes a signal layer 226 for transmitting electrical signals of the signal acquisition circuit.

The contact pad 225 is formed between the signal layer 226 of the sensor substrate 227 and the support pillar 224, and is formed for electrical connection. Here, the contact pad 225 is generally formed on the same plane as the reflective pad 215 of the reactant cell 210, and is mainly formed by using a metal such as aluminum, titanium, or gold having high infrared reflectivity.

The support pillar 224 is formed between the connection bridge layer 22 connected to the resistor layer 21 and the contact pad 225 .

The support pillar 224 has one side connected to the contact pad 225 and the other side connected to the connection bridge layer 22 . The support pillar 224 is formed of one metal of titanium (Ti), nickel (Ni), copper (Cu), and aluminum (Al) or an alloy of at least one metal.

The support pole 224 includes a recess U at the center of the pole. The concave portion of the support pillar 224 is preferably formed such that the thickness of the support pillar 224 is 0.1 μm to 1 μm, but is not necessarily limited thereto. On the other hand, when the thickness of the support pillar 224 is less than 0.1 μm, it is difficult to perform the supporting role, and when the thickness of the support pillar 224 exceeds 1 μm, the efficiency of electrical connection is reduced.

The connection bridge layer 22 includes a connection bridge portion 221a and a connection bridge metal layer 221b.

The connection bridge layer 22 includes a connection bridge portion 221a for transmitting an electrical signal by connecting the signal layer 226 and the resistor 223a, and a connection bridge metal layer 221b connected to the connection bridge portion 221a. . In addition, the connection bridge layer 22 may include an insulator 222 to protect the connection bridge portion 221a and the connection bridge metal layer 221b. Here, the connecting bridge portion 221a and the connecting bridge metal layer 221b are made of a metal having high conductivity and low thermal conductivity, such as titanium, chromium, nickel-chromium, or titanium alloy, or a conductive ceramic material.

The resistor layer 21 is connected to the connection bridge layer 22 . The resistive layer 21 includes a resistive layer 223a and a protective layer 223b.

A partial area of the resistance layer 223a is connected to the connection bridge portion 221a and the connection bridge metal layer 221b in a form of contact.

The protective layer 223b is formed to cover the upper and lower surfaces of the resistive layer 223a and is made of an insulating material.

The blocking layer 20 is formed in contact with the resistor layer 21 to block infrared rays. Here, the blocking film layer 20 may include a blocking film 229a and a blocking film protective layer 229b.

The blocking film 229a is formed to have a predetermined separation distance from the connection bridge layer 22 . Here, the predetermined separation interval is preferably between 0.1 μm and 2 μm.

In addition, the blocking film 229a is formed of the same material as that of the support pillar 224 . That is, the blocking film layer 20 may be formed simultaneously in the process of forming the support pillar 224 .

The blocking layer 229a may be formed of one of titanium (Ti), nickel (Ni), copper (Cu), and aluminum (Al) or an alloy of at least one metal. The blocking film protective layer 229b may be formed of an insulator.

The blocking film layer 20 according to the first embodiment is formed on the upper surface of the resistor layer 21 and may be formed in a rectangular shape. When the blocking film layer 20 is formed in a rectangular shape, it is formed to a thickness of 100 nm or more, and is preferably formed to a thickness capable of reflecting infrared rays in a long wavelength infrared (LWIR) wavelength band of at least 8 to 14 μm.

On the other hand, the upper surface of the rectangular shape of the blocking film layer 20 is formed such that the upper surface of the insulating layer 222 surrounding one end of the support pillar 224 is the same height as the blocking film layer 20, or the support pillar It may be formed at a height of 0.1 μm to 1 μm higher than the upper surface of the insulating layer 222 surrounding one end of the 224 . When the blocking film layer 20 is formed higher than the upper surface of the insulating layer 222, the infrared ray blocking rate can be further increased.

