Microbolometer systems and methods

Abstract

Microbolometer systems and methods are provided herein. For example, an infrared imaging device includes a substrate having contacts and a surface. The surface defines a plane. The infrared imaging device also includes an array of microbolometers coupled to the substrate. Each microbolometer in the array includes a cross-section having a first section, a second section, and a third section, wherein the second section is substantially parallel to the first section, and the third section connects the first section and the second section.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 816,889, filed on March 11, 2019, entitled “Vertical Microbolometer Contact System and Method,” the entire contents of which are hereby incorporated by reference.

[0003] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 907,548, filed September 27, 2019, entitled “Microbolometer Systems and Methods,” the entire contents of which are hereby incorporated by reference.

[0004] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 907,555, filed on September 28, 2019, entitled “Microbolometer Systems and Methods,” the entire contents of which are hereby incorporated by reference.

[0005] This application is related to U.S. patent application Ser. No. 16 / 226,580, filed on December 19, 2018, entitled “Vertical Microbolometer Contact System and Method,” which is a part of U.S. patent application Ser. No. 15 / 396,100, filed on December 30, 2016, entitled “Vertical Microbolometer Contact System and Method,” which is a continuation of International Patent Application No. PCT / US2015 / 039138, filed on July 2, 2015, entitled “Vertical Microbolometer Contact System and Method,” which claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 020,747, filed on July 3, 2014, entitled “Vertical Microbolometer Contact System and Method,” all of which are hereby incorporated by reference in their entirety. Technical Field

[0006] One or more embodiments of the present invention relate generally to infrared cameras, and more particularly to microbolometer contact systems and methods, such as vertical leg contacts for a microbolometer focal plane array. Background Art

[0007] A microbolometer is one embodiment of a type of infrared detector that can be used in infrared imaging devices (e.g., infrared cameras). For example, microbolometers are typically fabricated on a monolithic silicon substrate to form an infrared (image) detector array, with each microbolometer of the infrared detector array acting as a pixel to produce a two-dimensional image. The resistance change of each microbolometer is converted into a time-multiplexed electrical signal by a circuit called a readout integrated circuit (ROIC). The combination of an ROIC and an infrared detector array (e.g., a microbolometer array) is typically referred to as a focal plane array (FPA) or infrared FPA (IRFPA). Additional details about FPAs and microbolometers can be found in U.S. Patent Nos. 5,756,999, 6,028,309, 6,812,465, and 7,034,301, the entire contents of which are incorporated herein by reference.

[0008] Each microbolometer in the array is typically connected to one or more contacts extending vertically downward from the array to the ROIC. The contacts can be used to provide a reference voltage for the microbolometer and / or provide a signal path from the microbolometer to the ROIC. The microbolometer typically includes a photosensitive portion formed of a resistive material suspended from a bridge. The resistive material is connected to the contacts via legs extending from the bridge to the contacts. The legs are attached to the resistive material via the contacts.

[0009] One of the challenges in designing efficient microbolometers is improving the ratio of the photosensitive area, or active pixel area, to the total area of ​​the array, sometimes referred to as the array's fill factor. Each microbolometer's support leg can occupy a significant portion of the array's area, thus limiting the array's fill factor. Therefore, it would be desirable to reduce the area occupied by the legs. However, to maintain device performance, the width and length of each leg should be proportional to the area of ​​each pixel. Therefore, reducing the leg area and improving the fill factor is difficult. Consequently, there is a need for improved techniques for implementing leg supports, such as in microbolometer-based focal plane arrays. Summary of the Invention

[0010] According to one or more embodiments, systems and methods are disclosed that relate to microbolometer legs for infrared detectors. For example, according to one embodiment of the present invention, vertical legs (e.g., for infrared detectors within a focal plane array) are disclosed that may be more area-efficient than conventional legs that extend substantially horizontally along the plane of the infrared detector. According to one or more embodiments, the leg systems and methods disclosed herein may provide advantages over conventional leg approaches, particularly as semiconductor processing technology transitions to smaller dimensions.

[0011] According to one embodiment, an infrared imaging device includes a substrate including a plurality of contacts and a surface. The surface defines a plane. The infrared imaging device also includes a microbolometer array coupled to the substrate, wherein the microbolometer array includes a plurality of microbolometers. Each microbolometer includes a bridge and a leg structure coupled to the bridge and one of the plurality of contacts. The leg structure includes a metal layer having: a first dimension extending in a first direction, the first dimension being substantially perpendicular to the plane; a second dimension extending in a second direction, the second dimension being substantially parallel to the plane, wherein the first dimension is greater than the second dimension. The leg structure further includes a first layer formed on a first sidewall of the metal layer. The leg structure also includes a second layer formed on a second sidewall of the metal layer and a second side of the metal layer. The first sidewall is opposite to the second sidewall. The first side is opposite to the second side.

[0012] According to one embodiment, an infrared imaging device includes a microbolometer array comprising a plurality of microbolometers. Each microbolometer includes a bridge. The bridge includes a first portion including a resistive layer configured to capture infrared radiation and a second portion having a plurality of perforations defined therein.

[0013] According to one embodiment, an infrared imaging device includes an array of microbolometers, each microbolometer having a bridge coupled to a contact via at least one vertical bolometer leg. The legs and bridge of the microbolometer array can be suspended above a readout integrated circuit of the microbolometer array. The vertical bolometer legs can be formed using spacer deposition and etching processes that form at least a portion of the vertical bolometer legs on the sidewalls of an opening in a sacrificial layer, which is then removed to release the bolometer legs.

[0014] According to various embodiments, the vertical bolometer legs can extend along a path that is arranged parallel to a plane defined by the microbolometer bridge and / or a plane defined by a substrate surface of the device (e.g., a readout integrated circuit substrate), and can have an extended dimension that extends in a direction perpendicular to the plane of the path, the substrate surface, and / or the plane of the bridge. In this way, the area of ​​the bolometer legs, which would otherwise occupy a relatively large portion of the surface area of ​​the microbolometer array, can be reduced without reducing the area of ​​the bolometer legs.

[0015] Depending on the implementation, the leg structure may or may not be encapsulated in an insulating layer, such as silicon dioxide or silicon nitride. The leg structure may be formed from multiple layers of insulating material to optimize performance. The leg conductive layer may be fully or partially encapsulated by an insulating layer, or may not contain any insulating layer. The leg conductive layer may be a homogeneous film of a single material type, or it may be a multilayer conductive layer formed, for example, from several deposits.

[0016] According to one embodiment, an infrared imaging device includes a substrate having a plurality of contacts and a surface. The surface defines a plane. The infrared imaging device also includes a microbolometer array coupled to the substrate, wherein the microbolometer array includes a plurality of microbolometers. Each microbolometer includes a bridge and a leg structure coupled to the bridge and one of the plurality of contacts. The leg structure includes a cross-section having a first portion, a second portion substantially parallel to the first portion, and a third portion connecting the first portion and the second portion. In some aspects, the bridge has a first portion and a second portion. The first portion includes a resistive layer configured to capture infrared radiation. The second portion includes a plurality of perforations defined therein.

[0017] According to one embodiment, a method for forming an infrared imaging device includes forming a bridge on a sacrificial layer. The method further includes forming an opening in the sacrificial layer. The method further includes disposing a contact metal layer on the sidewalls of the opening. The method also includes forming a leg structure coupled to the bridge and the contact metal layer. The leg structure has a cross-section having a first portion, a second portion substantially parallel to the first portion, and a third portion connecting the first portion and the second portion. The method also includes removing the sacrificial layer to suspend the bridge and the leg structure above a substrate of the infrared imaging device. The contact metal layer is coupled to the substrate.

[0018] According to one embodiment, an infrared imaging device includes a microbolometer array having a plurality of microbolometers. Each microbolometer includes a microbolometer bridge. The microbolometer bridge includes a first portion comprising a resistive layer configured to capture infrared radiation; and a second portion having a plurality of perforations defined therein. In some aspects, the infrared imaging device further includes a substrate comprising a plurality of contacts and a surface. The surface defines a plane. Each microbolometer further includes a leg structure coupled to the microbolometer bridge and one of the plurality of contacts. The leg structure includes a cross-section having a first section, a second section, and a third section, the second section being substantially parallel to the first section, and the third section connecting the first section and the second section.

[0019] According to one embodiment, a method of forming an infrared imaging device includes forming a bridge structure, forming a leg structure, and forming a plurality of perforations in the bridge structure to obtain a microbolometer bridge.

[0020] According to one embodiment, a method for forming an infrared imaging device includes forming a bridge on a sacrificial layer, wherein the bridge includes a first portion having a resistive layer configured to capture infrared radiation and a second portion having a plurality of perforations formed therein. The method also includes forming an opening in the sacrificial layer. The method further includes disposing a contact metal layer on sidewalls of the opening. The method further includes forming a leg structure coupled to the bridge and the contact metal layer. The method also includes removing the sacrificial layer and suspending the bridge and leg structure above a substrate of the infrared imaging device, wherein the contact metal layer is coupled to the substrate.

[0021] The scope of the present invention is defined by the claims, which are incorporated herein by reference. Those skilled in the art will gain a more complete understanding of the embodiments of the present invention and realize additional advantages thereof by considering the following detailed description of one or more embodiments. Reference will be made to the accompanying drawings, which will first be briefly described. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A block diagram illustrating an infrared camera is shown in accordance with one or more embodiments.

[0023] Figure 2 A block diagram illustrating an example of an infrared camera is shown in accordance with one or more implementations.

[0024] Figure 3 A diagram illustrating the physical layout of a microbolometer of an array of microbolometers having vertical legs according to one embodiment.

[0025] 4A and 4B illustrate a top view and a cross-sectional side view, respectively, of a conventional horizontal leg for a microbolometer.

[0026] Figure 5A and 5B Shown are a top view and a cross-sectional side view, respectively, of a vertical leg (eg, a leg used to couple an infrared detector element to a contact) according to one embodiment.

[0027] Figures 6A to 6F A method for manufacturing a vertical leg (e.g., for Figure 3 Schematic diagram of the processing of the vertical support leg).

[0028] Figures 7A to 7FA method for manufacturing a vertical leg (e.g., for Figure 3 Another machining overview of the vertical legs.

[0029] Figures 8A to 8C A method for manufacturing a vertical leg (e.g., for Figure 3 Another processing overview of the vertical support leg).

[0030] Figure 9 A cross-sectional side view of a portion of a focal plane array having vertical legs formed below the surface of the array near vertical contacts between an infrared detector array and a readout integrated circuit is shown in accordance with one embodiment.

[0031] Figure 10 A cross-sectional side view of a portion of a focal plane array having vertical legs formed below the surface of the array near a sensor of the array is shown according to one embodiment.

[0032] Figure 11 A cross-sectional side view of a portion of a focal plane array having vertical legs formed below the array surface near vertical contacts between an infrared detector array and a readout integrated circuit is shown in accordance with one embodiment.

[0033] Figure 12 A cross-sectional side view of a portion of a focal plane array having vertical legs formed below the surface of the array near a sensor of the array is shown according to one embodiment.

[0034] Figures 13A to 13Q Vertical legs (e.g. Figure 5A and 5B Various arrangements of vertical legs).

[0035] Figure 14 A cross-sectional side view of a portion of a focal plane array having vertical legs formed at or above a surface of the array near vertical contacts between an infrared detector array and a readout integrated circuit is shown in accordance with one embodiment.

[0036] Figure 15 A cross-sectional side view of a portion of a focal plane array having vertical legs formed above the surface of the array near a sensor of the array is shown according to one embodiment.

[0037] Figure 16 A top view of a curved portion of a vertical leg according to one embodiment is shown, for example, Figure 3 near the bend of the vertical leg.

[0038] Figure 17 According to one embodiment, Figure 16 A cross-sectional view of an example arrangement of vertical legs.

[0039] Figure 18 According to one embodiment, Figure 16 A cross-sectional view of another example arrangement of vertical legs.

[0040] Figure 19 A cross-sectional view of a portion of a focal plane array having legs (eg, legs for infrared detectors) formed at least partially beneath a bridge portion of the infrared detectors is shown according to one embodiment.

[0041] Figure 20 A method for manufacturing a vertical leg (e.g. Figure 3 vertical legs).

[0042] Figure 21 A method for manufacturing a vertical leg (such as Figure 3 Another flow chart of the vertical legs).

[0043] Figure 22 Another flow chart for manufacturing a vertical leg according to one embodiment is shown, for example Figure 3 Vertical legs.

[0044] Figures 23A to 23F A method for fabricating vertical legs (e.g., for Figure 3 Schematic diagram of the processing of the vertical support leg).

[0045] Figure 24 A cross-sectional view of a portion of a focal plane array having legs (eg, legs for infrared detectors) formed at least partially beneath a bridge portion of the infrared detectors is shown according to one embodiment.

[0046] Figure 25 A flow chart is shown for fabricating a focal plane array having legs (eg, legs for infrared detectors) formed at least partially beneath a bridge portion of the infrared detectors, according to one embodiment.

[0047] Figure 26 Shown is a top view of the bolometer.

[0048] Figure 27 Shown Figure 26 Cross-section of a bolometer leg.

[0049] Figure 28The rigidity provided by the vertical members is shown.

[0050] Figure 29 A top view of a bolometer with vertical legs is shown according to one embodiment.

[0051] Figure 30A According to one embodiment, Figure 29 Cross-section of a bolometer leg.

[0052] Figure 30B According to one embodiment, Figure 30A The height of the legs is smaller than the cross-section of the legs.

[0053] Figure 31 Shown is a cross section of a leg of a bolometer according to one embodiment.

[0054] Figure 32 A top view of a bolometer with a bridge, vertical legs, and contacts is shown according to one embodiment, wherein the bolometer is manufactured using an oxide method.

[0055] Figure 33 According to one embodiment, Figure 32 Cross section of the leg.

[0056] Figure 34 A top view of a bolometer having a bridge, vertical legs, and contacts is shown according to one embodiment, wherein the bolometer is fabricated using a directed self-assembly method.

[0057] Figure 35 According to one embodiment, Figure 34 Cross section of the leg.

[0058] Figures 36A to 36N A cross-sectional side view is shown relating to an example process for forming a bolometer according to one embodiment.

[0059] Figure 37 According to one embodiment, Figure 36N The cross-sectional side view corresponds to the top view.

[0060] Figures 38A to 38D A cross-sectional side view is shown relating to an example process of forming contacts according to one embodiment.

[0061] Figures 39A to 39D A cross-sectional side view is shown relating to an example process for forming legs after forming contacts to a readout circuit wafer according to one embodiment.

[0062] Figure 39E Shown Figure 39D An enlarged view of a portion of the structure.

[0063] Figure 40 According to one embodiment, the corresponding Figure 39D A top view of a cross-sectional side view.

[0064] Figures 41A to 41T A cross-sectional side view is shown relating to an example process of forming a bolometer according to one embodiment.

[0065] Figure 42 According to one embodiment, Figure 41T The cross-sectional side view corresponds to the top view.

[0066] Figure 43A and 43B A diagram related to a bolometer is shown according to one embodiment.

[0067] Figures 44A to 44E Various views are shown relating to another bolometer according to one embodiment.

[0068] Figures 45A to 45F A cross-sectional side view is shown relating to an example process for forming a bolometer according to one embodiment.

[0069] Figures 46A to 46F According to one embodiment, Figures 45A to 45F An overhead view of the example process.

[0070] Figure 47A and 47B Shown Figure 45C Magnified view of the identified portion.

[0071] Figure 48 is a flow chart of illustrative operations that may be performed to form a bolometer according to one embodiment.

[0072] Figure 49 is a perspective view of a bolometer according to one embodiment.

[0073] Figure 50 According to one embodiment, Figure 49 Top view of the thermal radiation meter.

[0074] Figures 51A to 51C Other examples of bolometers according to one or more implementations are shown.

[0075] Figure 52 A cross-sectional side view of a portion of a bolometer is shown according to one embodiment.

[0076] Figure 53A cross-sectional side view of a portion of a bolometer having a through-hole defined therein is shown according to one embodiment.

[0077] Figure 54 is a flow chart of illustrative operations performed to form a bolometer having a through-hole defined in a bolometer bridge according to one embodiment.

[0078] Figures 55A to 55D A cross-sectional side view is shown relating to an example process for forming a bolometer according to one embodiment.

[0079] Figure 56 According to one embodiment, Figure 55D The cross-sectional side view corresponds to the top view.

[0080] Embodiments of the present invention and their advantages may be best understood by referring to the following detailed description.It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures. DETAILED DESCRIPTION

[0081] Disclosed herein are systems and methods that, according to one or more embodiments, provide vertically oriented legs for infrared detectors. For example, according to one embodiment, vertical bolometer legs are disclosed, such as for use with microbolometers within a focal plane array. As an example, Figure 1 A block diagram is shown illustrating a system 100 (e.g., an infrared camera, including any type of infrared imaging system) for image capture and processing according to one or more embodiments. In one embodiment, system 100 includes an image capture component 102, a processing component 104, a control component 106, a storage component 108, and a display component 110. Optionally, system 100 may include a sensing component 112.

[0082] System 100 can represent, for example, an infrared imaging device (e.g., an infrared camera) for capturing and processing images (e.g., video images of scene 101). System 100 can represent any type of infrared camera that employs an infrared detector with contacts and can be implemented as disclosed herein. System 100 can include a portable device and can be incorporated into, for example, a vehicle (e.g., an automobile or other type of land vehicle, aircraft, or spacecraft) or a non-mobile device that needs to store and / or display infrared images, or can include a distributed network system (e.g., processing component 104 is remote from and controls image capture component 102 via a network).

