Thermoelectric-based Infrared Detector having a Cavity and a MEMS Structure Defined by BEOL Metals Lines

• US 20190027522A1
• Filed: 07/19/2017
• Published: 01/24/2019
• Est. Priority Date: 07/19/2017
• Status: Active Grant

• Current Assignee: Meridian Innovation Pte Ltd.
• Original Assignee: Meridian Innovation Pte Ltd.
• Inventors: KROPELNICKI, Piotr, OCAK, Ilker Ender, PONTIN, Paul Simon
• Granted Patent: US 10,199,424 B1
• Time in Patent Office: Days
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 1/00317 Packaging optical devices
• CPC Class Codes: B81C 2203/0742 Interleave, i.e. simultaneously forming the micromechanical structure and the CMOS circuit
• CPC Class Codes: G01J 2005/123 Thermoelectric array
• CPC Class Codes: G01J 2005/204 prepared by semiconductor processing, e.g. VLSI
• CPC Class Codes: G01J 5/0225 Shape of the cavity itself or of elements contained in or suspended over the cavity
• CPC Class Codes: G01J 5/024 Special manufacturing steps or sacrificial layers or layer structures
• CPC Class Codes: G01J 5/046 Materials; Selection of thermal materials
• CPC Class Codes: G01J 5/048 Protective parts
• CPC Class Codes: G01J 5/12 using thermoelectric elements, e.g. thermocouples
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14629 Reflectors
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/1465 of the hybrid type
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements
• CPC Class Codes: H01L 27/14689 MOS based technologies
• CPC Class Codes: H01L 27/1469 Assemblies, i.e. hybrid integration

Abstract

Device and method of forming a device are disclosed. The device includes a substrate with a transistor component disposed in a transistor region and a micro-electrical mechanical system (MEMS) component disposed on a membrane over a lower sensor cavity in a hybrid region. The MEMS component serves as thermoelectric-based infrared sensor, a thermopile line structure which includes an absorber layer disposed over a portion of oppositely doped first and second line segments. A back-end-of-line (BEOL) dielectric is disposed on the substrate having a plurality of inter layer dielectric (ILD) layers with metal and via levels. The ILD layers include metal lines and via contacts for interconnecting the components of the device. The metal lines in the metal levels are configured to define a BEOL or an upper sensor cavity over the lower sensor cavity, and metal lines of a first metal level of the BEOL dielectric are configured to define a geometry of the MEMS component.

Claims

1. A device comprising:

a substrate including a transistor region and a hybrid region;

a transistor component disposed in the transistor region;

a hybrid component disposed on the substrate in the hybrid region;

a lower sensor cavity in the hybrid region, the lower sensor cavity is disposed over the hybrid component;

a micro-electrical mechanical system (MEMS) component disposed over the lower sensor cavity in the hybrid region; and

a back-end-of-line (BEOL) dielectric disposed on the substrate having a plurality of inter layer dielectric (ILD) layers with metal and via levels, the metal levels include metal lines and the via levels include via contacts for interconnecting the components of the device, wherein the metal lines in the metal levels are configured to define an upper sensor cavity over the lower sensor cavity, and wherein metal lines of a first metal level of the BEOL dielectric are configured to define a geometry of the MEMS component.

2. The device of claim 1 wherein the MEMS component comprises a thermoelectric-based infrared sensor.

3. The device of claim 2 wherein the thermoelectric-based infrared sensor includes a thermopile line structure, wherein the thermopile line structure comprises

a first line segment comprising a first polarity type first line segment;

and

a second line segment comprising a second polarity type second line segment.

4. The device of claim 3 wherein the first and second line segments form a continuous thermopile line structure coupled by a metal contact.

5. The device of claim 2 further comprising an isolation well in the substrate which occupies the hybrid region.

6. The device of claim 5 wherein the BEOL dielectric further comprises a bottom sealing ring formed on a top surface of the BEOL dielectric and surrounding the device.

7. The device of claim 6 further comprising a cap, wherein the cap comprises:

an upper cap portion with an outer surface;

a lower cap portion with an inner surface; and

a top sealing ring disposed on the lower cap portion.

8. The device of claim 7 wherein the cap further comprises an anti-reflective region, wherein the anti-reflective region includes a bottom grating on the inner surface of the cap and a top grating on the outer surface of the cap.