A thermal conduction layer 228 is located between the resistor layer 21 and the sensor substrate 227 . A portion of the thermal conductive layer 228 is connected to the sensor substrate 227 . The thermal conduction layer 228 allows the absorbed infrared energy to escape to the sensor substrate 227 .

3 is a diagram for explaining a manufacturing process of a reference cell according to a first embodiment of the present invention.

(a) of FIG. 3 shows step S310 of forming the contact pad 225 on the sensor substrate 227 .

In step S310 , a reflective material is deposited on the sensor substrate 227 and a partial region is etched to form the contact pad 225 . Here, the contact pad 225 may be formed using a metal material such as aluminum, titanium, or gold having high infrared reflectivity.

The contact pad 225 is formed to be electrically connected to the signal layer 226 of the sensor substrate 227 .

(b) of FIG. 3 shows step S320 of forming the thermal conduction layer 228 and the resistor layer 21 on the sensor substrate 227 and the contact pad 225 .

In step S320 , the thermal conductive layer 228 is preferentially deposited on the sensor substrate 227 and the contact pad 225 , and the resistor layer 21 is deposited on the thermal conductive layer 228 . Specifically, in step S320, the first passivation layer 223b, the resistive layer 223a, and the second passivation layer 223b are sequentially deposited on the heat conduction layer 228, and the resistive layer 223a and the second passivation layer 223a are formed. Both ends of the protective layer 223b are etched.

The heat conduction layer 228 formed in step S320 is formed for a λ/4 separation structure having a maximum light absorption efficiency. In addition, the resistance layer 223a is formed for an operation in which resistance is changed according to temperature change.

(c) of FIG. 3 shows a step S330 of forming a cavity for forming the support pillar 224 .

Step S330 forms a cavity for electrically connecting the signal layer 226 of the sensor substrate 227 and forming the support pillar 224 supporting the structure.

In step S330 , holes are formed at both ends of the second passivation layer 223b and the thermal conduction layer 228 through hole patterning and etching.

(d) of FIG. 3 shows a step S340 of forming the support pillar 224 and the blocking film layer 20 and forming the connection bridge layer 22 .

In step S340 , the blocking film layer 20 is formed on the resistor layer 21 while depositing the support pillar 224 in the previously formed cavity. That is, the blocking film layer 20 is formed simultaneously in the process of forming the support pillar 224 .

When high infrared energy is incident, the infrared energy absorbed by the reference cell 220 cannot be emitted, resulting in image distortion. In order to block this, the blocking film layer 20 is formed together when the support pillar 224 is formed.

The blocking film layer 20 is formed in a form in contact with the resistor layer 21 to block infrared rays, and is formed of the same material as the material of the support pillar 224 .

The support pillar 224 and the blocking film layer 20 may be formed of one metal selected from among titanium (Ti), nickel (Ni), copper (Cu), and aluminum (Al), or an alloy in which at least one metal is mixed.

After the support pillars 224 and the barrier film layer 20 are formed, the connection bridge layer 22 is formed in step S340.

The connection bridge layer 22 includes a connection bridge part 221a for transmitting an electrical signal by connecting the signal layer 226 and the resistor 223a, and a connection bridge metal layer 221b connected to the connection bridge part 221a. formed in the form In addition, the connection bridge layer 22 includes an insulator 222 to protect the connection bridge portion 221a and the connection bridge metal layer 221b.

In step S340, the blocking film layer 20 is formed on the upper surface of the resistor layer 21 and may be formed in a square shape. When the blocking film layer 20 is formed in a rectangular shape, it is formed to a thickness of 0.1 μm to 1 μm. In addition, the blocking film layer 20 is preferably formed to a thickness capable of reflecting infrared rays in a long wavelength infrared (LWIR) wavelength band of at least 8 μm to 14 μm.

Meanwhile, in step S340, the blocking film layer 20 is formed so that the upper surface of the rectangular shape of the blocking film layer 20 is at the same height as the upper surface of the insulating layer 222 surrounding one end of the support pillar 224. It can be.