[0083] In various embodiments, processing component 104 may include any type of processor or logic device (e.g., a programmable logic device (PLD) configured to perform processing functions). Processing component 104 may be adapted to interface and communicate with components 102, 106, 108, and 110 to perform method and processing steps and / or operations (e.g., controlling bias and other functions (e.g., values ​​of elements such as variable resistors and current sources, switch settings for biasing and timing, and other parameters)) and other conventional system processing functions as understood by those skilled in the art.

[0084] In one embodiment, storage component 108 includes one or more storage devices suitable for storing data and information (including, for example, infrared data and information). Storage component 108 may include one or more storage devices of various types, including volatile and non-volatile storage devices, including computer-readable media (portable or fixed). Processing component 104 may be adapted to execute software stored in storage component 108 to perform the method and process steps and / or operations described herein.

[0085] Image capture component 102, in one embodiment, includes one or more infrared sensors (e.g., any type of multi-pixel infrared detector, such as a focal plane array having one or more vertical legs as disclosed herein) for capturing infrared image data (e.g., still image data and / or video data) representing an image (e.g., scene 101). In one embodiment, the infrared sensor of image capture component 102 provides for representing (e.g., converting) the captured image data into digital data (e.g., via an analog-to-digital converter included as part of the infrared sensor or separate from the infrared sensor as part of system 100). In one or more embodiments, image capture component 102 may further represent or include a lens, a shutter, and / or other related components for capturing infrared image data in conjunction with a vacuum packaging assembly. Image capture component 102 may further include a temperature sensor (or the temperature sensor may be distributed within system 100) to provide temperature information regarding the operating temperature of image capture component 102 to processing component 104.

[0086] In one aspect, infrared image data (e.g., infrared video data) may include non-uniform data (e.g., real image data) of an image (e.g., scene 101). Processing component 104 may be adapted to process the infrared image data (e.g., provide processed image data), store the infrared image data in storage component 108, and / or retrieve stored infrared image data from storage component 108. For example, processing component 104 may be adapted to process infrared image data stored in storage component 108 to provide processed image data and information (e.g., captured and / or processed infrared image data).

[0087] In one embodiment, the control unit 106 includes a user input and / or interface device, such as a rotatable knob (e.g., a potentiometer), a button, a slide bar, a keyboard, etc., which is suitable for generating user input control signals. The processing unit 104 can be suitable for sensing control input signals from the user through the control unit 106 and responding to any sensed control input signals received therefrom. The processing unit 104 can be suitable for interpreting such control input signals as parameter values, as generally understood by those skilled in the art. In one embodiment, the control unit 106 can include a control unit (e.g., a wired or wireless handheld control unit) having buttons suitable for connecting to a user interface and receiving user input control values. In one embodiment, the buttons of the control unit can be used to control various functions of the system 100, such as autofocus, menu activation and selection, field of view, brightness, contrast, noise filtering, high-pass filtering, low-pass filtering and / or various other functions understood by those skilled in the art.

[0088] In one embodiment, the display component 110 includes an image display device (e.g., a liquid crystal display (LCD) or various other types of generally known video displays or monitors). The processing component 104 can be adapted to display image data and information on the display component 110. The processing component 104 can be adapted to retrieve image data and information from the storage component 108 and display any retrieved image data and information on the display component 110. The display component 110 can include display electronics that can be utilized by the processing component 104 to display image data and information (e.g., infrared images). The display component 110 can be adapted to receive image data and information directly from the image capture component 102 via the processing component 104, or the image data and information can be transmitted from the storage component 108 via the processing component 104.

[0089] The optional sensing component 112, in one embodiment, includes one or more sensors of various types, depending on the application or implementation requirements, as will be understood by those skilled in the art. The sensors of the optional sensing component 112 provide data and / or information to at least the processing component 104. In one aspect, the processing component 104 can be adapted to communicate with the sensing component 112 (e.g., by receiving sensor information from the sensing component 112) and with the image capture component 102 (e.g., by receiving data and information from the image capture component 102 and providing and / or receiving commands, controls, and / or other information to one or more other components of the system 100).

[0090] In various embodiments, the sensing component 112 can provide information about environmental conditions, such as external temperature, lighting conditions (e.g., daytime, nighttime, dusk, and / or dawn), humidity, specific weather conditions (e.g., sun, rain, and / or snow), distance (e.g., laser rangefinder), and / or whether a tunnel or other type of enclosure has been entered or exited. The sensing component 112 can represent conventional sensors commonly known to those skilled in the art for monitoring various conditions (e.g., environmental conditions) that may affect the data provided by the image capture component 102 (e.g., the appearance of the image).

[0091] In some embodiments, the optional sensing component 112 (e.g., one or more of the sensors) may include devices that communicate information via wired and / or wireless communications to the processing component 104. For example, the optional sensing component 112 may be adapted to receive information from a satellite, via local broadcast (e.g., radio frequency (RF)) transmissions, via a mobile or cellular network, and / or via information beacons in infrastructure (e.g., transportation or highway information beacon infrastructure), or various other wired and / or wireless technologies.

[0092] In various embodiments, the components of system 100 may be combined and / or implemented or not implemented as needed or depending on the application or requirements, with system 100 representing various functional blocks of a related system. In one embodiment, processing component 104 may be combined with storage component 108, image capture component 102, display component 110, and / or optional sensor component 112. In another embodiment, processing component 104 may be combined with image capture component 102, with only certain functions of processing component 104 being performed by circuitry within image capture component 102 (e.g., a processor, microprocessor, logic device, microcontroller, etc.). Furthermore, various components of system 100 may be remote from one another (e.g., image capture component 102 may include a remote sensor, with processing component 104 representing a computer that may or may not be in communication with image capture component 102).

[0093] Figure 2 FIG. 1 is a block diagram illustrating a specific embodiment of an infrared camera 200 according to one or more embodiments. The infrared camera 200 may represent a system 100 ( Figure 1 ) is a specific embodiment, which will be understood by those skilled in the art.

[0094] Infrared camera 200 (e.g., a microbolometer readout integrated circuit with bias correction circuitry and interface system electronics) includes a readout integrated circuit (ROIC) 202, which may include an array of microbolometer cells having one or more contacts coupled to a microbolometer bridge via vertical legs as disclosed herein, control circuitry, timing circuitry, bias circuitry, row and column addressing circuitry, column amplifiers, and associated electronics to provide output signals digitized by analog-to-digital (A / D) converter 204. A / D converter 204 may be part of ROIC 202 or separate therefrom.

[0095] The output signal from A / D converter 204 is conditioned by non-uniformity correction circuitry (NUC) 206, which applies temperature-dependent compensation, as will be understood by those skilled in the art. After processing by NUC 206, the output signal is stored in frame memory 208. The data in frame memory 208 is then available to image display electronics 210 and data processor 214, which may also have data processor memory 212. Timing generator 216 provides system timing.

[0096] Data processor 214 generates offset correction data words, which are loaded into correction coefficient memory 218. Data register loading circuit 220 provides an interface for loading the correction data into ROIC 202. In this manner, variable circuits (e.g., variable resistors that control voltage levels, biases, frame timing, circuit component values, digital-to-analog converters, bias circuits, etc.) are controlled by data processor 214 so that the output signal of ROIC 202 is uniform over a wide temperature range.

[0097] It should be understood that the various functional blocks of infrared camera 200 may be combined or not required, depending on the specific application and specific requirements. For example, data processor 214 may perform various functions of NUC 206, while various memory blocks (such as correction coefficient memory 218 and frame memory 208) may be combined as needed.

[0098] Figure 3 A physical layout diagram of a microbolometer 300 according to one embodiment of the present invention is shown. The microbolometer 300 includes a bridge portion 302 having a light sensor 304 and bridge contacts 306 coupling the sensor 304 to first ends of legs 308. The legs 308 each couple the sensor 304 to one of the contacts 310.

[0099] Each contact 310 can connect one or more associated microbolometers 300 to associated readout circuitry of a readout integrated circuit (ROIC, not shown). For example, a first contact 310 can be used to provide a reference or bias voltage to the microbolometer, and a second contact 310 can be used to provide a signal path from the microbolometer to the ROIC, through which a signal corresponding to infrared light absorbed by the microbolometer can be read. Further description of the ROIC and microbolometer circuitry can be found in U.S. Patent No. 6,028,309, which is hereby incorporated by reference in its entirety for all purposes.

[0100] The sensor 304 may be arranged to convert incident light (e.g., infrared light) into a detectable electrical signal. The conversion is based on a change in the sensor's electrical properties (e.g., resistivity) due to a change in the sensor's temperature when the light is incident. According to one embodiment, the sensor 304 may include a resistive material, which may be made of a high temperature coefficient of resistivity (TCR) material (e.g., vanadium oxide (VO x ), titanium oxide (TiO x The resistive material may be suspended above the ROIC on the bridge 302 and connected to its contacts 310 via legs 308.

[0101] According to various embodiments, each contact 310 may be connected to a portion of a leg 308 that bends downward toward the ROIC (e.g., the contact 310 may be formed on a substrate such as the ROIC, and the leg 308 may include a portion extending from a first height above the substrate, such as the height of the bridge, downward to a non-perpendicular angle to the substrate contact) and / or each contact 310 may include a portion extending downward from the leg 308 to the surface of the ROIC (e.g., at a position substantially perpendicular to the substrate). Figure 3 The legs 308 may be formed from one or more layers of a conductive material, such as titanium, nickel chromium, and / or other suitable conductive materials.

[0102] In order to provide legs 308 with a width and length sufficient to provide suitable performance for microbolometer 300 without reducing the fill factor of a microbolometer array including microbolometer 300, legs 308 may be vertically oriented legs, as shown, along Figure 3 in the XY plane and / or parallel to Figure 3 The path of the XY plane extends and has a direction parallel to the Figure 3 The legs 308 may include a curved portion 312. The curved portion 312 may have additional electrical connections and / or support structures, as described in further detail below.

[0103] Such as Figure 3The plane of the xy plane may be defined by a bridge of the microbolometer (e.g., the bridge may comprise a planar sensor layer such as a resistive layer defining a plane, or may define a plane passing through multiple bridges in the microbolometer array) or by a surface of a substrate (e.g., an ROIC substrate) to which the microbolometer array is coupled and disposed.

[0104] Figures 4A and 4B illustrate, respectively, a top view and a cross-sectional view of a conventional microbolometer 400 having a horizontally oriented leg 406. As shown in the top view of Figure 4A, the bridge 402 of the microbolometer 400 is connected to the horizontally oriented leg 406 via a bridge contact 404, with the leg having an extension dimension of width WP extending within the xy plane of Figure 4A. In the cross-sectional view of Figure 4B, taken along line AA of Figure 4A, it can be more easily seen that the contact 404, leg 406, and resistive material 403 of the microbolometer 400 all extend along the same plane or parallel planes to the xy plane of Figure 4B.

[0105] on the contrary, Figure 5A and 5B A top view and a cross-sectional view are shown, respectively, of a microbolometer 500 according to an embodiment of the present disclosure, the embodiment including vertical legs 308. As shown, the vertical legs 308 are Figure 5A and 5B The XY plane of the support leg 308 may have a width W. By allowing the support leg 308 to be perpendicular to the XY plane (e.g., Figure 5A and 5B The vertical leg 308 extends in a direction parallel to the Z direction of the ROIC, and the width W can be relatively smaller than the width WP of a conventional microbolometer leg without sacrificing the overall volume of the leg, so that the vertical leg 308 is perpendicular to the plane defined by the bridge 302 (e.g., by the resistive material 501 of the bridge 302, by the bridge contacts 306, and / or by the bolometer bridge array formed at a common height above the ROIC) and / or by the plane defined by the substrate surface above which the bridge is formed.

[0106] As shown, according to one embodiment, the vertical leg 308 may include a conductive (e.g., metal) portion 506 and, if desired, an insulating material 508 on one or more sides of the conductive portion. However, this is merely illustrative. According to various embodiments, the conductive portion 506 may be partially or completely surrounded by a dielectric material, or may be free of dielectric material. Figures 13A-13Q Various embodiments of the vertical legs 308 are described. However, first, a method for forming a vertical leg such as a vertical leg 308 will be discussed according to various embodiments. Figure 3 、 5Aand the vertical leg 308 of the vertical bolometer leg of step 5B.

[0107] Figures 6A-6F Shown are cross-sectional side views of a portion of a microbolometer array at various stages during the production of a microbolometer leg.

[0108] Now turn Figure 6A , a portion 601 of a microbolometer array is shown having contacts 310 and a bridge 302. As shown, the bridge 302 includes a sensor layer (e.g., a temperature-sensitive resistive material layer such as VO x ) 606 and one or more additional layers 604 (e.g., an absorber layer). As shown, contact 310 can be formed from a vertical conductive portion, such as a metal stud 608, and one or more layers (e.g., a metal contact layer 614 in contact with metal stud 608). Contact 310 can include additional layers (e.g., a dielectric layer 616 disposed on metal layer 614) and additional layers 612 (e.g., a passivation layer disposed under a portion of metal layer 614). As shown, layer 612 can be formed on a portion of the top surface 603 of sacrificial layer 600. In some cases, a basket contact or other contact can be utilized instead of metal stud 608.

[0109] Sacrificial layer 600 may be formed of, for example, polyimide. Layers 612 and 616 may be formed of, for example, silicon dioxide or silicon nitride. Metal layer 614 may be formed of titanium, tungsten, copper, aluminum, and / or other known metals.

[0110] The metal stud 608 can be conductively coupled to a conductive contact, such as a contact 610 of a substrate, such as a readout integrated circuit (ROIC) substrate, such as a complementary metal oxide semiconductor (CMOS) ROIC. Figure 6A In an embodiment, the contacts 610 are disposed on a cover glass layer 602 (e.g., a CMOS cover glass layer) of the ROIC. Before forming the vertical legs between the bridge 302 and the contacts 310, the bridge 302 can be disposed on a sacrificial layer 600 that supports the bridge 302 and fills the gap between the bridge of the microbolometer array and the ROIC, extending continuously between the bridge of the microbolometer array and the contacts.

[0111] According to one embodiment, the process for forming the vertical legs between the bridge 302 and the contact 310 may include depositing and patterning an additional sacrificial layer 620 on the sacrificial layer 600, such as Figure 6B. Patterning the additional sacrificial layer 620 may include forming an opening 622 in the additional sacrificial layer (e.g., at least partially between the bridge 302 and the contact 310) so that the remaining portion of the additional sacrificial layer 620 has vertical sidewalls 625. The opening 622 may extend into the sacrificial layer 600, or may extend only to the top surface 603 of the sacrificial layer 600 (as an example).

[0112] After the deposition and patterning of the additional sacrificial layer 620, a dielectric layer 624 may be deposited and patterned so that portions of the dielectric layer 624 remain on the sidewalls 625 of the additional sacrificial layer 620 in the opening 622, as shown in FIG. Figure 6C A metal layer may then be deposited over the contacts 310, portions of the sacrificial layer 600, the dielectric layer 624 on the sidewalls 625, portions of the additional sacrificial layer 620, and the bridge 302, as shown in FIG. Figure 6D If desired, openings can be formed in the dielectric layer of contacts 310 and bridge 302 to expose portions of metal layer 614 and sensor layer 606 so that metal layer 626 can be deposited in contact with metal layer 614 and sensor layer 606. Metal layer 626 can be deposited in a blank deposition process.

[0113] like Figure 6E As shown, an additional dielectric layer 628 can be deposited over the metal layer 626, and then the metal layer 626 and the additional dielectric layer 628 can be etched (e.g., in a masked spacer etch process) to remove portions of the metal layer 626 and the additional dielectric layer 628 from the sacrificial layer 600 and the additional sacrificial layer 620. In this manner, a dielectric-metal-dielectric stack can be formed vertically on the sidewalls 625 of the opening 622. Portions of the dielectric-metal-dielectric stack that are continuously coupled to the portions on the sidewalls 625 can also remain on the contact 310 and the bridge 302, thereby forming the bridge contact 306 and the leg metal in contact with the metal layer 614 of the contact 310.

[0114] Dielectric layers 624 and 628 can be formed of, for example, silicon dioxide or silicon nitride. Metal layer 626 can be a single metal layer forming a homogeneous film of a single material, or it can include multiple materials (e.g., multiple layers of the same or different materials formed in multiple deposition operations). For example, metal layer 626 can be formed of titanium, tungsten, copper, aluminum, and / or other known metals.

[0115] like Figure 6F As shown, the sacrificial layers 600 and 620 can then be removed to release the bridge 302 and vertical legs 308 still suspended above the ROIC with a space 650 between the vertical legs and the ROIC. Figure 6FThe vertical legs 308 appear to be floating, but this is only because of the particular cross-section of the device shown. Figure 6F The vertical legs 308 along Figure 6F The XY plane is extended, for example, as Figure 3 As shown, the metal layer 626 forms a continuous conductive path between the bridge contact 306 and the contact 310 . Figure 6F The vertical leg 308 can include at least a portion that extends non-perpendicularly to the plane defined by the surface 699 of the base plate 602. For example, the vertical leg 308 can extend along a path that is parallel to the surface 699. In another embodiment, the vertical leg 308 can extend along a path that includes a portion that is parallel to the surface 699 and an additional portion that bends downwardly toward the surface 699 at a non-perpendicular angle.