9. The device of claim 8 wherein the hybrid component includes at least one capacitor, wherein the at least one capacitor comprises:

a bottom capacitor electrode disposed over the isolation well, wherein the bottom capacitor electrode is a doped electrode with a first polarity type dopant or an electrode silicide;

a capacitor dielectric disposed over the bottom capacitor electrode;

a top capacitor electrode disposed over the capacitor dielectric, wherein the top capacitor electrode serves as a reflector and is a doped polysilicon with capacitor dopants or an electrode silicide; and

a protection layer disposed over the top capacitor electrode.

10. The device of claim 9 wherein the hybrid component includes a plurality of capacitors, wherein the plurality of capacitors can be connected to each other to create a larger capacitor.

11. The device of claim 8 wherein the hybrid component includes at least one resistor, wherein the at least one resistor is a highly doped polysilicon or silicided polysilicon line structure with a first terminal at a first end and a second terminal at a second end and serves as a reflector of infrared radiation.

12. The device of claim 11 wherein the hybrid component includes a plurality of resistors, wherein the plurality of resistors can be connected to each other to create a larger resistor.

13. The device of claim 8 wherein the hybrid region comprises

a resistor region segment, wherein the resistor region segment includes

at least one resistor, wherein the at least one resistor is a highly doped polysilicon or silicided polysilicon line structure with a first terminal at a first end and a second terminal at a second end and serves as a reflector of infrared radiation, and

resistor fillers disposed in gaps of non-component areas;

and

a capacitor region segment, wherein the capacitor region segment includes

at least one capacitor, wherein the at least one capacitor comprises

a bottom capacitor electrode disposed over the isolation well, wherein the bottom capacitor electrode is a doped electrode with a first polarity type dopant or an electrode silicide,

a capacitor dielectric disposed over the bottom capacitor electrode, and

a top capacitor electrode disposed over the capacitor dielectric, wherein the top capacitor electrode is a doped polysilicon with capacitor dopants or an electrode silicide.

14. The device of claim 13 wherein the capacitor region segment includes a plurality of capacitors, wherein the plurality of capacitors can be connected to each other to create a larger capacitor.

15. The device of claim 13 wherein the resistor region segment includes a plurality of resistors, wherein the plurality of resistors can be connected to each other to create a larger resistor.

21. The device of claim 3 wherein the first and second line segments form a discontinuous thermopile line structure coupled by a metal contact.

22. The device of claim 2 wherein the thermoelectric-based infrared sensor includes a thermopile line structure, the thermopile line structure comprises first and second line units to form a 2-line unit thermopile structure, wherein:

the first line unit comprises a first line unit first line segment and the second line unit comprises a second line unit first line segment, wherein the first line segments of the first and second line units comprise discontinuous first polarity type first line segments disposed on a first line level;

the first line unit comprises a first line unit second line segment and the second line unit comprises a second line unit second line segment, wherein the second line segments of the first and second line units comprise discontinuous second polarity type second line segments disposed on second first line level;

an interline level dielectric layer disposed over the first line segments of the first and second line units which separates the second line segments of the first and second line units;

a first metal contact coupling the first and second line segments of the first line unit; and

a second metal contact coupling the first and second line segments of the second line unit.

23. The device of claim 22 wherein:

the second line segment of the first line unit on the second line level overlays the first line segment of the first line unit on the first line level;

the second line segment of the second line unit on the second line level overlays the first line segment of the first line unit on the first line level; and

the first line unit is disposed adjacent to the second line unit in the hybrid region.

24. The device of claim 2 wherein the thermoelectric-based infrared sensor includes a thermopile line structure comprising N line units, where N≥

1, wherein each of the line units comprises;

a first polarity type first line segment;

a second polarity type second line segment; and

a contact coupling the first and second line segments.

16-20. -20. (canceled)

25. A device comprising:

a substrate with a hybrid region;

a hybrid component disposed on the substrate in the hybrid region;

a lower sensor cavity in the hybrid region, the lower sensor cavity is disposed over the hybrid component;

a micro-electrical mechanical system (MEMS) component disposed over the lower sensor cavity in the hybrid region; and

a back-end-of-line (BEOL) dielectric disposed on the substrate having a plurality of inter layer dielectric (ILD) layers with metal and via levels, the metal levels include metal lines and the via levels include via contacts, wherein the metal lines in the metal levels are configured to define an upper sensor cavity over the lower sensor cavity, and wherein metal lines of a first metal level of the BEOL dielectric are configured to define the MEMS component.