In FIG. 3, it is described that each step is sequentially executed, but is not necessarily limited thereto. In other words, since it will be applicable to changing and executing the steps described in FIG. 3 or executing one or more steps in parallel, FIG. 3 is not limited to a time-series sequence.

4A and 4B are diagrams showing a reference cell of a bolometer infrared sensor according to a second embodiment of the present invention.

4A is a plan view of the reference cell 220 of the bolometer infrared sensor according to the second embodiment, and FIG. 4B is a cross-sectional view of the reference cell 220 of the bolometer infrared sensor according to the second embodiment.

The bolometer infrared sensor according to the second embodiment has a structure for improving output signal uniformity deterioration due to an unwanted temperature change of a reference cell caused by a high-temperature target.

The reference cell 220 according to the second embodiment has the same structure as the reference cell 220 according to the first embodiment described in FIGS. Descriptions will be omitted, and the differences in the blocking film layer 20 will be mainly described.

The blocking layer 20 is formed in contact with the resistor layer 21 to block infrared rays. Here, the blocking film layer 20 may include a blocking film 229a and a blocking film protective layer 229b.

In addition, the blocking film 229a is formed of the same material as that of the support pillar 224 . That is, the blocking film 229a may be formed simultaneously in the process of forming the support pillar 224 .

The blocking layer 229a may be formed of one of titanium (Ti), nickel (Ni), copper (Cu), and aluminum (Al) or an alloy of at least one metal. The blocking film protective layer 229b may be formed of an insulator.

The blocking film layer 20 according to the second embodiment is formed on the upper surface of the resistor layer 21 and may be formed in a mesh shape. When the blocking film layer 20 is formed in a mesh shape, each grid shape of the mesh shape is formed to a thickness of 0.1 μm to 1 μm. The mesh-shaped shielding film layer 20 has a lower heat capacity than the bulk-shaped shielding film, and can emit infrared energy faster.

The mesh-shaped blocking film layer 20 includes a structure in which a plurality of lattices are arranged, and the width of the lattice pattern may be 0.18 μm to 4 μm, and the width of the space formed between the lattices may be 0.18 μm to 4 μm. can Here, when the width of the lattice pattern of the mesh-shaped blocking film layer 20 is less than 0.18 μm or the width of the space exceeds 4 μm, it is difficult to implement the blocking film, and infrared blocking properties may be deteriorated. When the width of the lattice pattern of the mesh-shaped blocking film layer 20 exceeds 4 μm or the width of the space is less than 0.18 μm, the aperture ratio of the blocking film layer 20 is less than a preset threshold value, and the heat capacity increases.

On the other hand, the upper surface of the mesh shape of the blocking film layer 20 is formed such that the upper surface of the insulating layer 222 surrounding one end of the support pillar 224 is the same height as the blocking film layer 20, or the support pillar It may be formed at a height of 0.1 μm to 1 μm higher than the upper surface of the insulating layer 222 surrounding one end of the 224 .

5 is a diagram for explaining a manufacturing process of a reference cell according to a second embodiment of the present invention.

(a) of FIG. 5 shows step S510 of forming the contact pad 225 on the sensor substrate 227 .

In step S510 , a reflective material is deposited on the sensor substrate 227 and a partial region is etched to form the contact pad 225 . Here, the contact pad 225 is generally formed on the same plane as the reflective pad 215 of the reactant cell 210, and may be formed using a metal material such as aluminum, titanium, or gold having high infrared reflectivity. .

The contact pad 225 is formed to be electrically connected to the signal layer 226 of the sensor substrate 227 .

(b) of FIG. 5 shows step S520 of forming the thermal conduction layer 228 and the resistor layer 21 on the sensor substrate 227 and the contact pad 225 .