[0116] Figures 6A-6F The process shown is illustrative only. According to different embodiments, the vertical legs of the microbolometer array can be formed using other processes. For example, in one embodiment, a process such as Figures 7A-7F The process shown in FIG. 1 is to form a vertical leg that is arranged below the plane forming the bridge 302 (e.g., with Figure 6F 304 and 305. In contrast to the vertical leg of the bridge 302, the vertical leg is arranged substantially in a common plane with the bridge 302).

[0117] Now turn Figure 7A , shows a portion 701 of a microbolometer array having contacts 310 and a bridge 302. As shown, the bridge 302 includes a sensor layer (e.g., a temperature sensitive resistive material layer such as VO x ) 709 and one or more additional layers 707 (e.g., an absorber layer). As shown, contact 310 can be formed from a vertical conductive portion (e.g., a metal stud 708) and one or more layers (e.g., a metal contact layer 714 in contact with the metal stud 708). Contact 310 can include additional layers (e.g., a dielectric layer 716 disposed above the metal layer 714) and additional layers 712 (e.g., a passivation layer disposed below portions of the metal layer 714). As shown, passivation layer 712 can be formed on a portion of the top surface 703 of sacrificial layer 700.

[0118] Sacrificial layer 700 may be formed of, for example, polyimide. Layers 712 and 716 may be formed of, for example, silicon dioxide or silicon nitride. Metal layer 714 may be formed of titanium, tungsten, copper, aluminum, and / or other known metals.

[0119] The metal stud 708 (or in some cases, a basket contact) can be conductively coupled to a conductive contact, such as a contact 750 of a readout integrated circuit (ROIC), such as a complementary metal oxide semiconductor (CMOS) ROIC. Figure 7A In an embodiment, the contacts 750 are disposed in a glass cover layer 702 (e.g., a CMOS glass cover layer) of the ROIC. Before forming the vertical legs between the bridge 302 and the contacts 310, the bridge 302 can be disposed on a sacrificial layer 700 that supports the bridge 302 and fills the gap between the bridge of the microbolometer array and the ROIC, extending continuously between the bridge of the microbolometer array and the contacts.

[0120] According to one embodiment, the process for forming the vertical legs between the bridge 302 and the contact 310 may include forming an opening 704 in the sacrificial layer 700 supporting the bridge 302 (e.g., by etching through the surface 703), as shown. Figure 7B As shown. Opening 704 can be formed in a portion of sacrificial layer 700 that is at least partially disposed between bridge 302 and contact 310, such that opening 704 has vertical sidewalls 705 at different locations between bridge 302 and contact 310. As shown, sidewalls 705 can be substantially below a plane defined by bridge 302 (e.g., Figure 7B XY plane).

[0121] like Figure 7C As shown, dielectric layer 706 may be deposited and patterned so that portions of dielectric layer 706 remain on sidewalls 705 of sacrificial layer 700 in opening 704. Figure 7D As shown, openings, such as opening 713 in layer 707 of bridge 302 and dielectric layer 716, may also be formed to expose portions of sensor layer 709 and metal layer 714, respectively.

[0122] Then, if Figure 7E As shown, a metal layer (e.g., leg metal layer 710) is deposited over the contacts 310, portions of the sacrificial layer 700, the dielectric layer 706 on the sidewalls 705, and the bridge 302. The metal layer 710 can be deposited during a blank deposition process. As shown, portions of the metal layer 710 can be formed within the openings 713 (see FIG. Figure 7D ), and contacts the sensor layer 709 and the metal layer 714.

[0123] Additional dielectric layer 711 ( Figure 7F) can be deposited over the metal layer 710, and the metal layer 710 and the additional dielectric layer 711 can be etched (e.g., in a masked spacer etch process) to remove portions of the metal layer 710 and the additional dielectric layer 711 from the sacrificial layer 700. In this manner, a dielectric-metal-dielectric stack can be formed vertically on the sidewalls 705 of the opening 704, and portions of the dielectric-metal-dielectric stack continuously coupled to the portions on the sidewalls 705 can also remain on the contact 310 and the bridge 302, thereby forming the bridge contact 306 and the leg metal contact to the metal layer 714 of the contact 310.

[0124] Dielectric layers 706 and 711 can be formed of, for example, silicon dioxide or silicon nitride. Metal layer 710 can be a single metal layer, forming a homogeneous film of a single material, or it can include multiple materials (e.g., multiple layers of the same or different materials formed in multiple deposition operations). For example, metal layer 710 can be formed of titanium, tungsten, copper, aluminum, and / or other known metals.

[0125] like Figure 7F As shown, the sacrificial layer 700 can then be removed to release the bridge 302 and vertical leg 308 formed by the metal layer 710 and the dielectric layers 706 and 711 that partially surround the metal layer 710. As shown, the vertical leg 308 is still suspended above the ROIC with a space 720 between the vertical leg and the ROIC. In this way, the vertical leg 308 can be perpendicular to the ROIC. Figure 7F The XY plane is formed and along the path (for example, Figure 3 As shown), the path is arranged between the bridge 302 and the contact 310 Figure 7F 308 so that the metal layer 710 forms a continuous conductive path between the bridge contact 306 and the contact 310 through the leg 308 .

[0126] Figure 7F The vertical leg 308 may include at least a portion that extends non-perpendicularly to the plane defined by the surface 799 of the base plate 702. For example, the vertical leg 308 may continue along a path that is parallel to the surface 799. In another embodiment, the vertical leg 308 may continue along a path that includes a portion that is parallel to the surface 799 and an additional portion that bends downwardly toward the surface 799 at a non-perpendicular angle.

[0127] exist Figure 7FIn one embodiment, the legs coupling the bridge 302 to the contacts 310 may include a vertical portion 308 and a horizontal portion 718 extending between the bridge 302 and a first end of the vertical leg 308 and between a second, opposite end of the vertical leg 308 and the contacts 310. In various embodiments, the legs 308 may include any suitable combination of vertical and horizontal portions to provide adequate performance for the microbolometer while avoiding reducing the fill factor of the microbolometer array due to the area occupied by the legs.

[0128] Figures 8A-8C are cross-sectional side views of a portion of a microbolometer array at various stages in the vertical leg formation process, illustrating an alternative process for vertical leg formation.

[0129] Now turn Figure 8A , a portion 801 of a microbolometer array is shown having a contact 310 and a bridge 302. As shown, the bridge 302 includes a sensor layer (e.g., a temperature-sensitive resistive material layer such as VOx) 806 and one or more additional layers 807 (e.g., an absorber layer). As shown, the contact 310 can be formed from a vertical conductive portion such as a metal stud 803 and one or more layers (e.g., a metal contact layer 814 in contact with the metal stud 803). The contact 310 can include additional layers (e.g., a dielectric layer 816 disposed above the metal layer 814) and an additional layer 812 (e.g., a passivation layer disposed under a portion of the metal layer 814 and covering the top surface of the sacrificial layer 800). The passivation layer 812 can extend between the bridge 302 and the contact 310 on the top surface of the sacrificial layer 800.

[0130] Sacrificial layer 800 may be formed of, for example, polyimide. Layers 812 and 816 may be formed of, for example, silicon dioxide or silicon nitride. Metal layer 814 may be formed of titanium, tungsten, copper, aluminum, and / or other known metals.

[0131] The metal stud 803 (or in some cases, the basket contact) can be electrically conductively coupled to a conductive contact, such as contact 809 of a readout integrated circuit (ROIC) (such as a complementary metal oxide semiconductor (CMOS) ROIC). Figure 8A In an embodiment, the contacts 809 are disposed on a glass cover layer 802 (e.g., a CMOS glass cover layer) of the ROIC. Before forming the vertical legs between the bridge 302 and the contacts 310, the bridge 302 can be disposed on a sacrificial layer 800 that supports the bridge 302 and fills the gap between the microbolometer array and the bridge of the ROIC, extending continuously between the bridge of the microbolometer array and the contacts.

[0132] According to one embodiment, the process for forming the vertical leg between the bridge 302 and the contact 310 may include forming an opening 804 in a sacrificial layer 800 supporting the bridge 302 and in a passivation layer 812 disposed on the sacrificial layer, as shown in FIG. Figure 8A As shown, opening 804 can be formed in a portion of sacrificial layer 800 and passivation layer 812 that is at least partially disposed between bridge 302 and contact 310, such that opening 804 has vertical sidewalls 805 at different locations between bridge 302 and contact 310. As shown, sidewalls 805 can be formed by a portion of sacrificial layer 800 and passivation layer 812.

[0133] Then, before depositing dielectric layer 810 (over metal layer 808 ), a metal layer (e.g., leg metal layer 808 ) may be deposited (e.g., over contacts 310 , on portions of the top surface of passivation layer 812 , on sidewalls 805 in contact with sacrificial layer 800 and passivation layer 812 , on portions of sacrificial layer 800 in opening 804 , and on bridge 302 ), and metal layer 808 , dielectric layer 810 , and passivation layer 812 may be patterned (e.g., in a masked spacer etch process) so that metal layer 808 remains on some sidewalls of opening 804 , e.g., the sidewalls of passivation layer 812 . Figure 8B In this way, metal legs can be formed vertically on some sidewalls of the opening 804 , and a horizontal portion 818 of the metal layer 808 between the passivation layer 812 and the dielectric layer 810 can also remain on the sacrificial layer 800 .

[0134] For example, dielectric layer 810 can be formed of silicon dioxide or silicon nitride. Metal layer 808 can be a single metal layer forming a uniform thin film of a single material, or it can include multiple materials (e.g., multiple layers of the same or different materials formed in multiple deposition operations). For example, metal layer 808 can be formed of titanium, tungsten, copper, aluminum, and / or other known metals.

[0135] like Figure 8C As shown, the sacrificial layer 800 can then be removed to release the bridge 302 and the vertical leg 308 having the horizontal portion 818. As shown, the vertical leg 308 including the horizontal portion 818 is still suspended above the ROIC with a space 820 between the vertical leg and the ROIC. Figure 8C The vertical legs 308 including the horizontal portion 818 may form a continuous conductive path between the bridge contact 306 and the contact point 310 through the legs 308 .

[0136] Figure 8CThe vertical leg 308 may include at least a portion that extends non-perpendicularly to a plane defined by the surface 899 of the base plate 802. For example, the vertical leg 308 may extend along a path that is parallel to the surface 899. In another embodiment, the vertical leg 308 may extend along a path that includes a portion that is parallel to the surface 899 and another portion that bends downwardly toward the surface 899 at a non-perpendicular angle.

[0137] It is understandable that the above Figures 6A-8C The related processes may be modified, rearranged and / or omitted to form vertical bolometer legs having various shapes, sizes, orientations and arrangements to meet the needs of various purposes. Figure 9 、 10 , 11, 12, 13A-13Q, 14 and 15 show various arrangements of vertical legs and associated contacts or bridges that can be formed for a microbolometer array. In particular, Figure 9 and Figure 10 Portions of a microbolometer array are shown (before release by removal of a sacrificial layer) with vertical legs of the array formed below the plane of the bridge near the contacts of the microbolometers and the bridge, respectively, according to one embodiment. Figure 11 and 12 Portions of a microbolometer array according to another embodiment are shown having vertical legs formed below the plane of the bridge near contacts and bridges of the microbolometers, respectively. Figures 13A-13Q Various arrangements of metal and insulation for the vertical legs of the microbolometer are shown. Figure 14 and 15 Portions of a microbolometer array are shown having vertical legs formed on or above the face of a bridge in the vicinity of contacts and bridges of the microbolometers, respectively, according to another embodiment.

[0138] like Figure 9 As shown, at a particular stage of production, a portion of metal layer 714 may be formed on sacrificial layer 700, and a portion of dielectric layer 706 may extend over the portion of metal layer 714 formed on the sacrificial layer, over a vertical portion of metal layer 714 formed on stud 708, and over a horizontal portion of metal layer 714 formed on top of stud 708, such that the portion of dielectric layer 706 disposed over the top surface of sacrificial layer 700 is symmetrical on multiple sides of stud 708. Sacrificial layer 700 may then be removed.

[0139] According to one embodiment, the contact 310 is generated Figure 9 The process of structure can also form Figure 10 The bridge shown. Figure 10 As shown, bridge 302 may include bridge dielectric layers 1000 and 1002 disposed on opposite sides of sensor layer 606. Dielectric layer 706 may extend vertically from vertical leg structures 308 and cover a portion of bridge dielectric 1002. Metal layer 710 may cover the portion of dielectric layer 706 that extends vertically from vertical leg structures 308 and covers bridge dielectric 1002. The metal layer may extend through bridge dielectric 1002 and leg dielectric 706 to contact sensor layer 606.

[0140] In another embodiment, Figure 11 As shown, the metal layer 710 can be asymmetrical around the top of the stud 708 so that the metal layer 710 remains in contact with the metal layer 714 forming the contact 310 on one side of the vertical leg 308 on the stud 708, thereby increasing the contact area between the layers 710 and 714. Figure 11 After the structure is shown, the sacrificial layer 700 may be removed.

[0141] According to one embodiment, the contact 310 is caused Figure 11 The process of structure can also form Figure 12 The bridge shown. Figure 12 As shown, a portion of the metal layer 710 may be formed directly on a portion of the bridge dielectric 1002 such that the metal layer 710 passes through the portion of the bridge dielectric 1002 and contacts the sensor layer 606 through the bridge dielectric 1002 .

[0142] Figures 13A-13Q Each shows a cross-sectional view of an exemplary embodiment of a vertical bolometer leg, such as the vertical leg 308 described herein. Figure 13A As shown, the vertical bolometer leg may include a substantially vertical conductive (e.g., metal) layer 1300 disposed between first and second substantially vertical dielectric layers 1302 and 1304, the dielectric layers having a common height H with the vertical conductive layer 1300. Figure 13A In the configuration of , the vertical legs can have a width that is substantially the same along the height of the vertical legs and is substantially equal to the sum of the widths of layers 1300 , 1302 , and 1304 .

[0143] In general, the vertical bolometer legs may have: a first dimension (e.g., height H) extending in a direction perpendicular to the plane defined by the associated bolometer bridge and / or substrate; a second dimension (e.g., width W) extending in a direction parallel to the plane of the bridge and / or substrate; and a third dimension extending along and defining a signal path, wherein the path may include a portion extending in a direction parallel to the plane of the bridge and / or substrate, and the second dimension is substantially smaller than the first dimension.

[0144] like Figure 13B As shown, in one embodiment, dielectric layer 1302 may extend above the top of conductive layer 1300 and extend horizontally above the top of conductive layer 1300 and dielectric layer 1304. Figure 13C As shown, in one embodiment, conductive layer 1300 may have a height less than that of dielectric layer 1302 , and dielectric layer 1302 may extend below the bottom of conductive layer 1300 and dielectric layer 1304 .

[0145] like Figure 13D As shown, in one embodiment, dielectric layer 1302 may extend above the top of conductive layer 1300 and extend horizontally on top of conductive layer 1300 and dielectric layer 1304, and conductive layer 1300 may have a height shorter than the height of dielectric layer 1302, and dielectric layer 1304 may extend below the bottom of conductive layer 1300 to dielectric layer 1302. Figure 13E As shown, in one embodiment, conductive layer 1300 can have a height shorter than the height of dielectric layer 1302, dielectric layer 1304 can extend below the bottom of conductive layer 1300 to dielectric layer 1302, and horizontal dielectric layer 1306 can cover the tops of layers 1300, 1302 and 1304.

[0146] like Figure 13F As shown, in one embodiment, the conductive layer 1300 and the dielectric layers 1302 and 1304 may have a common height, and a horizontal dielectric layer 1306 may cover the tops of the layers 1300, 1302, and 1304. Figure 13G As shown, in one embodiment, the conductive layer 1300 may have a vertical portion and a horizontal portion, so that the conductive layer has an "L" shape in cross section. Figure 13G In the configuration, dielectric layer 1304 extends vertically along the vertical portion of conductive layer 1300 and extends horizontally under the vertical and horizontal portions of conductive layer 1300, and dielectric layer 1302 extends vertically along the vertical portion of conductive layer 1300, extends horizontally on top of the horizontal portion of conductive layer 1300, and vertically through the horizontal portion of conductive layer 1300 to the bottom of the vertical leg.

[0147] like Figure 13H As shown, in one embodiment, the conductive layer 1300 may be free of any surrounding dielectric material. Figure 13I As shown, in one embodiment, the conductive layer 1300 may have one side covered by the dielectric layer 1304 and an opposite side free of dielectric material. Figure 13JAs shown, in one embodiment, the height of the conductive layer 1300 having one side covered by the dielectric layer 1302 and the other side free of dielectric material can be shorter than the height of the vertical legs, and the dielectric layer 1302 can extend below the bottom of the conductive layer 1300. Figure 13K As shown, in one embodiment, conductive layer 1300 having one side covered by dielectric layer 1302 and an opposite side free of dielectric material may have a vertical portion and a horizontal portion extending over the top of dielectric layer 1302 .

[0148] like Figure 13L As shown, in one embodiment, the conductive layer 1300 having one side covered by the dielectric layer 1304 and an opposite side free of dielectric material may have a first vertical portion, a horizontal portion extending over the top of the dielectric layer 1304, and a second vertical portion offset from the first vertical portion. Figure 13L In the configuration of , dielectric layer 1304 may have a vertical portion extending along a first vertical portion of conductive layer 1300 and a horizontal portion extending below the first vertical portion of conductive layer 1300 to a second vertical portion of conductive layer 1300 .

[0149] like Figure 13M As shown, the conductive layer 1300 may include a vertical portion and a horizontal portion 1308 that extends horizontally from the bottom of the vertical portion of the conductive layer 1300 so that the conductive layer 1300 and the horizontal portion 1308 form an "L" shape. Figure 13M In the embodiment, the conductive layer 1300 is covered by a dielectric (insulating) layer 1302 on a first side, by a dielectric (insulating) layer 1304 on the other side, and by insulation (dielectric layer 1312) along the bottom surface of the horizontal portion 1308.

