SEMICONDUCTOR SENSOR AND METHOD OF MANUFACTURING THE SAME

• US 20180057354A1
• Filed: 10/14/2016
• Published: 03/01/2018
• Est. Priority Date: 08/26/2016
• Status: Active Grant

• Current Assignee: United Microelectronics Corporation
• Original Assignee: United Microelectronics Corporation
• Inventors: Hu, Chih-Fan, Lee, Chia-Wei, Hsu, Chang-Sheng, Chen, Weng-Yi
• Granted Patent: US 10,640,368 B2
• Time in Patent Office: Days
• CPC Class Codes: B81B 2201/0214 Biosensors; Chemical sensors
• CPC Class Codes: B81B 2201/0292 Sensors not provided for in B81B2201/0207 - B81B2201/0285
• CPC Class Codes: B81B 2207/012 the micromechanical device and the control or processing electronics being separate parts in the same package
• CPC Class Codes: B81B 2207/07 Interconnects
• CPC Class Codes: B81B 3/0081 Thermal properties
• CPC Class Codes: B81B 7/007 Interconnections between the MEMS and external electrical signals
• CPC Class Codes: B81C 1/00301 Connecting electric signal lines from the MEMS device with external electrical signal lines, e.g. through vias
• CPC Class Codes: G01N 27/128 Microapparatus
• CPC Class Codes: H01L 2224/48464 the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball

Abstract

A semiconductor sensor, comprising a gas-sensing device and an integrated circuit electrically connected to the gas-sensing device, is provided. The gas-sensing device includes a substrate having a sensing area and an interconnection area in the vicinity of the sensing area, an inter-metal dielectric (IMD) layer formed above the substrate in the sensing area and in the interconnection area, and an interconnect structure formed in the interconnection area. The interconnect structure includes a tungsten layer buried in the IMD layer, wherein part of a top surface of the tungsten layer is exposed by at least a via. The interconnect structure further includes a platinum layer formed in said at least the via, wherein the platinum (Pt) layer directly contacts the top surface of the tungsten layer.

Claims

1. A semiconductor sensor, comprising a gas-sensing device and an integrated circuit electrically connected to the gas-sensing device, and the gas-sensing device comprising:

a substrate having a sensing area and an interconnection area in the vicinity of the sensing area;

an inter-metal dielectric (IMD) layer formed above the substrate in the sensing area and in the interconnection area; and

an interconnect structure formed in the interconnection area, and the interconnect structure comprising;

a tungsten layer buried in the IMD layer and part of a top surface of the tungsten layer being exposed by at least a via; and

a platinum layer formed in said at least the via,

wherein the platinum (Pt) layer directly contacts said part of the top surface of the tungsten layer.

2. The semiconductor sensor according to claim 1, wherein the platinum layer further directly contact sidewalls of said at least the via.

3. The semiconductor sensor according to claim 1, wherein the interconnect structure further comprises a TiO₂ layer formed on the IMD layer adjacent to said at least the via, and the platinum layer is also directly formed on the TiO₂ layer above the IMD layer.

4. The semiconductor sensor according to claim 1, wherein the interconnect structure further comprises a TiO₂ layer formed on sidewalls of said at least the via, and the platinum layer is formed on the TiO₂ layer and directly contacts said part of the top surface of the tungsten layer.

5. The semiconductor sensor according to claim 1, wherein the gas-sensing device further comprises a sensing electrode in the sensing area, and the sensing electrode is formed on the IMD layer.

6. The semiconductor sensor according to claim 5, wherein the sensing electrode comprises:

a patterned TiO₂ layer formed on the IMD layer; and

a patterned platinum (Pt) layer formed on the patterned TiO₂ layer.

7. The semiconductor sensor according to claim 6, wherein the platinum layer of the interconnect structure and the patterned Pt layer of the sensing electrode are physically connected.