In step S520 , the thermal conductive layer 228 is preferentially deposited on the sensor substrate 227 and the contact pad 225 , and the resistor layer 21 is deposited on the thermal conductive layer 228 . Specifically, in step S520, the first passivation layer 223b, the resistive layer 223a, and the second passivation layer 223b are sequentially deposited on the heat conduction layer 228, and the resistive layer 223a and the second passivation layer 223a are deposited. Both ends of the protective layer 223b are etched.

The heat conduction layer 228 formed in step S520 is formed for a λ/4 separation structure having a maximum light absorption efficiency. In addition, the resistance layer 223a is formed for an operation in which resistance is changed according to temperature change.

(c) of FIG. 5 shows a step S530 of forming a cavity for forming the support pillar 224 .

Step S530 forms a cavity for electrically connecting the signal layer 226 of the sensor substrate 227 and forming the support pillar 224 supporting the structure.

In step S530 , holes are formed at both ends of the second passivation layer 223b and the thermal conduction layer 228 through hole patterning and etching. Here, etching may be etching using Cl and F-groups.

(d) of FIG. 5 shows step S540 of forming the support pillar 224 and the barrier film layer 20 and forming the connection bridge layer 22 .

In step S540 , the blocking film layer 20 is formed on the resistor layer 21 while depositing the support pillar 224 in the previously formed cavity. That is, the blocking film layer 20 is formed simultaneously in the process of forming the support pillar 224 .

When high infrared energy is incident, the infrared energy absorbed by the reference cell 220 cannot be emitted, resulting in image distortion. In order to block this, the blocking film layer 20 is formed together when the support pillar 224 is formed.

The blocking film layer 20 is formed in a form in contact with the resistor layer 21 to block infrared rays, and is formed of the same material as the material of the support pillar 224 .

The support pillar 224 and the blocking film layer 20 may be formed of one metal selected from among titanium (Ti), nickel (Ni), copper (Cu), and aluminum (Al), or an alloy in which at least one metal is mixed.

After the support pillars 224 and the barrier film layer 20 are formed, the connection bridge layer 22 is formed in step S540.

The connection bridge layer 22 includes a connection bridge part 221a for transmitting an electrical signal by connecting the signal layer 226 and the resistor 223a, and a connection bridge metal layer 221b connected to the connection bridge part 221a. formed in the form In addition, the connection bridge layer 22 includes an insulator 222 to protect the connection bridge portion 221a and the connection bridge metal layer 221b.

In step S540, the blocking film layer 20 is formed on the upper surface of the resistor layer 21 and may be formed in a mesh shape.

When the blocking film layer 20 is formed in a mesh shape, each grid shape of the mesh shape is formed to a thickness of 0.1 μm to 1 μm. The mesh-shaped shielding film layer 20 has a lower heat capacity than the bulk-shaped shielding film, and can emit infrared energy faster.

In step S540, the mesh-shaped blocking film layer 20 is formed in a structure in which a plurality of lattices are arranged, the lattice pattern may have a width of 0.18 μm to 4 μm, and the width of the space formed between the lattices is It may be formed from 0.18 μm to 4 μm.

Meanwhile, in step S540, the blocking film layer 20 is formed so that the upper surface of the mesh shape of the blocking film layer 20 is at the same height as the upper surface of the insulating layer 222 surrounding one end of the support pillar 224. It can be.

In FIG. 5, each step is described as sequentially executed, but is not necessarily limited thereto. In other words, since it will be applicable to changing and executing the steps described in FIG. 5 or executing one or more steps in parallel, FIG. 5 is not limited to a time-series sequence.

6A and 6B are diagrams showing a reactive cell of a bolometer infrared sensor according to an embodiment of the present invention.

6A is a plan view of the reactant cell 210 of the bolometer infrared sensor according to the present embodiment, and FIG. 6B is a cross-sectional view of the reactant cell 210 of the bolometer infrared sensor according to the present embodiment.

The reactant cell 210 of the bolometer infrared sensor absorbs infrared rays and changes resistance to generate a modulated current signal.