[0150] like Figure 13N As shown, in one embodiment, the horizontal portion 1308 and the portion below the top surface of the vertical portion can be substantially surrounded by one or more dielectric layers (such as dielectric layers 1302, 1304 and 1312) so that there is no dielectric material on the top of the vertical portion of the conductive layer 1300.

[0151] like Figure 13O As shown, in one embodiment, the conductive portion 1300 may have a vertical portion, a first horizontal portion extending from the top of the vertical portion in a first direction, a second horizontal portion extending from the bottom of the vertical portion in an opposite second direction, and an additional portion filling the space under the horizontal dielectric layer 1304 formed under the first horizontal portion. Figure 13OIn the configuration, the tops of the first horizontal portion, the vertical portion, and the second horizontal portion of the conductive layer 1300 are covered on one side by the dielectric layer 1302.

[0152] like Figure 13P As shown, in one embodiment, the conductive layer 1300 may have a vertical portion, a first horizontal portion extending from the top of the vertical portion in a first direction, and a second horizontal portion extending from the bottom of the vertical portion in an opposite second direction. Figure 13P In the configuration of FIG, the top of the first horizontal portion, the vertical portion, and the second horizontal portion of the conductive layer 1300 are covered on one side by the dielectric layer 1302, and the dielectric layer 1304 extends below the first horizontal portion of the conductive layer 1300 and fills the space. Figure 13Q As shown, a conductive layer having a vertical portion, a first horizontal portion extending from a top of the vertical portion in a first direction, and a second horizontal portion extending from a bottom of the vertical portion in an opposing second direction may be substantially surrounded by insulating material 1312 .

[0153] like Figure 14 As shown, at a particular stage of production of a vertical bolometer leg formed above and perpendicular to a surface 603 of a sacrificial layer such as sacrificial layer 600 (e.g., a sacrificial layer on which a bridge structure of one or more microbolometers is formed), a portion of metal layer 614 can be formed on sacrificial layer 600, while a portion of dielectric layer 624 can extend over the portion of metal layer 614 formed on the sacrificial layer, over the vertical portion of metal layer 614 over stud 608, and over the horizontal portion of metal layer 614 extending over the top of stud 608. Dielectric layer 624, leg metal layer 626, and dielectric layer 628 can form a horizontal portion 1400 that extends horizontally from contact 310 and turns vertically to form vertical leg portion 308. Sacrificial layer 600 can then be removed.

[0154] According to one embodiment, the contact 310 is formed Figure 14 The process of forming a structure can also be Figure 15 The bridge shown. Figure 15 As shown, bridge 302 may include bridge dielectric layers 1500 and 1502 disposed on opposite sides of sensor layer 606. Dielectric layer 624, metal layer 626, and dielectric layer 628 may form a stack that includes vertical leg portion 308 and portion 1504 extending horizontally from vertical leg portion 308 to bridge 302. As shown, metal layer 626 may cover a portion of dielectric layer 624 extending horizontally from vertical leg structure 308 and a portion of bridge dielectric 1502, and may contact sensor layer 606 through bridge dielectric 1502 and leg dielectric 624.

[0155] Figure 16 A top view of a portion of the vertical leg 308 in the curved region 312 is shown. Figure 17 and 18 Shown along Figure 16 A cross-sectional side view of an exemplary embodiment of the curved region 312 taken along line xx is shown. Figure 17 As shown, according to one embodiment, the bending region 312 may include a pad 1700 formed at the bottom of the vertical conductive layer 1702, which is interposed between the vertical dielectric layers 1704 and 1706 of the vertical legs. The pad 1700 may be formed of metal, dielectric material, or a combination of metal and dielectric materials (as examples). Figure 18 As shown, according to one embodiment, bend region 312 may include a metal pad 1800 formed on top of vertical conductive layer 1702 and vertical dielectric layers 1704 and 1706 of vertical legs. Pad 1800 may be formed of metal, dielectric material, or a combination of metal and dielectric materials (as examples).

[0156] Figure 19 is a cross-sectional side view of a portion of a microbolometer array at a particular stage of production, illustrating how, in one embodiment, at least a portion of a vertical leg structure may be formed beneath a bridge 302 of the microbolometer. Figure 19 As shown, the bridge 302 may include a sensor layer 606 disposed between bridge dielectric layers 1908 and 1910. The bridge dielectric layer 1910 may be formed on a first sacrificial layer 1904 interposed between the bridge dielectric layer 1910 and vertical leg structures 1906 beneath the bridge dielectric layer 1910 and the cover glass 1902 of the ROIC for the microbolometer array. Figure 19 At the production stage shown, a second sacrificial layer 1900 may be disposed between the vertical leg structures 1906 and the cover glass 1902 .

[0157] exist Figure 19In the illustrated configuration, the sensor layer 606 of the bridge 302 includes a vertical portion that extends downward from the bridge 302 and turns horizontally to form a portion of the bridge contact 306. As shown, a conductive layer (e.g., conductive layer 1911) can couple the sensor material 606 in the bridge contact region 306 to a vertical leg structure 1906. The vertical leg structure 1906 can extend to a contact, such as a stud contact or a basket contact, coupling the vertical leg structure 1906 to a contact on the ROIC (e.g., a contact formed partially or completely within the cover glass layer 1902). The vertical leg structure 1906 can couple to a dedicated contact structure of the bridge 302 formed thereunder and / or can couple to a shared contact with an adjacent microbolometer.

[0158] Figure 20 is a flow chart of illustrative operations that may be used to form vertical microbolometer legs for coupling a microbolometer bridge to a ROIC contact structure, according to one embodiment.

[0159] At block 2000, an imaging device having a contact structure and a bolometer bridge structure (e.g., a microbolometer bridge structure) may be provided. The imaging device may include a partially fabricated focal plane array on which a sacrificial layer, such as a polyimide layer, is formed on a substrate, such as a readout integrated circuit, and the bridge structure is formed on the sacrificial layer. In some embodiments, an etch stop layer may be formed on the sacrificial layer. However, in other embodiments, the sacrificial layer may not contain any etch stop material. The contact structure may include electrical contacts on the readout integrated circuit and, if desired, conductive elements extending from the electrical contacts on the ROIC to part or all of the sacrificial layer. The conductive elements may include studs or basket contacts and, if desired, may include one or more additional structures, such as a passivation layer, a metal layer, and / or a dielectric layer formed on the conductive elements.

[0160] At block 2002, an additional sacrificial layer may be deposited and patterned over or on the sacrificial layer. In an embodiment, an etch stop layer is provided on the sacrificial layer, and the additional sacrificial layer may be deposited on the etch stop layer such that portions of the etch stop layer are formed between the sacrificial layer and the additional sacrificial layer. Patterning the additional sacrificial layer may include etching the additional sacrificial layer to form an opening in the additional sacrificial layer at least partially between the bridge structure and the contact structure.

[0161] At block 2004, a first leg dielectric material may be formed on at least the sidewalls of the opening in the patterned additional sacrificial layer. Forming the first leg dielectric material on the sidewalls of the opening may include depositing a first leg dielectric layer and performing a spacer etching on the first leg dielectric layer. The etching may also leave portions of the first leg dielectric layer on portions of the contact structure and / or bridge structure as desired.

[0162] At block 2006, one or more conductive layers (e.g., leg metal layers) can be deposited (e.g., using blanket metal deposition) and patterned on the first leg dielectric material on the sidewalls of the opening and over at least some of the contact structures and the bridge structure. The leg metal layers can be formed in contact with the metal layers of the contact structures and the sensor layer of the bridge structure.

[0163] A second leg dielectric layer may be deposited and patterned on the metal layer at block 2008. Patterning the second leg dielectric layer may include depositing the second leg dielectric layer over the leg metal layer before patterning the leg metal layer and performing in-situ dielectric and metal etching on the leg metal layer and the second leg dielectric layer.

[0164] At block 2010, the sacrificial layer and additional sacrificial layers may be removed to release the bridge structure and vertical leg structures formed by the first and second leg dielectric layers and the leg metal layers, such that the bridge and legs are suspended above the readout integrated circuit, and the contact structure is coupled to the bridge structure via the vertical leg structure. In an embodiment, an etch stop layer is provided over the sacrificial layer, and portions of the etch stop layer may also be removed.

[0165] Figure 21 is a flow chart of illustrative operations that may be used to form vertical microbolometer legs for coupling a microbolometer bridge to a ROIC contact structure, according to another embodiment.

[0166] At block 2100, an imaging device having a contact structure and a bolometer bridge structure (e.g., a microbolometer bridge structure) can be provided. The imaging device can include a partially fabricated focal plane array having a sacrificial layer (e.g., a polyimide layer) formed on a readout integrated circuit and the bridge structure formed on the sacrificial layer. The contact structure can include electrical contacts on the readout integrated circuit and, if desired, conductive elements extending from the electrical contacts on the ROIC to part or all of the sacrificial layer. The conductive elements can include studs or basket contacts, and, if desired, one or more additional structures, such as a passivation layer, a metal layer, and / or a dielectric layer, can also be formed on the conductive elements.

[0167] At block 2102 , a sacrificial layer may be etched to form an opening in the sacrificial layer at least partially between the bridge structure and the contact structure.

[0168] At block 2104, a first leg dielectric material may be formed on at least the sidewalls of the opening in the sacrificial layer. Forming the first leg dielectric material on the sidewalls of the opening may include depositing a first leg dielectric layer and performing a spacer etch of the first leg dielectric layer. The etch may also be performed to leave desired portions of the first leg dielectric layer on portions of the contact structure and / or bridge structure.

[0169] At block 2106, openings may be formed in the dielectric layers of the contact structure and the bridge structure. Forming the openings in the dielectric layers of the contact structure and the bridge structure may expose portions of the metal layer of the contact structure and / or the sensor layer of the bridge structure.

[0170] At block 2108, one or more conductive layers (e.g., leg metal layers) may be deposited (e.g., using blanket metal deposition) and patterned on the first leg dielectric material on the sidewalls of the opening and over at least some of the contact structures and the bridge structure. The leg metal layers may be formed in contact with exposed portions of the metal layers of the contact structures and the sensor layer of the bridge structure.

[0171] A second leg dielectric layer may be deposited and patterned on the metal layer at block 2110. Patterning the second leg dielectric layer may include depositing the second leg dielectric layer on the leg metal layer before patterning the leg metal layer and performing in-situ dielectric and metal etching on the leg metal layer and the second leg dielectric layer.

[0172] At block 2112 , the sacrificial layer may be removed to release the bridge structure and the vertical leg structure formed by the first and second leg dielectric layers and the leg metal layer so that the bridge and legs are suspended above the readout integrated circuit and the contact structure is coupled to the bridge structure through the vertical leg structure.

[0173] Figure 22 is a flow chart of illustrative operations that may be used to form vertical microbolometer legs for coupling a microbolometer bridge to a ROIC contact structure, according to another embodiment.

[0174] At block 2200, an imaging device having a contact structure and a bolometer bridge structure (e.g., a microbolometer bridge structure) can be provided. The imaging device can include a partially fabricated focal plane array having a sacrificial layer (e.g., a polyimide layer) formed on a readout integrated circuit, a passivation layer formed on at least a portion of the sacrificial layer, and a bridge structure formed on the sacrificial layer. The contact structure can include electrical contacts on the readout integrated circuit and, if desired, conductive elements extending from the electrical contacts on the ROIC to part or all of the sacrificial layer. The conductive elements can include studs or basket contacts and, if desired, one or more additional structures, such as portions of a passivation layer, a metal layer, and / or a dielectric layer, formed above the conductive elements.

[0175] At block 2202 , the sacrificial layer and the passivation layer may be etched to form an opening in the sacrificial layer and the passivation layer at least partially between the bridge structure and the contact structure.

[0176] At block 2204 , one or more conductive layers, such as a leg metal layer, may be deposited (eg, using blank metal deposition) and patterned on sidewalls of the opening and over portions of the passivation layer on at least some of the contact structures, bridge structures, and sacrificial layer.

[0177] A leg dielectric layer may be deposited and patterned on the metal layer at block 2206. Patterning the leg dielectric layer may include depositing the leg dielectric layer on the leg metal layer prior to patterning the leg metal layer and performing in-situ dielectric and metal etching on the leg metal layer and the second leg dielectric layer.

[0178] At block 2208, the sacrificial layer may be removed to release the bridge structure and the vertical leg structure formed by portions of the passivation layer, the leg dielectric layer, and the leg metal layer so that the bridge and the legs are suspended above the readout integrated circuit and the contact structure is coupled to the bridge structure through the vertical leg structure.

[0179] The process for forming the vertical microbolometer legs described above is merely illustrative. According to various embodiments, the vertical legs of the microbolometer array may be formed using other processes. For example, in one embodiment, a process such as Figures 23A-23F The process shown uses an etch stop layer to form the vertical legs.

[0180] Figures 23A-23F Shown are cross-sectional side views of a portion of a microbolometer array at various stages during the production of a microbolometer leg for the microbolometer array.

[0181] Now turn Figure 23A, a portion 2398 of a microbolometer array is shown having a contact 310 and a bridge 302. As shown, the bridge 302 includes a sensor layer (e.g., a temperature-sensitive resistive material layer, such as VOx) 2306 and one or more additional layers 2304, such as an absorber layer. As shown, the contact 310 can be formed from a vertical conductive portion, such as a metal stud 2308, and one or more layers, such as a metal contact layer 2314, that contacts the metal stud 2308. The contact 310 can include additional layers, such as a passivation layer 2316 disposed beneath portions of the metal layer 2314. As shown, additional layers, such as an etch stop layer 2303 (e.g., a layer of dielectric material), can be formed on the sacrificial layer 2300 and can extend to form a portion of the bridge 302 and / or the contact 310.

[0182] Sacrificial layer 2300 may be formed of, for example, polyimide. Layers 2303 and 2316 may be formed of, for example, silicon dioxide or silicon nitride. Metal layer 2314 may be formed of titanium, tungsten, copper, aluminum, and / or other known metals.

[0183] The metal studs 2308 can be conductively coupled to conductive contacts, such as contacts 2310 of a substrate, such as a readout integrated circuit (ROIC) substrate, such as a complementary metal oxide semiconductor (CMOS) ROIC. Figure 23A In an embodiment, the contacts 2310 are disposed on a cover glass layer 2302 (e.g., a CMOS cover glass layer) of the ROIC. Before forming the vertical legs between the bridge 302 and the contacts 310, the bridge 302 can be disposed on the sacrificial layer 2300 so that the sacrificial layer fills the gap between the bridge of the microbolometer array and the ROIC and extends continuously between the bridge of the microbolometer array and the contacts.

[0184] According to one embodiment, the process for forming the vertical leg between the bridge 302 and the contact 310 may include depositing and patterning an additional sacrificial layer 2320 on the etch stop layer 2303, such as Figure 23B . The patterning of the additional sacrificial layer 2320 may include forming an opening 2322 in the additional sacrificial layer (e.g., at least partially between the bridge 302 and the contact 310) so that the remaining portion of the additional sacrificial layer 2320 has vertical sidewalls 2325. The opening 2322 may extend to the top surface 2301 of the etch stop layer 2303.

[0185] After the deposition and patterning of the additional sacrificial layer 2320, a dielectric layer 2324 may be deposited and patterned so that portions of the dielectric layer 2324 remain on the sidewalls 2325 of the additional sacrificial layer 2320 in the opening 2322, as shown. Figure 23C Then, as Figure 23DAs shown, a metal layer, such as leg metal layer 2326, can be deposited over contacts 310, portions of etch stop layer 2303, dielectric layer 2324 on sidewalls 2325, portions of additional sacrificial layer 2320, and bridge 302. If desired, openings can be formed in portions of etch stop layer 2303, positioned over contacts 310 and bridge 302, to expose portions of metal layer 2314 and sensor layer 2306 so that metal layer 2326 can be deposited in contact with metal layer 2314 and sensor layer 2306. Metal layer 2326 can be deposited in a blank deposition process.

[0186] like Figure 23E As shown, an additional dielectric layer 2328 can be deposited on the metal layer 2326, and then the metal layer 2326 and the additional dielectric layer 2328 can be etched (e.g., in a masked spacer etch process) to remove portions of the metal layer 2326 and the additional dielectric layer 2328 from the etch stop layer 2303 and the additional sacrificial layer 2320. In this manner, a dielectric-metal-dielectric stack can be formed vertically on the sidewalls 2325 of the opening 2322. Portions of the dielectric-metal-dielectric stack that are continuously coupled to the portions on the sidewalls 2325 can also remain on the contact 310 and the bridge 302, thereby forming the bridge contact 306 and the leg metal in contact with the metal layer 2314 of the contact 310.

[0187] Dielectric layers 2324 and 2328 may be formed of silicon dioxide or silicon nitride, as examples. Metal layer 2326 may be a single metal layer forming a homogeneous film of a single material, or may include multiple materials (e.g., multiple layers of the same or different materials formed in multiple deposition operations). For example, metal layer 2326 may be formed of titanium, tungsten, copper, aluminum, and / or other known metals.