8. The semiconductor sensor according to claim 5, wherein the interconnect structure in the interconnection area further comprise:

a first TiO₂-patterned portion formed on the top surface of the tungsten layer and exposing said part of the top surface of the tungsten layer corresponding to said at least the via; and

a first Pt-patterned portion formed on the first TiO₂-patterned portion and directly contacting said part of the top surface of the tungsten layer;

wherein the platinum layer in said at least the via directly contacts the first Pt-patterned portion.

9. The semiconductor sensor according to claim 8, wherein the gas-sensing device in the sensing area further comprises:

a second TiO₂-patterned portion buried in the IMD layer and positioned below the sensing electrode; and

a second Pt-patterned portion directly formed on the second TiO₂-patterned portion,

wherein the second Pt-patterned portion acts as a heater of the gas-sensing device.

10. The semiconductor sensor according to claim 9, wherein a portion of the substrate in the sensing area is removed.

11. The semiconductor sensor according to claim 5, wherein the gas-sensing device further comprises a gas sensing layer formed on the sensing electrode so as to span the sensing electrode.

12. The semiconductor sensor according to claim 1, wherein the gas-sensing device further comprises a heater in the sensing area, and the heater is buried in the IMD layer and formed correspondingly to the sensing electrode.

13. The semiconductor sensor according to claim 12, wherein the heater in the IMD layer is electrically connected to the tungsten layer in the interconnection area.

14. The semiconductor sensor according to claim 1, further comprising a passivation layer formed on the IMD layer to fill up said at least the via in the interconnection area and expose the sensing electrode in the sensing area.

15. The semiconductor sensor according to claim 1, wherein the integrated circuit is positioned between the substrate and the gas-sensing device.

16. The semiconductor sensor according to claim 1, wherein the gas-sensing device and the integrated circuit are formed as different chips and electrically connected to each other by wire bonding.

17. A method of manufacturing a semiconductor sensor, comprising forming a gas-sensing device and an integrated circuit and electrically connecting the gas-sensing device to the integrated circuit, and a method of manufacturing the gas-sensing device comprising:

providing a substrate having a sensing area and an interconnection area in the vicinity of the sensing area;

forming an inter-metal dielectric (IMD) layer above the substrate in the sensing area and in the interconnection area; and

forming an interconnect structure in the interconnection area, comprising;

forming a tungsten layer in the IMD layer, and part of a top surface of the tungsten layer being exposed by at least a via; and

forming a platinum layer in said at least the via, wherein the platinum (Pt) layer directly contacts said part of the top surface of the tungsten layer.

18. The method according to claim 17, wherein forming the interconnect structure in the interconnection area further comprises:

forming a titanium layer on the IMD layer;

oxidizing the titanium layer at 300°

to 450°

to form a TiO2 layer;

etching the TiO₂ layer and the IMD layer to form said at least the via to expose said part of the top surface of the tungsten layer; and

forming the platinum layer on the TiO₂ layer and sidewalls of said at least the via, and directly contacting said part of the top surface of the tungsten layer.

19. The method according to claim 17, wherein forming the interconnect structure in the interconnection area further comprises:

etching the IMD layer to form said at least the via to expose said part of the top surface of the tungsten layer;

forming a titanium layer on the IMD layer and extending as a Ti-liner in said at least the via;

oxidizing the titanium layer at 300°

C. to 450°

C. to form a TiO₂ layer on the IMD layer and a TiO₂-liner in said at least the via;

removing a bottom portion of the TiO₂-liner to expose said part of the top surface of the tungsten layer; and

forming the platinum layer on the TiO₂ layer and extending to said at least the via to form a Pt-liner in said at least the via;

wherein the Pt-liner in said at least the via directly contact said part of the top surface of the tungsten layer.

20. The method according to claim 17, wherein the method of manufacturing the gas-sensing device further comprises forming a sensing electrode on the IMD layer in the sensing area, wherein the sensing electrode comprises:

a patterned TiO₂ layer formed on the IMD layer; and

a patterned platinum (Pt) layer formed on the patterned TiO₂ layer.

21. The method according to claim 20, wherein the platinum layer of the interconnect structure and the patterned Pt layer of the sensing electrode are physically connected.