The reactant cell 210 is thermally isolated by being designed with low thermal conductivity in order not to lose the heat absorbed by the absorber layer 30 and the absorber layer 30 to the sensor substrate 217 including the signal acquisition circuit. A form including a support pillar 214 that separates the connection bridge layer 32, the absorber layer 30, and the bottom window layer 31 from the sensor substrate 217 by about λ/4 to have the maximum absorption rate. consists of Here, λ means a wavelength of 8 μm to 14 μm. In terms of a light absorption mechanism, it is preferable to implement a λ/4 structure (for example, 2 to 3.5 μm) at a distance between the absorption layers in the reflector 215 in order to have maximum absorption efficiency.

The resistor layer 31 is connected to the connection bridge layer 32 . The resistive layer 31 includes a resistive layer 213a and a protective layer 213b.

A partial area of the resistance layer 213a is connected to the connection bridge portion 211a and the connection bridge metal layer 211b in a form of contact.

The protective layer 213b is formed to cover the upper and lower surfaces of the resistive layer 213a and is made of an insulating material.

The absorber layer 30 includes an absorption layer 219a that absorbs infrared rays and an absorption protective layer 219b that electrically insulates the absorption layer 219a or protects it from the outside. The absorption layer 219a is implemented in a form in contact with the top surface of the resistor layer 31, and the absorption protection layer 219b is formed in a form to protect the top surface of the absorption layer 219a. The absorption protective layer 219b is formed of an insulating material.

The connection bridge layer 32 includes a connection bridge portion 211a electrically connecting the resistance layer 213a and the support pillar 214 and a connection bridge metal layer 211b. In addition, the connection bridge layer 32 may include an insulator 212 to protect the connection bridge portion 211a and the connection bridge metal layer 211b. Here, the connecting bridge portion 211a and the connecting bridge metal layer 211b are made of a metal having high conductivity and low thermal conductivity, such as titanium, chromium, nickel-chromium, or titanium alloy, or a conductive ceramic material.

The support pillar 214 is formed between the connection bridge layer 32 connected to the resistive layer 213a and the reflective pad 215 .

The support pillar 214 has one side connected to the reflective pad 215 and the other side connected to the connection bridge layer 32 . The support pillar 214 is formed of one metal of titanium (Ti), nickel (Ni), copper (Cu), and aluminum (Al) or an alloy of at least one metal.

In the reactant cell 210 of FIG. 6 , a thermally isolated structure is formed by removing the sacrificial layer, which is the thermal conductive layer 218 .

7 is a view for explaining a manufacturing process of a reactant cell according to an embodiment of the present invention.

(a) of FIG. 7 shows step S710 of forming the reflective pad 215 on the sensor substrate 217 .

In step S710 , a reflective material is deposited on the sensor substrate 217 and a partial region is etched to form the reflective pad 215 . Here, the reflective pad 215 may be formed using a metal material such as aluminum, titanium, or gold having high infrared reflectivity.

The reflective pad 215 is formed to be electrically connected to the signal layer 216 of the sensor substrate 217 and may be formed to re-absorb transmitted infrared rays.

(b) of FIG. 7 shows step S720 of forming the thermal conduction layer 218 and the resistor layer on the sensor substrate 217 and the reflective pad 215 .

In step S720 , a thermal conductive layer 218 is preferentially deposited on the sensor substrate 217 and the reflective pad 215 , and a resistor layer is deposited on the thermal conductive layer 218 . Specifically, in step S720, the first passivation layer 213b, the resistive layer 213a, and the second passivation layer 213b are sequentially deposited on the heat conduction layer 218, and the resistive layer 213a and the second passivation layer 213a are deposited. Both ends of the protective layer 213b are etched.

The heat conduction layer 218 formed in step S720 is formed for a λ/4 spacing structure having a maximum light absorption efficiency. In addition, the resistance layer 213a is formed for an operation in which resistance is changed according to temperature change.

(c) of FIG. 7 shows a step S730 of forming a cavity for forming the support pillar 214 .