[0188] like Figure 23F As shown, portions of the sacrificial layers 2300 and 2320 and the etch stop layer 2303 may be removed to release the bridge 302 and vertical legs 308 suspended above the ROIC with a space 2350 between the vertical legs and the ROIC. Figure 23F The vertical leg 308 may include at least a portion that extends non-perpendicularly to the plane defined by the surface 2399 of the base plate 2302. For example, the vertical leg 308 may extend along a path parallel to the surface 2399. In another embodiment, the vertical leg 308 may extend along a path that includes a portion parallel to the surface 2399 and an additional portion that bends downwardly toward the surface 2399 at a non-perpendicular angle.

[0189] Figure 24A cross-sectional side view of a microbolometer bridge coupled with legs formed under the bridge is shown according to one embodiment. Figure 24 In the embodiment of the present invention, the bridge 302 includes a sensor layer 2400 formed generally between bridge dielectric layers 2402 and 2404. The sensor layer 240 (eg, a temperature sensitive resistive material such as VO x ) may include one or more horizontal portions extending in a plane parallel to the surface of the substrate on which the bridge 302 is formed, and may include a plurality of portions 2406 extending downward from the horizontal portions in the direction of the substrate (e.g., perpendicular to the surface of the substrate). Portions 2406 may extend to contact one or more legs, such as legs 2420 formed below the bridge 302 (e.g., at least partially disposed between the bridge 302 and the substrate above which the bridge is positioned).

[0190] like Figure 24 As shown, a leg 2420 formed of a conductive material has a horizontal portion 2408 in contact with the sensor layer 2306 and a vertical portion 2410 extending perpendicular to the horizontal portion 2408. However, this is merely illustrative. In various embodiments, the leg 2420 can include vertical and / or horizontal portions and / or can be partially or completely covered in an insulating material, such as in any of the embodiments described herein.

[0191] To form Figure 24 For a bridge of the type shown, illustrative operations may be performed in Figure 25 Shown in.

[0192] At block 2500, an imaging device having a contact structure formed on and / or in a sacrificial layer can be provided. The imaging device can include a partially fabricated focal plane array on which a sacrificial layer, such as a polyimide layer, is formed on a substrate, such as a readout integrated circuit substrate. The contact structure can include electrical contacts on the substrate and, if desired, conductive elements extending from the electrical contacts on the ROIC to part or all of the sacrificial layer. The conductive elements can include studs or basket contacts and, if desired, one or more additional structures formed above the conductive elements, such as a passivation layer, a metal layer, and / or a dielectric layer.

[0193] At block 2502 , an opening may be formed in a sacrificial layer.

[0194] At block 2504, a first leg dielectric material may be formed on at least the sidewalls of the opening in the sacrificial layer. Forming the first leg dielectric material on the sidewalls of the opening may include depositing a first leg dielectric layer and performing a spacer etch of the first leg dielectric layer.

[0195] At block 2506, one or more conductive layers (e.g., leg metal layers) can be deposited (e.g., using blanket metal deposition) and patterned over the first leg dielectric material on the sidewalls of the opening and over at least some of the contact structures. The leg metal layers can be formed in contact with the metal layers of the contact structures.

[0196] A second leg dielectric layer may be deposited and patterned on the leg metal layer at block 2508. Patterning the second leg dielectric layer may include depositing the second leg dielectric layer over the leg metal layer before patterning the leg metal layer, and performing in-situ dielectric and metal etching on the leg metal layer and the second leg dielectric layer.

[0197] At block 2510 , an additional sacrificial layer may be deposited over the sacrificial layer.

[0198] At block 2512 , one or more bolometer bridge contacts may be formed in the second sacrificial layer.

[0199] At block 2514 , a first bridge dielectric layer may be deposited.

[0200] At block 2516 , one or more contacts may be formed in the underlying second leg dielectric layer over the first bridge dielectric layer and the leg metal layer for connection to the leg metal layer.

[0201] At block 2518 , a bolometer resistive sensing material (eg, a temperature sensitive resistive material such as VOx) may be deposited and patterned to form a sensor layer of the bolometer bridge.

[0202] At block 2520 , a second bridge dielectric material may be deposited and patterned to define a bridge region for each microbolometer formed on at least a portion of the underlying leg material.

[0203] At block 2522 , the sacrificial layer and additional sacrificial layers may be removed to release the bridge structure and vertical leg structures, whereby the bridge and legs formed beneath the bridge are suspended above the substrate and the contact structure is coupled to the bridge structure through the vertical leg structures.

[0204] In traditional bolometer fabrication methods, patterning is performed along the X and Y dimensions, while the material thickness is deposited as a sheet-like film in the Z dimension. The sheet-like film controls the thickness of the device in the Z dimension. Figure 26 A top view of the bolometer is shown. Figure 27 Shown along Figure 2626. A cross section of a leg of line 2605. In particular, the cross section is a cut along line 2605 in the x-direction (e.g., horizontal width direction) and viewed in the y-direction (e.g., length direction of the leg). The leg includes: an insulator material 2705; a conductive layer 2710 disposed on the insulator material 2705; and an insulator material 2715 disposed on the conductive layer 2710. The insulator material 2705, the conductive layer 2710, and the insulator material 2715 are disposed one above the other along the z-dimension. It should be noted that Figure 27 One embodiment is shown where the material deposition thickness (MDT) is similar for insulator material 2705, conductive layer 2710, and insulator material 2715. However, the MDT between these materials / layers need not be the same.

[0205] As pixel size decreases, the amount of area in the X and Y directions also decreases. To increase sensitivity, the thickness of the bolometer material is also reduced. This reduction in bolometer material thickness is associated with a corresponding reduction in the amount of structural support built into the bolometer. To increase the rigidity of this reduced-size bolometer, a vertical member can be added to the bolometer structure.

[0206] Figure 28 The figure shows, for example, the stiffness provided by vertical components. A flat piece of metal has a total mass M. If supported at both ends, it can support a certain weight, W1. If this piece of metal, with a total mass M, is formed into an I-beam or other similar structure with vertical sections, it can support a weight, W2, which is greater than W1.

[0207] With smaller pixels, the material thickness is reduced to support the desired performance. As the material becomes thinner, stiffness decreases, until the bolometer legs are unable to support the bolometer's mass without introducing vertical members to stiffen and support the pixel. In the design of the vertical legs, the material thickness can be controlled more than the Z dimension. Variations in the height of the vertical members in the legs can affect the thermal and electrical properties of the legs. This impact on thermal and electrical properties can have an impact on the performance of the bolometer.

[0208] Figure 29 A top view of a microbolometer array with vertical legs is shown, according to one embodiment. Figure 30A Shown along Figure 29A cross section of one leg of line 2905. In particular, the cross section is a cut along line 2905 in the x-direction (e.g., horizontal width direction) and viewed in the y-direction (e.g., in the leg length direction). The leg has a Z-shaped cross section (e.g., also considered an S-shaped cross section). The leg includes an insulator material 3005, a conductive layer 3010 disposed on the insulator material 3005, and an insulator material 3015 disposed on the conductive layer 3010. The insulator material 3005, the conductive layer 3010, and the insulator material 3015 are disposed one after another along the Z-shaped dimension. The z-shaped cross section provides a path from the bridge to the contact. The contact can be a contact of the substrate. Portions 2910 and 2915 of the thermal radiation meter show the transition region from the respective legs to the respective contacts. It should be noted that Figure 30A An embodiment is shown where the MDTs of the insulator material 3005, the conductive layer 3010, and the insulator material 3015 are approximately the same. However, the MDTs between these materials / layers do not have to be the same.

[0209] like Figure 30A As shown, the serpentine cross-section of the leg has: a first section (e.g., a left section or a lower section); a second section (e.g., a right section or an upper section) that is substantially parallel to the first section; and a third section (e.g., a middle section) connecting the first section and the second section. To connect the bridge to the contacts of the substrate, the leg can extend between the bridge and the contact in a first direction (e.g., an X direction) and / or a second direction (e.g., a Y direction) that are substantially parallel to the plane of the substrate. The serpentine cross-section (e.g., an S-shape or a Z-shape) is maintained along the X- and / or Y-directions. In this regard, the first section and the second section extend in the first direction and / or the second direction that are substantially parallel to the plane. The third section connects the first section and the second section in a third direction (e.g., a Z-direction) that is substantially perpendicular to the plane.

[0210] about Figure 30AIn the particular cross-section of the leg shown, the leg has a segment 3020 associated with the first section, a segment 3025 associated with the second section, and a segment 3030 associated with the third section. Segment 3030 is adjacent to segments 3020 and 3025. Each of segments 3020, 3025, and 3030 has a first dimension (e.g., width) extending in the X direction substantially parallel to a plane of the substrate surface, and a second dimension (e.g., height) extending in the Z direction substantially perpendicular to the plane. For segments 3020 and 3025, the first dimension is greater than the second dimension. For segment 3030, the first dimension is less than the second dimension. Each of segments 3020, 3025, and 3030 has a corresponding portion of insulator material 3005, a corresponding portion of conductive layer 3010, and a corresponding portion of insulator material 3015. Insulator material 3005 is formed on a first sidewall and a first side of conductive layer 3010. Insulator material 3015 is formed on the second sidewall of conductive layer 3010 and the second side of conductive layer 3010. The first sidewall is opposite the second sidewall. The first sidewall is substantially perpendicular to the first side. The first side is opposite the second side. In some aspects, two segments / sections / portions may be referred to as being substantially perpendicular if the angle between them is within ±10° of 90°. In some aspects, two segments / sections / portions may be referred to as being substantially parallel if the angle between them is within ±10° of 0°.

[0211] Various methods can be used to define the vertical portion of the legs. Each method is associated with complexity, variability, and materials (e.g., affecting performance). The deposited film can have ideal uniformity across the entire wafer and have small variations in different continuity (e.g., wafer to wafer). In this way, the deposited film can be used to control the vertical portion. In one aspect, the thermal radiation meter can include a deposited film of a conductive material (such as a metal) and a deposited film of a non-conductive material (such as an insulator). Dry etching associated with traditional CMOS processing can be used to selectively remove one type of film from another (e.g., metal can be removed where there is no insulator protection). For example, the insulator is a barrier to metal etching, and the metal is a barrier to insulator etching. After etching, the legs may have insulator and / or metal remaining on the legs, which will affect the performance of the thermal radiation meter.

[0212] In some aspects, the Z-height of the legs can be reduced (e.g., relative to Figure 30A ) while creating additional rigidity for the bolometer. Figure 30B According to one embodiment, a Figure 30A The smaller the leg height, the smaller the leg cross-section. Figure 30BThe leg of has a segment 3035 (e.g., associated with the first section), a segment 3040 (e.g., associated with the second section), and a segment 3045 (e.g., associated with the third section). In one aspect, segments 3035, 3040, and 3045 can be considered to correspond to Figure 30A Leg segments 3020, 3025, and 3030. In some cases, given that the Z dimension exceeds a required threshold to meet the minimum stiffness of the bolometer, depending on the specific implementation, it may be more meaningful to control the height of the entire wafer rather than the actual average of the Z dimension.

[0213] Although Figure 30A and 30B In the embodiment, the third section is substantially perpendicular to the first section and the second section, but in various embodiments, the third section is at an angle (e.g., nominally at an angle) relative to the first and second sections. In this regard, such a third section is similar to Figure 30A and 30B The third section shown in FIG is tilted in comparison. Figure 31 An example cross section of a leg 3100 having an inclined portion according to one or more embodiments is shown. The cross section of the leg 3100 has a first section, a second section substantially parallel to the first section, and a third section that is inclined and joins the first and second sections. Figure 31 In the particular cross-section of the leg 3100 shown, the leg 3100 has a segment 3105 associated with the first section, a segment 3110 associated with the second section, and a segment 3115 associated with the third section. The segment 3115 is at about 45 degrees relative to the horizontal axis (e.g., left-right direction) associated with the segments 3105 and 3110. In other embodiments of the leg structure, the intermediate section may be Figures 30A-30B (e.g., substantially perpendicular to its adjacent sections) and Figure 31 The angle shown in FIG is different (e.g., about 45° relative to its adjacent sections). By way of non-limiting example, the intermediate sections can be angled about 30° to 60° relative to the horizontal axis associated with segments 3105 and / or 3110.

[0214] Leg 3100 includes a dielectric layer 3120, a dielectric layer 3125 disposed on dielectric layer 3120, a leg metal layer 3130 disposed on dielectric layer 3125, and a dielectric layer 3135 disposed on leg metal layer 3130. In this regard, leg metal layer 3130 is surrounded on at least two opposing sides by dielectric layers 3135 and 3125. Leg 3100 includes a tail portion 3140 of dielectric layer 3120. A gap 3145 is defined between tail portion 3140 and one side of dielectric layer 3125, such that tail portion 3140 faces dielectric layer 3125. In one aspect, tail portion 3140 may be formed as a result of an etching operation performed to form leg 3100.

[0215] In one or more embodiments, the leg manufacturing process may include or may be based on directed self-assembly (DSA) (e.g., polymer-based), oxide patterning, and / or other. Each process has several variations. Different processes may be associated with different process complexities, exposure resolutions, overlays, etc. In some aspects, each process has variations in the device feature order. For example, the legs, contacts, and bridges may be processed in any order. Each device feature order is associated with its set of trade-offs (e.g., complexity, cost, etc.). In some aspects, various paths / options that facilitate vertical leg manufacturing can allow the legs to be processed separately from the bridge. In some cases, the leg material can be independent of (e.g., completely independent of) the bridge. In some cases, some of the leg material is on the bridge (e.g., in contact with the bridge). Higher independence between the legs and the bridge is generally associated with more complex processes.

[0216] As an example, Figure 32 A top view of a bolometer with a bridge 3320, vertical legs, and contacts 3315 and 3350 is shown, wherein the bolometer is fabricated using an oxide method according to one embodiment. In some cases, the oxide method may be associated with lower process complexity than the DSA method. The oxide method may facilitate model correlation / feedback. Figure 33 Shown along Figure 32 A cross-section of a leg of line 3205 is shown. The bolometer includes: a substrate 3305; a pad 3310; a contact 3315 (e.g., a basket contact, a stud contact); a bridge 3320; and leg portions 3325, 3330, 3335, 3340, and 3345; and a contact 3350. Portions 3325 and 3330 provide a path between contact 3315 and bridge 3320, with leg portion 3330 transitioning to bridge 3320. Portions 3335, 3340, and 3345 provide a path between contact 3350 and bridge 3320. Portion 3335 transitions to bridge 3320.

[0217] As another example, Figure 34 A top view of a bolometer with a bridge 3520, vertical legs, and contacts 3515 and 3560 is shown, wherein the bolometer is fabricated using a DSA method according to one embodiment. Figure 35 The legs according to one embodiment are shown along Figure 343405. The bolometer includes a substrate 3505, a pad 3510, a contact 3515 (e.g., a basket contact), a bridge 3520, leg portions 3525, 3530, 3535, 3540, 3545, 3550, and 3555, and a contact 3560. Portions 3525 and 3530 provide a path between contact 3515 and bridge 3520, and leg portion 3530 transitions to bridge 3320. Portions 3535, 3540, 3545, 3550, and 3555 provide a path between contact 3560 and bridge 3520. Portion 3535 transitions to bridge 3520. Figure 35 A magnified view of a portion of a leg is shown in FIG. The leg comprises a vertically stacked arrangement of SiO2, leg metal, and Si. A portion of the silicon dioxide is disposed on the metal leg. A portion of the SiO2 is located below the leg metal and Si. These materials are provided by way of non-limiting example.

[0218] Figures 36A to 36N A cross-sectional side view is shown in connection with an example process for forming a bolometer according to one embodiment. Figure 37 According to one embodiment, Figure 36N The cross-sectional side view corresponds to the top view.

[0219] exist Figure 36A In the embodiment, a readout circuit chip 3600 (e.g., an ROIC chip) is provided. The readout circuit chip 3600 includes a substrate 3601, a glass layer 3602, and a metal layer 3603. The cover glass layer 3602 is disposed on the substrate 3601. The metal layer 3603 extends through the cover glass layer 3602. A thermal radiation meter process is performed on the readout circuit chip 3600 to form a thermal radiation meter connected to the readout circuit chip 3600. Figure 36B to 3 6O, describes an embodiment of a thermal radiation meter process. Figure 36B In FIG, pads 3604 are arranged on the readout circuit wafer 3600. Pads 3604 may form part of one or more metal layers. Figure 36C , a release layer 3606 (e.g., also referred to as a sacrificial layer) is disposed on the cover glass layer 3602 and the pad 3604, and a protective layer 3608 is disposed on the release layer 3606. The release layer 3606 may be a polyimide coating. The protective layer 3608 may be deposited as a thin film over the release layer 3606.

[0220] exist Figure 36D, metal layer 3612 is disposed on protective layer 3608, and dielectric layer 3614 is disposed on metal layer 3612. Metal layer 3612 may be a titanium layer. In some cases, metal layer 3612 may form or may be referred to as an absorber layer. In these cases, the absorber layer may be formed of, for example, titanium. Metal layer 3612 may serve as an etch stop layer for subsequent etching operations (e.g., allowing etching of the oxide layer(s) down to metal layer 3612). Dielectric layer 3614 may be formed of Si3N4. Metal layer 3612 and dielectric layer 3614 may be deposited as thin films.

