Sensor substrate and method of fabricating same

• US 7,323,142 B2
• Filed: 01/02/2002
• Issued: 01/29/2008
• Est. Priority Date: 09/07/2001
• Status: Expired due to Term

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Shah, Rajiv, Pendo, Shaun, Chernoff, Edward
• Primary Examiner(s): Warden; Jill
• Assistant Examiner(s): HYUN, PAUL SANG HWA
• Application Number:
  US10/038,276
• Publication Number:
  US 20030049166A1
• Time in Patent Office: 2,218 Days
• Field of Search: 422/50, 422/68.1, 422/82.01, 436/149, 436/150, 600/322, 600/365, 600/373, 600/345, 600/347
• US Class Current: 422/82.01
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: H05K 1/0306 Inorganic insulating substrates, e.g. ceramic, glass
• CPC Class Codes: H05K 2201/0175 Inorganic, non-metallic layer, e.g. resist or dielectric for printed capacitor
• CPC Class Codes: H05K 2201/0179 Thin film deposited insulating layer, e.g. inorganic layer for printed capacitor
• CPC Class Codes: H05K 2201/0317 Thin film conductor layer; Thin film passive component
• CPC Class Codes: H05K 2201/09472 Recessed pad for surface mounting recess in pad H05K2201/09745; Recessed electrode of component
• CPC Class Codes: H05K 2203/082 Suction, e.g. for holding solder balls or components
• CPC Class Codes: H05K 2203/085 Using vacuum or low pressure
• CPC Class Codes: H05K 2203/1147 Sealing or impregnating, e.g. of pores
• CPC Class Codes: H05K 2203/1476 Same or similar kind of process performed in phases, e.g. coarse patterning followed by fine patterning
• CPC Class Codes: H05K 2203/1572 Processing both sides of a PCB by the same process; Providing a similar arrangement of components on both sides; Making interlayer connections from two sides
• CPC Class Codes: H05K 2203/308 Sacrificial means, e.g. for temporarily filling a space for making a via or a cavity or for making rigid-flexible PCBs
• CPC Class Codes: H05K 3/28 Applying non-metallic protective coatings H05K3/0091 takes precedence; methods for intermediate insulating layers for build-up multilayer circuits H05K3/4673
• CPC Class Codes: H05K 3/4061 for via connections in inorganic insulating substrates

Abstract

A substrate with hermetically sealed vias extending from one side of the substrate to another and a method for fabricating same. The vias may be filled with a conductive material such as, for example, a fritless ink. The conductive path formed by the conductive material aids in sealing one side of the substrate from another. One side of the substrate may include a sensing element and another side of the substrate may include sensing electronics.

Claims

1. A sensing apparatus comprising:

a substrate composed of alumina and having a first side for a sensing element and a second side for electronics;

a via comprising a linear hollow path formed from the first side of the substrate to the second side of the substrate and filled with an electrically conductive material for making electrical contact from the first side of the substrate to the second side of the substrate; and

a cap covering the via;

wherein the via is hermetically sealed from the first side of the substrate to the second side of the substrate; and

wherein the cap is made from alumina.

2. A sensing apparatus according to claim 1, wherein the electrically conductive material is a fritless ink.

3. A sensing apparatus according to claim 2, wherein the fritless ink is a gold paste.

4. A sensing apparatus according to claim 2, wherein the fritless ink is a platinum paste.

5. A sensing apparatus according to claim 1, wherein the substrate is ceramic insulator.

6. A sensing apparatus according to claim 1, wherein the substrate is substantially 92%-96% alumina.

7. A sensing apparatus according to claim 1, wherein the second side is covered with a lid.

8. A sensing apparatus according to claim 7, wherein the lid is made of gold.

9. A sensing apparatus according to claim 1, wherein the alumina cap is deposited using an ion beam assist deposition process.

10. A sensing apparatus according to claim 1, wherein the via comprises a plurality of vias.

11. A sensing apparatus according to claim 1, wherein the substrate is annealed.

20. A sensing apparatus according to claim 1, wherein the linear hollow path defines a boundary between the electrically conductive material and the substrate.

22. A sensing apparatus according to claim 1, wherein the substrate is insulating.

24. A sensing apparatus according to claim 1, wherein the substrate is non-conducting and non-semiconducting.

12. A sensing apparatus comprising:

a substrate composed of alumina and having a first side and a second side;

a sensor for sensing a biological condition and providing an electrical signals dependent upon the sensed biological condition, the sensor disposed on the first side of the substrate;

electronics for processing electrical signals provided by the sensor, the electronics disposed on the second side of the substrate;

at least one via, each via comprising a linear hollow path formed from the first side of the substrate to the second side of the substrate and filled with an electrically conductive material for making electrical contact from the first side of the substrate to the second side of the substrate,

wherein the via is hermetically sealed from the first side of the substrate to the second side of the substrate.

13. A sensing apparatus according to claim 12, wherein each via comprises a conductive path formed of a single conductive material extending without interruption through the substrate from the first side of the substrate to the second side of the substrate.

14. A sensing apparatus according to claim 13, wherein the single conductive material comprises a flowable conductive filler material that is disposed within the hollow path in a flowable form and hardened within the hollow path of each via to form a solid, filled via.

15. A sensing apparatus according to claim 12, wherein each via comprises a flowable conductive filler material that is disposed within the hollow path in a flowable form and hardened within the hollow path to form a solid, filled via extending, without interruption, from the first side of the substrate to the second side of the substrate.

16. A sensing apparatus according to claim 12, wherein the electrically conductive material is a fritless ink.

17. A sensing apparatus according to claim 16, wherein the fritless ink is a gold paste.

18. A sensing apparatus according to claim 16, wherein the fritless ink is a platinum paste.

19. A sensing apparatus according to claim 12, wherein the substrate is substantially 92%-96% alumina.

21. A sensing apparatus according to claim 12, wherein the linear hollow path defines a boundary between the electrically conductive material and the substrate.

23. A sensing apparatus according to claim 12, wherein the substrate is insulating.

25. A sensing apparatus according to claim 12, wherein the substrate is non-conducting and non-semiconducting.