Step S730 forms a cavity for electrically connecting the signal layer 216 of the sensor substrate 217 and forming the support pillar 214 supporting the structure.

In step S730 , holes are formed at both ends of the second passivation layer 213b and the thermal conduction layer 218 through hole patterning and etching. Here, etching may be etching using Cl and F-groups.

(d) of FIG. 7 shows step S740 of forming the support pillar 214 and the connection bridge layer 32 .

In step S740, the signal circuit board and the electrical connection and the support pillar 214 for supporting the structure are deposited in the previously formed cavity.

The support pillar 214 may be formed of one metal among titanium (Ti), nickel (Ni), copper (Cu), and aluminum (Al), or an alloy in which at least one metal is mixed.

After the support pillars 214 are formed, a connection bridge layer 32 for thermal isolation of the structure is formed in step S740. Here, the connection bridge layer 32 is formed using a material with low thermal conductivity.

The connection bridge layer 32 includes a connection bridge part 211a for transmitting an electrical signal by connecting the signal layer 216 and the resistor 213a, and a connection bridge metal layer 211b connected to the connection bridge part 211a. formed in the form In addition, the connection bridge layer 32 includes an insulator 212 to protect the connection bridge portion 211a and the connection bridge metal layer 211b.

(e) of FIG. 7 shows step S750 of forming the absorption layer 219 .

Step S750 forms the absorber layer 30 on the resistor layer 31 .

The absorber layer 30 includes an absorption layer 219a that absorbs infrared rays and an absorption protective layer 219b that electrically insulates the absorption layer 219a or protects it from the outside. The absorption layer 219a is implemented in a form in contact with the top surface of the resistor layer 31, and the absorption protection layer 219b is formed in a form to protect the top surface of the absorption layer 219a. The absorption protective layer 219b is formed of an insulating material.

7(f) shows step S760 of removing the thermal conductive layer 218 to form a structure for thermal isolation.

In step S760, a structure for thermal isolation is formed by removing the sacrificial layer (polyimide), which is the thermal conductive layer 218. Step S760 includes a support pillar 214 that separates the bridge layer 32 and the absorber layer 30 from the sensor substrate 217 by about λ/4 through the removal of the thermal conductive layer 218 to have a maximum absorption rate. In the form of forming a structure for thermal isolation.

In FIG. 7, it is described that each step is sequentially executed, but is not necessarily limited thereto. In other words, since it will be applicable to changing and executing the steps described in FIG. 7 or executing one or more steps in parallel, FIG. 7 is not limited to a time-series sequence.

8 is a circuit diagram illustrating a detection circuit in which a reactant cell and a reference cell are connected to a signal acquisition circuit according to an embodiment of the present invention.

The reactant cell 210 is connected to the ground with a transistor 240 that determines the bias voltage (Va), and the reference cell 220 is connected to another transistor 250 that determines the bias voltage (Vb) and a power line. .

The two transistors 240 and 250 are connected to the negative terminal of the operational amplifier, and this terminal is connected to a capacitor, which is connected to the output of the operational amplifier.

The positive terminal of the operational amplifier is connected to the reference voltage. The basic current (Ia) generated in the reactant cell 210 is canceled by the offset current (Ib) generated in the reference cell.

If the resistance of the reactant cell 210 is changed by the incident infrared rays, the current component flowing through the reactant cell 210 changes, and only this modulated current (ΔI) is integrated by the capacitor 260 to appear as a signal component. .

9 is an exemplary diagram illustrating the output of an infrared image using a bolometer infrared sensor according to an embodiment of the present invention.

9(a) shows an infrared image output by a general bolometer infrared sensor.

9(b) shows image noise 900 generated when sunlight is incident on a reference cell of a general bolometer infrared sensor.

When the blocking layer is formed on the reference cell of the bolometer infrared sensor as in the embodiment of the present invention, an infrared image without image noise can be output as shown in FIG. 9(c).