[0221] exist Figure 36E , the metal layer 3612 and the dielectric layer 3614 are etched. To facilitate the etching of the metal layer 3612 and the dielectric layer 3614, one or more patterning operations may be performed. Generally, prior to the etching operation, a photoresist is deposited and patterned to define the portion of material to be etched / removed, and each etching operation may be isotropic or anisotropic. Patterning may include depositing a photoresist layer and exposing the photoresist layer to determine multiple portions of the metal layer 3612 and the dielectric layer 3614 to be etched. Etching may be performed on the metal layer 3612 and the dielectric layer 3614, and then the photoresist layer may be removed. In one aspect, a first etching operation (e.g., reactive ion etching) may be performed to etch down through the dielectric layer 3612 to the metal layer 3614. A second etching operation (e.g., a different chemical composition than the first etching operation) may be performed to etch down through the metal layer 3614 to the protective layer 3608. Block 3616 may identify the portions of metal layer 3612 and dielectric layer 3614 that remain after etching. In some cases, block 3616 may represent a mask material used to facilitate patterning and etching to obtain metal layer 3612 and dielectric layer 3614, such as Figure 36E shown.

[0222] exist Figure 36F In the embodiment, a resistive layer 3622 (eg, VO x layer, TiO x The resistive layer 3622 is configured such that the resistive layer 3622 contacts the protective layer 3608, the metal layer 3612, and the dielectric layer 3614. The dielectric layer 3624 is disposed on the resistive layer 3622. The dielectric layer 3624 may be a cap layer for the resistive layer 3622. Figure 36G36, the resistive layer 3622 and the dielectric layer 3624 are etched. This etching may etch the resistive layer 3622 and the dielectric layer 3624 so that they define the thermistors of the bolometer to be formed. Block 3630 identifies the portion of the resistive layer 3622 and the dielectric layer 3624 that remains after etching. In some cases, block 3630 may represent a mask material used to facilitate patterning and etching to obtain the resistive layer 3622 and the dielectric layer 3624, such as Figure 36G As shown. Block 3630 can be considered as defining the sensing portion of the bridge and the non-sensing portion of the bridge. The sensing portion of the bridge has a resistive layer 3622, while the non-sensing portion of the bridge does not have a resistive layer 3622. Figure 36G , the sensing portion of the bridge is located directly beneath block 3630 and is associated with region 3660, while the non-sensing portion of the bridge is associated with regions 3662 and 3664 adjacent to region 3660. Regions 3662 and 3664 can form a region surrounding region 3660. In some embodiments, the non-sensing portion of the bridge can have perforations defined therein to reduce the thermal mass associated with the bridge. Figure 49 , describes one embodiment of a bridge having perforations defined in a non-sensing portion of the bridge.

[0223] exist Figure 36H In the embodiment, dielectric layer 3632 is configured such that dielectric layer 3632 is in contact with protective layer 3608, metal layer 3612, dielectric layer 3614, resistive layer 3622, and dielectric layer 3624. In some cases, dielectric layer 3632 is formed of the same material as dielectric layer 3624 and / or 3614. Figure 36I , the resistive layer 3622 and the dielectric layer 3624 are etched to expose the resistive layer 3622. A block 3634 identifies a portion of the resistive layer 3622 and the dielectric layer 3624 that is not removed after etching. In some cases, the block 3634 may represent a mask material used to facilitate patterning and etching to obtain the resistive layer 3622 and the dielectric layer 3624, such as Figure 36I As shown. Figure 36J In the embodiment, the leg metal layer 3636 is configured to contact the dielectric layer 3632, the resistive layer 3622, and the dielectric layer 3624. The portion of the leg metal layer 3636 on the resistive layer 3622 may be referred to as a resistive layer contact (e.g., a thermistor contact). The leg metal layer 3636 may be made of, for example, titanium, tungsten, copper, or other metals. Figure 36K , dielectric layer 3638 is disposed on leg metal layer 3636. In one aspect, dielectric layer 3638 can be deposited using a very thin sheet-like film, such as atomic layer deposition (ALD).

[0224] exist Figure 36L In FIG. 3 , portions of protective layer 3608, dielectric layer 3632, leg metal layer 3636, and dielectric layer 3638 are etched. In some cases, performing metal etching and oxide etching may be performed alternately, as appropriate, to etch layers 3632, 3636, and 3638 at a time. Block 3640 identifies portions of layers 3608, 3632, 3636, and 3638 that remain after etching. In some cases, block 3640 may represent a method for facilitating patterning and etching to obtain Figure 36L In one aspect, various patterning and etching operations are performed to form bridge 3644. Figure 36M , portions of layers 3608, 3632, 3636, and 3638 are etched. Block 3642 identifies portions of layers 3608, 3632, 3636, and 3638 that remain after etching. In some cases, block 3642 may represent a method for facilitating patterning and etching to obtain Figure 36M The masking materials of layers 3608, 3632, 3636 and 3638 are shown in FIG. Figure 36L and 36M Helps to limit Figure 36N In one aspect, Figure 36L Related to opening / cutting the bottom of the leg structure, Figure 36M Has to do with opening / cutting the top of the leg structure.

[0225] exist Figure 36N and 37 , various operations are performed to form contacts 3648 (e.g., basket contacts) between pads 3604 and vertical legs 3647. A drilling operation can be performed to open a trench (e.g., also referred to as an opening) through release layer 3606 to readout circuit wafer 3600. In some cases, the drilling operation may include an etching operation. Contacts 3648 and vertical legs 3646 together connect bridge 3644 to substrate 3601 (e.g., ROIC). Contacts 3648 can be made of, for example, aluminum. Various material deposition operations (e.g., basket metal deposition operations), patterning operations, etching operations, and / or other operations are performed to obtain Figure 36N The etching operation results in the formation of tails 3650 and 3652 (e.g., also referred to as residual pieces). Tail portions 3650 and 3652 are portions of protective layer 3608 that remain after etching, while portions of metal layer 3612 (previously disposed on tail portions 3650 and 3652) have been removed as a result of the etching operation. Figure 36N In FIG, gaps 3654 and 3656 are above tail portions 3650 and 3652, respectively. Tail portions 3650 and 3652 of protective layer 3608 face dielectric layer 3632. Figure 36N and 37 , a sensing portion of bridge 3644 is associated with region 3666, and a non-sensing portion of bridge 3644 is associated with region 3668 surrounding region 3666. In some embodiments, bridge 3644 may include a metal layer (e.g., an absorber layer) disposed on dielectric layer 3638. A capping layer (e.g., SiO2) may be disposed on the metal layer.

[0226] Figures 38A to 38D A cross-sectional side view is shown relating to an example process for forming contacts according to one embodiment. The contacts can be used to couple a bridge to a readout circuit die. Figures 38A to 38D The various features can be Figures 36A-36N and / or corresponding features in other figures are implemented in the same or similar manner.

[0227] exist Figure 38A In one aspect, a structure having a bridge 3844 is formed. Figure 38A The structure can be used as a starting structure before forming contacts to connect the bridge 3844 to the readout circuit chip. The readout circuit chip includes a substrate 3801, a cover glass layer 3802, and a metal layer 3803. The pad 3804 is arranged on the readout circuit chip. The structure further includes a release layer 3806 (e.g., polyimide), a protective layer 3808, a metal layer 3812 (e.g., a MUP layer formed of titanium), a dielectric layer 3614 (e.g., oxide), a resistive layer 3822 (e.g., VO x layer) and dielectric layer 3838 (e.g., a thin film). Notably, this structure directly connects the bridge 3844 to the readout circuit chip without utilizing a leg structure. In one aspect, in Figure 38D In subsequent processing steps, legs can be selectively defined to connect the bridge 3844 to the readout circuit wafer. If a leg structure is to be formed, the metal layer 3818 can be utilized as a leg metal layer.

[0228] exist Figure 38B In FIG. 38, dielectric layer 3838 is etched. Block 3846 identifies a portion of dielectric layer 3838 that is etched. In some cases, block 3846 may represent a mask material used to facilitate patterning and etching to obtain a pattern such as FIG. Figure 38B The dielectric layer 3838 is shown. Figure 38C3850, portions of release layer 3806, protective layer 3808, metal layer 3812, dielectric layer 3814, and metal layer 3818 are removed to define trench 3850. Layers 3806, 3808, 3812, 3814, 3818, and 3838 may be etched using one or more etching operations. Block 3848 identifies portions of layers 3806, 3808, 3812, 3814, 3818, and 3838 that are etched. In some cases, block 3848 may represent one or more masking materials used to facilitate patterning and etching to obtain Figure 38C In one aspect, metal layer 3812 and / or metal layer 3818 can be used as a hard mask for etching release layer 3806 (e.g., polyimide etching). Figure 38D In the embodiment, a contact metal layer 3852 is arranged. The contact metal layer 3852 is arranged on at least one pad 3804 (eg, Figure 38D The left pad in the figure is used to connect the bridge 3844 to the readout circuit chip. The contact metal layer 3852 contacts the release layer 3806, the protective layer 3808, the dielectric layer 3814, the metal layer 3812, the metal layer 3818, the dielectric layer 3838 and one of the pads 3804. Figures 38A-38D Basket contacts are formed in the embodiment, but in other embodiments, stud contacts or other types of contacts can be formed. Figure 38D The structure shown in FIG38 is subjected to additional operations (such as removing the release layer 3806) to form a thermal radiation meter. Figure 38D The structure of the invention defines legs so that the bridge 3844 is connected to the readout circuit chip by the legs. Other embodiments of the operation, including the formation of the legs, are related to Figures 39A to 39D Description.

[0229] Figures 39A to 39D A cross-sectional side view is shown relating to an example process for forming legs after contact formation to a readout circuit wafer according to one embodiment. Figure 40 According to one embodiment, Figure 39D The cross-sectional side view corresponds to the top view. Figures 39A to 39D The various features can be Figures 36A-36N and / or other figures are implemented in the same or similar manner. Figures 39A to 39D The process of forming Figure 34 and 35 Thermal radiation meter.

[0230] exist Figure 39AIn the embodiment, a structure having a bridge 3944 and a contact metal layer 3922 for connecting the bridge 3944 to the readout circuit chip is formed. In one aspect, Figure 39A The structure can be used as a starting structure before forming the legs for connecting the bridge 3944 to the readout circuit chip. The readout circuit chip includes a substrate 3901, a cover glass layer 3902, and a metal layer 3903. The pad 3904 is arranged on the readout circuit chip. The structure further includes a release layer 3906 (e.g., polyimide), a protective layer 3908 (e.g., a polycap layer), a metal layer 3910 (e.g., formed of titanium), a dielectric layer 3912 (e.g., a nitride (such as Si3N4) or an oxide (such as SiO2)), a resistive layer 3914 (e.g., VO x ), a leg metal layer 3916, a dielectric layer 3918 (such as a thin film layer formed by SiO2 or Si3N4) and a semiconductor layer 3920. Figure 39B , the contact metal layer 3922 is etched. Block 3924 identifies a portion of the contact metal layer 3922 that remains after etching. In some cases, the block 3924 may represent a mask material used to facilitate patterning and etching to obtain Figure 39B The contact metal layer 3922 is shown in FIG.

[0231] exist Figure 39C In the embodiment, a portion of each of the dielectric layer 3918, the leg metal layer 3916, the protective layer 3908, and the release layer 3906 is etched to define a trench 3926. Block 3928 identifies Figure 39C In some cases, block 3928 may represent a process for facilitating patterning and etching to obtain Figure 39C The mask material of the structure shown. Figure 39D and 40 , dielectric layer 3918 and leg metal layer 3916 are etched to expose semiconductor layer 3920, and release layer 3906 is removed. Thus, legs 3931, 3932, and 3930 are formed. Legs 3931 and 3932 are associated with the current pixel (e.g., bridge 3944). Leg 3930 may be associated with the next pixel.

[0232] Figure 39E Shown in Figure 39D An enlarged view of a portion 3934 of the structure. In particular, the portion 3934 is a portion of a leg of the structure. It should be noted that Figure 39EThe materials identified are provided by way of non-limiting example. The leg includes a vertically stacked arrangement of a semiconductor layer 3920 (e.g., Si, polystyrene), a leg metal layer 3916, and a dielectric layer 3918 (e.g., SiO2). Layers 3920, 3916, and 3918 are disposed on a metal layer 3910. The metal layer 3910 is disposed on a protective layer 3908.

[0233] Figures 41A to 41T A cross-sectional side view is shown relating to an example process for forming a bolometer according to one embodiment. Figure 42 According to one embodiment, Figure 41T The cross-sectional side view corresponds to the top view. Figures 41A to 41T The various features can be Figures 36A-36N and / or corresponding features in other figures are implemented in the same or similar manner.

[0234] exist Figure 41A In the embodiment, a readout circuit chip 4100 (e.g., ROIC chip) is provided. The readout circuit chip 4100 includes a substrate 4101, a cover glass layer 4102, and a metal layer 4103. A thermal radiation meter process is performed on the readout circuit chip 4100 to form a thermal radiation meter connected to the readout circuit chip 4100. Figures 41B to 41T , describes an embodiment of a bolometer process. Figure 41B In FIG, pads 4104 are arranged on the readout circuit wafer 4100. Pads 4104 may form part of one or more metal layers. Figure 41C , a release layer 4106 is disposed on the dielectric layer 4102 and the pad 4104, and a protective layer 4108 is disposed on the release layer 4106. In some aspects, one or more alignment marks can be etched in the protective layer 4108 (e.g., to facilitate alignment for a thermal radiometer process using one or more masks). Figure 41D In FIG, a metal layer 4112 (eg, a metal absorption layer) is disposed on the protective layer 4108, and a dielectric layer 4114 (eg, Si3N4 / SiO2) is disposed on the metal layer 4112. Figure 41E In the embodiment, protective layer 4108, metal layer 4112, and dielectric layer 4114 are etched. Patterning may include depositing a photoresist layer and appropriately exposing the photoresist layer to define portions of protective layer 4108, metal layer 4112, and dielectric layer 4114 to be etched. Block 4116 may identify portions of layers 4108, 4112, and 4114 that remain after etching. In some cases, such as Figure 41E As shown, block 4116 may represent a mask material used to facilitate patterning and etching to obtain layers 4108 , 4112 , and 4114 .

[0235] exist Figure 41FIn FIG. 4 , a dielectric layer 4118 (e.g., a thin film oxide layer) and a metal layer 4120 are arranged, and the metal layer 4120 is etched. Blocks 4121 may identify portions of the metal layer 4120 that remain after etching. In some cases, blocks 4121 may represent masking materials used to facilitate patterning and etching to obtain the metal layer 4120, such as Figure 41F As shown. Figure 41G In the embodiment, a dielectric layer 4122 (eg, a thin film oxide layer), a resistance layer 4124 (eg, a VO x layer) and dielectric layer 4126. Dielectric layer 4122 is in contact with dielectric layer 4118, metal layer 4120, and resistive layer 4124. Dielectric layer 4126 is in contact with resistive layer 4124. Figure 41H , the resistive layer 4124 and the dielectric layer 4126 are etched. Such etching can help define the bridge portion of the thermal bolometer to be formed. Block 4128 can identify the portions of the resistive layer 4124 and the dielectric layer 4126 that remain after etching. In some cases, block 4128 can represent a mask material used to facilitate patterning and etching to obtain the resistive layer 4124 and the dielectric layer 4126, such as Figure 41H As shown. Block 4128 can be considered as defining the sensing portion of the bridge and the non-sensing portion of the bridge. Figure 41I 4106, 4118, and 4122 to form trenches 4132 down to the readout circuit wafer 4100. In one aspect, the process of defining trenches 4132 (and, in some cases, trenches associated with other pixels of the thermal bolometer) can be referred to as reticulated patterning. Block 4130 can identify portions of layers 4122, 4118, and 4106 to be removed to form trenches 4132.

[0236] exist Figure 41J In the embodiment, a contact metal layer 4134 is arranged. The contact metal layer 4434 is arranged on at least one pad 4104 (eg, Figure 41J 4104) to connect the bridge portion of the thermal radiation meter to the readout circuit chip 4100. The contact metal layer 4134 contacts the release layer 4106, the dielectric layer 4118, the dielectric layer 4122 and the at least one pad 4104. The contact metal layer 4134 is used to form a contact basket. Figure 41K , contact metal layer 4134 is etched to expose dielectric layers 4126 and 4122. Block 4136 may identify a portion of contact metal layer 4134 that is removed by etching. In some cases, block 4136 may represent a mask material used to facilitate patterning and etching to obtain contact metal layer 4134, such as Figure 41K As shown. Figure 41LIn the case of a dielectric layer 4138, a dielectric layer 4138 is arranged. Figure 41M , dielectric layer 4138 is etched. Block 4140 may identify a portion of dielectric layer 4138 that remains after etching. In some cases, block 4140 may represent a mask material used to facilitate patterning and etching to obtain dielectric layer 4138, such as Figure 41M As shown. Figure 41N , contact metal layer 4134 is etched. Block 4142 may identify a portion of contact metal layer 4134 that remains after etching. In some cases, block 4142 may represent a mask material used to facilitate patterning and etching to obtain Figure 41N Contact metal layer 4134 is shown.

[0237] exist Figure 41O In FIG. 4 , dielectric layer 4138, dielectric layer 4126, and resistive layer 4124 are etched to expose resistive layer 4124. Block 4144 may identify portions of layers 4138, 4126, and 4124 that are removed after etching. In some cases, block 4144 may represent a process for facilitating patterning and etching to obtain Figure 41O The masking materials of layers 4138, 4126 and 4124 are shown in FIG. Figure 41P In the embodiment, a support metal layer 4146 is arranged. Figure 41Q In the embodiment, the leg metal layer 4146 is etched. Block 4148 may identify portions of the leg metal layer 4146 that remain after etching. In some cases, block 4148 may represent a method for facilitating patterning and etching to obtain Figure 41Q The mask material of the leg metal layer 4146 is shown in FIG. Figure 41R In the embodiment, a dielectric layer 4150 (eg, a thin film layer) is arranged.

[0238] exist Figure 41S , portions of dielectric layer 4112, dielectric layer 4114, dielectric layer 4118, dielectric layer 4122, metal layer 4120, leg metal layer 4146, and dielectric layer 4150 are removed to form bridge 4153. Block 4152 may identify portions of layers 4112, 4114, 4118, 4122, 4120, 4146, and 4150 that remain after etching. In some cases, block 4152 may represent masking material used to facilitate patterning and etching to obtain layers 4112, 4114, 4118, 4122, 4120, 4146, and 4150, such as Figure 41S As shown. Figure 41T and 42 In the embodiment, one or more patterning operations and etching operations are performed, and the release layer 4106 is removed to form Figure 41TThe bolometer includes a bridge 4153 and legs 4160 and 4161. The etching operation results in the formation of tails 4154, 4156, and 4158. The etching operation results in the formation of tails 4154, 4156, and 4158 and gaps 4162, 4164, and 4166 above the tails 4154, 4156, and 4158, respectively. Figure 41T and 42 4, a sensing portion of bridge 4153 is associated with region 4170, and a non-sensing portion of bridge 4153 is associated with region 4172 surrounding region 4170. In some embodiments, bridge 4153 can include a metal layer (e.g., an absorber layer) disposed on dielectric layer 4126. A cap layer can be disposed on the metal layer.

[0239] Figure 43A and 43B A view related to a bolometer 4300 having a bridge 4305, vertical legs 4308 and 4310, and contacts 4315 and 4320 is shown according to one embodiment. Figure 43A It is a perspective view of the thermal radiation meter 4300. Figure 43B A cross section of the bolometer 4300 is shown along line 4325. In this regard, the cross section shows a portion 4330 of the bolometer 4300 along line 4325. In some embodiments, the bolometer 4300 can be formed using the same or similar techniques as those provided herein. Figure 43B As shown, the thermal radiation meter 4300 includes a dielectric layer 4335 (eg, an insulator), a metal layer 4340 (eg, titanium), a dielectric layer 4345 (eg, an insulator), a resistive layer 4350 (eg, VO x ), leg metal layer 4355 (e.g., titanium, copper), dielectric layer 4360 (e.g., a thin insulator / oxide layer formed of Si3N4), dielectric layer 4365 (e.g., Si3N4), and dielectric layer 4370 (e.g., SiO2). Dielectric layer 4335 can be referred to as a protective layer.

[0240] Metal layer 4340 is disposed on dielectric layer 4335. Dielectric layer 4345 is disposed on metal layer 4340. Resistive layer 4350 is disposed on dielectric layer 4345. Dielectric layer 4370 is disposed on resistive layer 4350. Leg metal layer 4355 is disposed on resistive layer 4350. Dielectric layer 4360 is disposed on leg metal layer 4355. Dielectric layer 4370 contacts leg metal layer 4355 and resistive layer 4350. Contact 4315 includes basket fill layer 4375, leg metal layer 4355, dielectric layer 4365, dielectric layer 4345, cap layer 4335, and leg metal layer 4380. Contact 4320 includes a basket fill layer 4385, a metal layer 4355, a dielectric layer 4365, a dielectric layer 4345, a cap layer 4335, and a leg metal layer 4390. Basket fill layers 4375 and 4385 can be made of, for example, aluminum. Leg metal layers 4380 and 4390 can be made of, for example, titanium, tungsten, copper, or other metals. Dielectric layers 4365 and 4345 can serve as passivation layers for contacts 4315 and 4320. Although Figure 43A Contacts 4315 and 4320 are shown as being basket-shaped contacts, but in other embodiments, contacts 4315 and / or 4320 may be implemented using differently shaped contacts and / or different types of contacts (eg, stud contacts).

[0241] In some aspects, such as Figure 43B As shown, the etching operation performed to obtain the bolometer 4300 forms tail portions 4391 and 4393 of the dielectric layer 4335. In this regard, the tail portions 4391 and 4393 still exist after etching, while portions of the metal layer 4340 (previously disposed on the tail portions 4391 and 4393 before being etched) have been removed to form voids 4392 and 4394 above the tail portions 4391 and 4393.

[0242] The resistive layer 4350 is coupled to the contacts 4315 and 4320 via the vertical legs 4308 and 4310. In this regard, the leg metal layer 4355 of the vertical legs 4308 and 4310 is in contact with the resistive layer 4350. By way of non-limiting example, the resistive layer 4350 may include VO x 、TiO x Or amorphous silicon. Vertical legs 4308 and 4310 connect to bridge 4305 and contacts 4315 and 4320. Leg metal layers 4380 and 4390 of contacts 4315 and 4320, respectively, connect to a substrate (e.g., ROIC). Thus, bridge 4305 is coupled to the substrate via vertical legs 4308 and 4310 and contacts 4315 and 4320. Contacts 4315 and 4320 may contact (e.g., physically contact) the metal layer of the substrate. In some cases, the substrate may have a cover glass layer formed thereon.

[0243] As a non-limiting example, the thicknesses of cap layer 4335, metal layer 4340, dielectric layer 4345, resistor layer 4350, metal layer 4355, dielectric layer 4360, dielectric layer 4370, and dielectric layer 4365 are 250 angstroms, 300 angstroms, 750 angstroms, 600 angstroms, 300 angstroms, 300 angstroms, 300 angstroms, and 500 angstroms, respectively. Distance D refers to the distance between the bottom surface of cap layer 4335 and the bottom surface of leg metal layer 4390. A non-limiting example of distance D can be approximately 1.5 microns. As a non-limiting example, the width W and height H of the vertical legs can be approximately 0.24 microns and 0.25 microns, respectively.

[0244] Figures 44A to 44E Various views are shown relating to a bolometer 4400 having a bridge 4405, vertical legs 4408 and 4410, and contacts 4415 and 4420, according to one embodiment. Figure 44A A perspective view of a bolometer 4400 is shown. Figure 44B Shown is an enlarged view of a portion 4424 of the bolometer 4400. The portion 4424 shows the connection of the vertical legs 4410 to the bridge 4405. Figure 44C A side view cross section of bolometer 4400 along line 4425 is shown. Figure 44D Shown Figure 44C An enlarged view of a portion 4404 of the side cross section. Figure 44E yes Figure 44C 4406. The bolometer 4400 includes a cap layer 4435.

[0245] The bolometer 4400 includes a cap layer 4435 (e.g., a polyester cap), a metal layer 4440 (e.g., titanium), a dielectric layer 4445 (e.g., Si3N4), a dielectric layer 4460, a dielectric layer 4461, a dielectric layer 4462, a resistor layer 4450 (e.g., VO x ), a leg metal layer 4455 (eg, titanium), a dielectric layer 4465 (eg, Si3N4), and a dielectric layer 4470 (eg, VO formed of SiO2 x In one aspect, dielectric layers 4460, 4461, 4462, and 4460 can be thin dielectric layers, such as a thin layer of Si3N4. Contact 4415 includes a basket liner layer 4480. Contact 4420 includes a basket liner layer 4490.

[0246] At portion 4404 of bridge 4405, Figure 44C and 44DThe cross-sectional view shows that metal layer 4440 is disposed on cap layer 4435. Dielectric layer 4445 is disposed on metal layer 4440. Dielectric layer 4461 is disposed on dielectric layer 4445. Dielectric layer 4462 is disposed on dielectric layer 4461. Resistive layer 4450 is disposed on dielectric layer 4462. Dielectric layer 4470 is disposed on resistive layer 4450. Dielectric layer 4465 is disposed on dielectric layer 4470 and dielectric layer 4462. Dielectric layer 4460 is disposed on dielectric layer 4465.

[0247] At portion 4406 of vertical leg 4410, Figure 44C and 44E (and further described below Figure 45F ) shows a cross-sectional view of dielectric layer 4462 disposed on dielectric layer 4461. Leg metal layer 4455 is disposed on dielectric layer 4462 and is surrounded on at least two opposing sides by dielectric layers 4460 and 4462. Vertical leg 4410 has a tail portion 4464 of dielectric layer 4461. A gap 4492 is provided between tail portion 4464 and one side of dielectric layer 4462 such that tail portion 4464 faces dielectric layer 4462. In some aspects, for example, Figure 44A and 44B As shown, ridges or steps can be formed in dielectric layer 4460, formed by the connection of legs 4410 to bridge 4405, which adds structural support. In this regard, various steps can be included in bridge 4405 to improve the structural integrity of bridge 4405.

[0248] For example, Figure 44E As shown, vertical leg 4410 has an S-shaped (e.g., also considered a Z-shaped or serpentine) cross-section formed by leg metal layer 4455 surrounded by dielectric layers 4460 and 4462 (e.g., passivated), with tail 4464 forming a residual piece of dielectric layer 4461. In this regard, vertical leg 4410 has a bottom horizontal segment 4468, a top horizontal segment 4469, and a middle vertical segment 4466 between bottom horizontal segment 4468 and top horizontal segment 4469 (e.g., adjacent to the bottom horizontal segment), which together define the S-shaped cross-section. Bottom horizontal segment 4468 is substantially perpendicular to middle vertical segment 4466 and substantially parallel to top horizontal segment 4469. Top horizontal segment 4469 is substantially perpendicular to middle vertical segment 4466. In certain aspects, two segments / portions may be referred to as being substantially perpendicular if the angle between them is within ±10° of 90°. In certain aspects, two segments / portions may be referred to as being substantially parallel if the angle between the two segments / portions is within ±10° of 0°.

[0249] A dielectric layer 4460 is formed on a first sidewall of the leg metal layer 4455 and a first side of the leg metal layer 4455. A dielectric layer 4462 is formed on a second sidewall of the leg metal layer 4455 and a second side of the leg metal layer 4455. The first sidewall is opposite the second sidewall, and the first side is opposite the second side. The first sidewall is substantially perpendicular to the first side. The second sidewall is substantially perpendicular to the second side. The vertical leg 4406 (e.g., each segment thereof) has: a first dimension extending in a first direction, the first direction being substantially perpendicular to a plane defined by a surface of a substrate (e.g., substrate 4101); and a second dimension extending in a second direction, the second direction being substantially parallel to the plane. In some aspects, at least as Figure 44C and 44E As shown, in middle vertical segment 4466, a first dimension of vertical leg 4406 (e.g., a dimension along the z-direction) is greater than a second dimension of vertical leg 4406 (e.g., a dimension along the x-direction or the y-direction). In this regard, in middle vertical segment 4465, a first dimension of leg metal layer 4455 is greater than a second dimension of leg metal layer 4455, a first dimension of dielectric layer 4460 is greater than a second dimension of dielectric layer 4460, and a first dimension of dielectric layer 4462 is greater than a second dimension of dielectric layer 4462. In bottom horizontal segment 4468 and top horizontal segment 4469, a first dimension of vertical leg 4406 is less than a second dimension of vertical leg 4406. In this regard, the first dimensions of leg metal layer 4455, dielectric layer 4460, and dielectric layer 4462 are less than the second dimensions of leg metal layer 4455, dielectric layer 4460, and dielectric layer 4462, respectively.

[0250] Figures 45A to 45F A cross-sectional side view is shown relating to an example process of forming a bolometer 4400 according to one embodiment. Figures 46A to 46F A top view is shown in relation to an example process according to one embodiment. A cross-sectional side view is taken along Figure 44A Line 4425. Figure 45A In the embodiment, a release layer 4505 (eg, polyimide) is deposited (eg, on a substrate ( Figure 45A (not shown)). A cap layer 4435 is deposited on the release layer 4505, a metal layer 4440 is deposited on the cap layer 4435, and a dielectric layer 4445 is deposited on the metal layer 4440. Figure 45B and 46A In the embodiment, a dielectric layer 4461 is disposed (e.g., using a thin film deposition). A metal layer 4542 (e.g., a sacrificial metal layer) is disposed on the dielectric layer 4461 and etched. Figure 45C and 46B, dielectric layer 4462 is disposed (e.g., using thin film deposition) over dielectric layer 4461 and metal layer 4542. Resistive layer 4450 is deposited and patterned / etched over dielectric layer 4462. Dielectric layer 4470 is disposed over resistive layer 4450. Figure 47A and 47B Shown Figure 45C An enlarged view of portions 4502 and 4504.

[0251] exist Figure 46C In , trenches 4615 and 4620 are formed for forming contacts 4415 and 4420, respectively. Metal layer 4605 is deposited and then etched away from the portion forming bridge 4405 of bolometer 4400. In Figure 45D and 46D In , basket liner layers 4480 and 4490 are arranged, and dielectric layer 4465 is deposited and etched. The basket is patterned and portions 4620 and 4625 are etched to form contacts to resistive layer 4450. Figure 45E and 46E In FIG, the leg metal layer 4455 is deposited and partially etched away. In this regard, a portion of the leg metal layer 4455 remains on portions 4620 and 4625 of the resistive layer 4450. The leg metal layer 4455 is disposed on the basket liner layers 4480 and 4490. Figure 45F and 46F In the embodiment, dielectric layer 4460 is deposited, leg metal layer 4455 is cut to form vertical legs 4408 and 4410, metal layer 4542 is removed, and release layer 4505 is removed to release bridge 4405 and vertical legs 4408 and 4410. It should be noted that Figure 45F Shown Figure 44C It is further noted that, Figure 46F Shown with Figure 44A Same stereogram.

[0252] In some embodiments, the bolometer may have a thermal conductivity that is not provided by the bolometer including a resistive layer (eg, VO x) defined by multiple portions of the bolometer. In some aspects, the perforations defined by the bolometer are along the same plane / layer of the bolometer's legs and bridge. The size of the perforations can appropriately reduce the thermal mass associated with the bolometer while maintaining the IR sensing capability and structural integrity of the bolometer. In this regard, the perforations can reduce the thermal mass while allowing the bolometer to capture incident photons having wavelength components within a desired wavelength range. The reduced thermal mass can enable faster cooling and heating of the bolometer. In some aspects, such a bolometer can include the vertical legs described herein for connecting the bolometer's bridge and readout circuitry (e.g., ROIC). In other aspects, such a bolometer does not utilize vertical legs to connect the bolometer's bridge and readout circuitry.

[0253] Figure 48 is a flow chart illustrating operations that may be used to form a thermal bolometer according to one embodiment. In some embodiments, a thermal bolometer may be related to, for example, Figure 29 、 32 , 34, 36N, 37, 39D, 40, 41T, 42, 43A, 43B and 44A-44E. As a non-limiting example, the flow chart is about Figures 41A to 41T One or more of the descriptions.

[0254] At block 4805, a bridge structure is formed on the sacrificial layer. Figure 41S and 41T , the bridge structure may include a bridge 4153, and the sacrificial layer may include a release layer 4106. The bridge 4153 includes a protective layer 4108, a metal layer 4112 (e.g., a metal absorption layer), a dielectric layer 4114, a dielectric layer 4118 (e.g., a thin film oxide layer), a dielectric layer 4122 (e.g., a thin film oxide layer), a resistive layer 4124, and a dielectric layer 4150 (e.g., a thin film layer). In some portions of the bridge 4153, a leg metal layer 4146 is disposed on the resistive layer 4124 (e.g., to facilitate coupling the bridge 4153 to the substrate 4101 via the leg 4160). In some portions of the bridge 4154, a cap layer (e.g., VO) is disposed on the resistive layer 4124. x cap).

[0255] At block 4810, an opening is formed in a sacrificial layer. Figure 41I , the opening can be trench 4132. At block 4815, a contact metal layer is disposed on the sidewalls of the opening. For example, referring to Figures 41J to 41N , the contact metal layer may be the contact metal layer 4134. Figures 41J to 41N As shown, a layer of contact metal material may be deposited and suitably etched.

[0256] At block 4820, a leg structure is formed. The leg structure couples the bridge structure to the contact metal layer. For example, referring to Figure 41T , the leg structure may include a leg 4160 that couples the bridge 4153 to the contact metal layer 4134. The leg 4160 includes a dielectric layer 4118, a dielectric layer 4122, a leg metal layer 4146, and a dielectric layer 4150. Different portions of the leg 4160 may have a Z-shaped cross-section (e.g., Figure 41T the rightmost portion of the middle leg 4160) or an S-shaped section (e.g., Figure 41T The leg 4160 has tail portions 4154, 4156, and 4158 and gaps 4162, 4164, and 4166 above the tail portions 4154, 4156, and 4158, respectively.

[0257] At block 4825 , the sacrificial layer is removed to release the bridge structure and the leg structure. After removing the sacrificial layer, the bridge structure and the leg structure are suspended above the substrate 4101 .

[0258] It should be pointed out that Figure 48 The flowchart of FIG48 illustrates the formation of a thermal bolometer. In some cases, one or more additional thermal bolometers may be formed along with (e.g., simultaneously with) the formation of the thermal bolometer. For example, a plurality of bridge structures may be formed on a sacrificial layer at block 4805, a plurality of openings may be formed in the sacrificial layer at block 4810, and so on.

[0259] Figure 49 A perspective view of a bolometer 4900 is shown according to one embodiment. Figure 50 A top view of a thermal bolometer 4900 according to one embodiment is shown. Dielectric layer 4906 may be a thin film layer formed of Si3N4. Thermal bolometer 4900 includes: a bridge 4905; vertical legs 4908 and 4910 and contacts 4915 and 4920. Bridge 4905 includes a sensing portion 4906 and a remaining portion 4907 (e.g., also referred to as a non-sensing portion). Sensing portion 4906 is a portion of bridge 4905 that includes a resistive layer (e.g., VO x Layer). Remaining portion 4907 is a portion of bridge 4905 and does not include the resistive layer. Remaining portion 4907 surrounds sensing portion 4906. Remaining portion 4907 has perforations as defined herein, with perforation 4909 being designated. Vertical leg 4908 is connected to sensing portion 4906 of bridge 4905 via leg / bridge contact 5014. Vertical leg 4910 is connected to sensing portion 4906 of bridge 4905 via leg / bridge contact 5013. Contact 4915 comprises basket backing layer 4980. Contact 4920 comprises basket backing layer 4990.