The above description is only illustrative of the technical idea of the embodiment of the present invention, and those skilled in the art to which the embodiment of the present invention pertains may make various modifications and modifications within the scope not departing from the essential characteristics of the embodiment of the present invention. transformation will be possible. Therefore, the embodiments of the present invention are not intended to limit the technical idea of the embodiment of the present invention, but to explain, and the scope of the technical idea of the embodiment of the present invention is not limited by these examples. The protection scope of the embodiments of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the embodiments of the present invention.

10: infrared detector 100: infrared window
200: infrared sensor 300: feed through
210: reactant cell
31: absorber layer 32: connection bridge layer
214: support pillar 215: reflective pad
217: sensor board
220: reference cell
21: resistor layer 22: connection bridge layer
224: support pillar 225: contact pad
227: sensor substrate 228: thermal conduction layer
229: barrier layer

Claims (10)

A method for manufacturing a bolometer infrared sensor for minimizing output change by a high-temperature target,
forming a contact pad on a sensor substrate including a signal layer for transmitting electrical signals of a signal acquisition circuit;
forming a thermal conduction layer and a resistor layer on the contact pad;
forming a cavity at both ends of the thermal conduction layer and the resistor layer;
forming a support pillar in the cavity and forming a blocking film layer on the resistor layer; and
Forming a connection bridge layer such that one side is connected to the support pillar and the other side is connected to the resistor layer.
Method for manufacturing a bolometer infrared sensor comprising a. According to claim 1,
Forming the support pillar and the blocking film layer,
A method of manufacturing a bolometer infrared sensor, characterized in that the support pillar is formed such that one side is connected to the contact pad and the other side is connected to the connection bridge layer. According to claim 1,
Forming the support pillar and the blocking film layer,
The manufacturing method of the bolometer infrared sensor, characterized in that the blocking film layer is formed of the same material as the material of the support pillar, and the support pillar and the blocking film layer are formed at the same time. According to claim 3,
The barrier layer is
A method of manufacturing a bolometer infrared sensor, characterized in that it is formed of one metal of titanium (Ti), nickel (Ni), copper (Cu) and aluminum (Al) or an alloy of a mixture of at least one metal. According to claim 1,
Forming the support pillar and the blocking film layer,
A method for manufacturing a bolometer infrared sensor, characterized in that the blocking film layer having a square or mesh shape is formed on the upper side of the resistor layer. According to claim 5,
Forming the support pillar and the blocking film layer,
In the case of forming a rectangular blocking film layer, the rectangular blocking film layer is formed to a thickness of 0.1 μm to 1 μm, and a thickness capable of reflecting infrared rays in the long wavelength infrared (LWIR) wavelength band of at least 8 to 14 um Method for manufacturing a bolometer infrared sensor, characterized in that formed by. According to claim 5,
Forming the support pillar and the blocking film layer,
In the case of forming a mesh-shaped blocking film layer, each mesh-shaped lattice shape is formed to a thickness of 0.1 μm to 1 μm. According to claim 7,
Forming the support pillar and the blocking film layer,
The mesh-shaped blocking film layer is formed in a structure in which a plurality of lattices are arranged, the width of the lattice pattern is formed to be 0.18 μm to 4 μm, and the width of the space formed between the lattice is formed to be 0.18 μm to 4 μm. Method for manufacturing a characterized bolometer infrared sensor. According to claim 1,
Forming the support pillar and the blocking film layer,
The blocking film such that the upper surface of the blocking film layer is at the same height as the upper surface of the insulating layer surrounding one end of the support pillar or 0.1 μm to 1 μm higher than the upper surface of the insulating layer surrounding one end of the supporting pillar. A method for manufacturing a bolometer infrared sensor, characterized by forming a layer. According to claim 1,
Forming the blocking film layer,
Forming the support pillar in a form including a groove in the center of the pillar,
The manufacturing method of the bolometer infrared sensor, characterized in that the concave portion is formed such that the thickness of the support pillar is 0.1 μm to 1 μm.

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