[0260] Figures 51A to 51C Other examples of thermal radiation meters according to one or more embodiments are shown. In particular, Figure 51A 、 51B 51C and 51C show top views of thermal bolometers 5100, 5130, and 5160, respectively. Figure 51A The bolometer 5100 includes a bridge 5105 having a sensing portion 5106 and a non-sensing portion 5107, vertical legs 5108 and 5110, leg / bridge contacts 5113 and 5114, and contacts 5115 and 5120. The non-sensing portion 5107 includes perforations, one of which 5109 is labeled. Figure 51B The bolometer 5130 includes a bridge 5135 having a sensing portion 5136 and a non-sensing portion 5137, vertical legs 5138 and 5140, leg / bridge contacts 5143 and 5144, and contacts 5145 and 5150. The non-sensing portion 5137 includes perforations, one of which 5139 is labeled. Figure 51C The bolometer 5160 includes a bridge 5165 having a sensing portion 5166 and a non-sensing portion 5167, vertical legs 5168 and 5170, leg / bridge contacts 5173 and 5174, and contacts 5175 and 5170. The non-sensing portion 5167 includes perforations, one of which 5169 is labeled.

[0261] like Figure 50 and 51A As shown in FIG. 51C , the bolometer can have different structural features to achieve desired performance. As non-limiting examples, such structural features include the number of bends in the legs (e.g., vertical legs), the size of the legs, the material used to form the legs, the number of perforations in the non-sensing portion of the bridge, and the arrangement of the perforations.

[0262] Figure 52 5206 and a non-sensing portion 5207 (e.g., VO x ). Figure 53A cross-sectional side view of a portion of a bolometer having a perforation defined therein according to one embodiment is shown. The bolometer includes a bridge 5305 and a leg 5310 coupled to the bridge 5305. The bridge 5305 includes a sensing portion 5306 having a thermistor and a non-sensing portion 5307 without the thermistor. The thermistor may be disposed on a first insulator. The second insulator may be disposed on the thermistor. The absorber layer may be disposed on the second insulator. The third insulator may be disposed on the metal layer. Each of the first insulator, the second insulator, or the third insulator may include one or more insulator layers. Alternatively or in addition Figure 53 In addition to the absorber layer shown, the absorber layer may be arranged between the insulator layers of the first insulator.

[0263] Through-holes 5309 and 5311 are formed in the non-sensing portion 5307. Through-holes 5309 and 5311 can be formed using one or more etching operations. In some aspects, each etching operation can be implemented using a different etching chemistry (e.g., depending on the material to be etched). In some embodiments, Figure 52 The bolometer may have a perforation formed in the non-sensing portion 5207 to reach Figure 53 In one instance, each layer of material may be formed with perforations defined therein. For example, a first layer of material may be formed with perforations defined therein. A second layer of material may then be formed over the first layer of material, with the second layer of material having perforations defined therein that are appropriately aligned with the perforations of the first layer of material. In another instance, Figure 52 The thermal radiation meter then forms a perforation through all the insulators of the non-sensing portion 5207.

[0264] Figure 54 is a flow chart illustrating operations that may be used to form a bolometer having a through-hole defined therein according to one embodiment. In some embodiments, the bolometer may be related to, for example, Figure 49 、 51A - Any of the thermal radiation meters described in 51C and 53.

[0265] At block 5405, a bridge structure is formed. In some embodiments, this can be accomplished by performing a process similar to Figure 25 In some cases, you can perform Figure 25 Some or all of the blocks shown in can be used to form a bridge structure.

[0266] At block 5410, a leg is formed for connecting the bridge structure to the readout circuit. In some aspects, the leg is a vertical leg, as described with reference to one or more embodiments. In some cases, the vertical leg can be formed at the same time as the bridge structure is formed. In some embodiments, the vertical leg can be formed by performing a process similar to Figure 20-22 One or more of the operations provided are used to form the legs.

[0267] At block 5415, perforations are formed in the bridge structure to obtain a microbolometer bridge. The perforations can be formed using one or more etching operations. In some aspects, each etching operation can be implemented using a different etching chemistry (e.g., depending on the material to be etched). Alternatively, perforations can be formed in each layer. In this case, semiconductor processing techniques are performed to directly form the microbolometer bridge (e.g., without having to completely form the bridge structure without the perforations and then forming the perforations in the bridge structure). For example, a first layer of material can be formed with a perforation defined therein. A second layer of material can then be formed over the first layer of material, wherein the second layer of material has a perforation defined therein that is appropriately aligned with the perforation of the first layer of material.

[0268] Please note that Figure 54 One or more operations can be combined, omitted, and / or performed in a different order as desired. For example, the bridge structure, the legs, and / or the perforations in the bridge structure can be formed together and / or as separate processing steps.

[0269] Figures 55A to 55D A cross-sectional side view is shown relating to an example process for forming a bolometer according to one embodiment. Figure 56 shows a method according to an embodiment of the present invention Figure 55D The cross-sectional side view corresponds to the top view. Figures 55A to 55D The various features can be Figures 36A-36N and / or corresponding features in other figures are implemented in the same or similar manner.

[0270] exist Figure 55A The structure includes a substrate, a cover glass layer 5602, a pad 5604, a release layer 5506, a protective layer 5508, a metal layer 5512, a dielectric layer 5514 (eg, Si3N4 / SiO2), a metal layer 5520, a resistor layer 5524 (eg, VO x layer), dielectric layer 5526, contact metal layer 5534 and leg metal layer 5546. The structure also includes a similar Figures 36A-36N other layers in the (e.g., dielectric layers), but in Figure 55A There is no clear indication. Figure 55B In, right Figure 55A The structure is patterned and etched. Figure 55C in Figure 55B A patterning and etching operation is performed on the structure to define a through-hole in the bolometer bridge (eg, a non-sensing portion of the bolometer bridge). Figure 55C 、 55D An example perforation 5550 is shown in FIG. Figure 55D and 56 In, right Figure 55C This operation removes the release layer and forms the tail of the dielectric layer. It is noted that the perforations (including perforation 5550) are shown as having an octagonal shape. More generally, the perforations can have other shapes, such as other polygonal shapes (e.g., rectangular shapes), circular shapes, and / or other shapes. Figures 55A-55D Each of them can be along Figure 56 A cross-sectional side view taken along line 5605 is shown in FIG.

[0271] Thus, a bolometer is provided according to various embodiments. Utilizing the various embodiments, bolometers having various properties can be formed as appropriate for the application. Various example features are provided below. The pixels (e.g., the bolometer and associated legs) have appropriate materials and structures to provide a flat bolometer (e.g., a flat bridge). A flatter bolometer is better able to avoid offsets due to material stress (e.g., relative to an initial plane), avoid stray light, and the like. A merit graph for a bolometer can be based on a noise equivalent temperature difference and a thermal time constant. In one aspect, the merit value is desired to be low. To achieve a low merit value, it is desirable to have a thin bridge and a low thermal time constant. In some cases, the quality factor is proportional to the thermal mass of the bridge and is independent of the thermal conduction of the legs.

[0272] It should be noted that the above description describes a microbolometer with an absorbing layer. One or more absorbing layers may be disposed above the resistive layer, and / or one or more absorbing layers may be disposed below the resistive layer. The absorbing layer may be in contact with the resistive layer, or one or more dielectric layers may be interposed between the absorbing layer and the resistive layer. In some cases, a reinforcing layer may be in contact with the absorbing layer. The reinforcing layer and the absorbing layer may provide enhanced infrared absorption for the microbolometer. By way of non-limiting example, the reinforcing layer may be made of titanium, titanium oxide, Ti, and TiO. x The invention also includes a combination of aluminum, titanium nitride, nickel, iron, zinc, platinum, tantalum, chromium, other transition metals, other metals, alloys of these metals, oxides of these materials, and / or combinations of these metals and their oxides. An embodiment of a microbolometer with an absorption layer and / or enhancement layer can be found in U.S. Patent No. 9,945,729, the entire contents of which are incorporated herein by reference.

[0273] It should be noted that the dimensional aspects provided above are examples, and other values ​​of the dimensions may be utilized according to one or more embodiments. In addition, the dimensional aspects provided above are generally nominal values. As will be understood by those skilled in the art, each dimensional aspect has a tolerance associated with that dimensional aspect. Similarly, the aspects provided above regarding the distances between components are also examples and have associated tolerances. It should also be noted that although the above describes the use of an etching operation to form the through-holes, as will be understood by those skilled in the art, other semiconductor processing techniques suitable for removing material (e.g., drilling operations, laser operations) may also be performed to form the through-holes.

[0274] Where applicable, various embodiments of the present invention may be implemented using hardware, software, or various combinations of hardware and software. Where applicable, the various hardware components and / or software components described herein may be combined into composite components consisting of software, hardware, and / or both, without departing from the scope and functionality of the present invention. Where applicable, the various hardware components and / or software components described herein may be separated into subcomponents consisting of software, hardware, and / or both, without departing from the scope and functionality of the present invention. Where applicable, it is contemplated that software components may be implemented as hardware components, and vice versa.

[0275] Software according to the present invention (such as program code and / or data) can be stored on one or more computer-readable media. It is also contemplated that the software identified herein can be implemented using one or more general or special-purpose computers and / or computer systems, networking, and / or other means. Where applicable, the order of the various steps described herein can be changed, combined into composite steps, and / or separated into sub-steps to provide the functionality described herein.

[0276] While the present invention has been described in detail with respect to only a limited number of embodiments, it should be readily understood that the invention is not limited to these disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, alternatives, or equivalent arrangements not previously described, but which are consistent with the spirit and scope of the invention. Furthermore, while various embodiments of the invention have been described, it should be understood that various aspects of the invention may include only some of the described embodiments. Accordingly, the present invention should not be construed as limited by the foregoing description, but only by the scope of the appended claims.

Claims

1. An infrared imaging device, comprising: a substrate comprising a plurality of contacts and a surface, wherein the surface defines a plane; a microbolometer array coupled to the substrate, wherein the microbolometer array comprises a plurality of microbolometers, and wherein each microbolometer comprises: bridge; and a leg structure coupled to the bridge and one of the plurality of contacts and extending along a path between the bridge and the one of the plurality of contacts in at least a first direction substantially parallel to the plane, wherein: The leg structure includes a cross-section having a first section, a second section, and a third section, the second section being substantially parallel to the first section, and the third section connecting the first section and the second section; The cross section is perpendicular to the direction of the path; The cross section is an S-shaped cross section or a Z-shaped cross section maintained along the path; The leg structure includes a first segment associated with the first section, a second segment associated with the second section, and a third segment associated with the third section and adjacent to the first segment and the second segment; the first segment having a first dimension extending in a first direction and a second dimension extending in a second direction substantially perpendicular to the plane, wherein the first dimension is greater than the second dimension; the third segment having a third dimension extending in the first direction and a fourth dimension extending in the second direction, wherein the third dimension is smaller than the fourth dimension; Each of the first segment, the second segment, and the third segment includes a respective portion of the first metal layer, a respective portion of the first layer, and a respective portion of the second layer; and Each of the first metal layer, the first layer, and the second layer has a cross-section that maintains the same shape as a cross-section of the leg structure along the path.

2. The infrared imaging device according to claim 1, wherein: The first metal layer contacts the resistive layer of the bridge, and wherein the third section is substantially perpendicular to the first section and the second section.

3. The infrared imaging device according to claim 1, wherein: The third section is at an angle relative to the first and second sections.

4. The infrared imaging device according to claim 1, wherein: The first section and the second section extend along the first direction and the third direction substantially parallel to the plane, and The third section connects the first section and the second section in a second direction substantially perpendicular to the plane.

5. The infrared imaging device according to claim 1, wherein: The first layer is formed on a first sidewall of the first metal layer and a first side of the first metal layer, the second layer is formed on the second sidewall of the first metal layer and the second side of the first metal layer, The first side wall is opposite to the second side wall, and The first side is opposite to the second side.

6. The infrared imaging device according to claim 5, wherein: The first sidewall is substantially perpendicular to the first side, and wherein the third segment has a fifth dimension extending in the first direction and a sixth dimension extending in the second direction, and wherein the fifth dimension is greater than the sixth dimension.

7. The infrared imaging device according to claim 5, wherein: A portion of the first layer and a portion of the second layer are separated by a gap, and wherein the portion of the first layer faces the portion of the second layer.

8. The infrared imaging device according to claim 5, further comprising: a contact metal layer coupled to the substrate and the leg structure; as well as a cover glass layer disposed on the substrate; as well as A pad is disposed on the cover glass layer and coupled to the one contact among the plurality of contacts, wherein the contact metal layer contacts the pad.

9. The infrared imaging device according to claim 8, wherein: A portion of the first metal layer is disposed on the contact metal layer, and wherein a portion of the first layer is disposed on the portion of the first metal layer.

10. The infrared imaging device according to claim 5, wherein: The first layer is an oxide layer or a dielectric layer, and wherein the second layer is a semiconductor layer or a dielectric layer.

11. The infrared imaging device according to claim 1, wherein: The bridge comprises: a cap layer facing the substrate; a second metal layer disposed on the cap layer; Resistive layer; a first dielectric layer disposed between the second metal layer and the resistive layer; a second dielectric layer disposed on the resistive layer; and a third dielectric layer disposed on the second dielectric layer, Wherein, the leg structure contacts the third dielectric layer.

12. The infrared imaging device according to claim 11, wherein: The bridge further comprises: a third metal layer disposed on the third dielectric layer; and A fourth dielectric layer is disposed on the third metal layer.

13. The infrared imaging device according to claim 1, wherein: The bridge comprises: a cap layer facing the substrate; Resistive layer; a first dielectric layer disposed between the cap layer and the resistive layer; a second dielectric layer disposed on the resistive layer; a third dielectric layer; and a second metal layer disposed between the second dielectric layer and the third dielectric layer, Wherein, the leg structure contacts the third dielectric layer.

14. The infrared imaging device according to claim 13, wherein: The bridge further includes a fourth dielectric layer disposed on the third dielectric layer, and wherein the leg structure is in contact with the fourth dielectric layer.

15. The infrared imaging device according to claim 13, wherein: The resistive layer is a vanadium oxide layer, and wherein the second dielectric layer is a silicon dioxide layer.

16. The infrared imaging device according to claim 1, wherein: The leg structure and microbolometer bridge are along a common plane.

17. A method of forming an infrared imaging device, the method comprising: forming a bridge on the sacrificial layer; forming an opening in the sacrificial layer; disposing a contact metal layer on the sidewalls of the opening; A leg structure is formed to be connected to the bridge and the contact metal layer, the leg structure extending along a path between the bridge and the contact metal layer in at least a first direction substantially parallel to a plane defined by a surface of a substrate of the infrared imaging device, wherein the leg structure includes a cross-section having a first portion, a second portion, and a third portion, the second portion being substantially parallel to the first portion, and the third portion connecting the first portion and the second portion, wherein the cross-section is perpendicular to the direction of the path; wherein the cross-section is an S-shaped cross-section or a Z-shaped cross-section maintained along the path; wherein the leg structure includes a first segment associated with the first portion, a second segment associated with the second portion, and a third segment associated with the third portion. a third segment associated with and adjacent to the first segment and the second segment; wherein the first segment has a first dimension extending in a first direction and a second dimension extending in a second direction substantially perpendicular to the plane, wherein the first dimension is greater than the second dimension; wherein the third segment has a third dimension extending in the first direction and a fourth dimension extending in the second direction, wherein the third dimension is less than the fourth dimension, wherein each of the first segment, the second segment, and the third segment includes a respective portion of the first metal layer, a respective portion of the first layer, and a respective portion of the second layer, and each of the first metal layer, the first layer, and the second layer has a cross-section that remains the same shape as the cross-section of the leg structure along the path; and The sacrificial layer is removed to suspend the bridge and the leg structure above the substrate, wherein the contact metal layer is coupled to the substrate.

18. The method according to claim 17, wherein The third section is substantially perpendicular to the first section and the second section.

19. The method according to claim 17, wherein The third section is at an angle relative to the first section and the second section.

20. The method of claim 17, wherein: The first section and the second section extend along the first direction and a third direction substantially parallel to the plane, and The third section connects the first section and the second section in a second direction substantially perpendicular to the plane.

21. The method of claim 17, wherein: The first layer is formed on a first sidewall of the first metal layer and a first side of the first metal layer, the second layer is formed on the second sidewall of the first metal layer and the second side of the first metal layer, The first side wall is opposite to the second side wall, and The first side is opposite to the second side.

22. The method according to claim 21, wherein A portion of the first layer and a portion of the second layer are separated by a gap, and wherein the portion of the first layer faces the portion of the second layer.

23. The method according to claim 17, wherein The forming of the bridge comprises: disposing a second metal layer on the cap layer; disposing a first set of dielectric layers on the second metal layer; disposing a resistive layer on the first set of dielectric layers; and disposing a second set of dielectric layers on the resistive layer, Wherein, the leg structure contacts the second set of dielectric layers.

24. The method according to claim 17, wherein The forming of the opening exposes a pad arranged on a cover glass layer of the infrared imaging device, and wherein the cover glass layer is arranged on the substrate.

Images