Substrates having through-hole vias and method of making same

• US 20040043423A1
• Filed: 03/19/2003
• Published: 03/04/2004
• Est. Priority Date: 09/20/2000
• Status: Abandoned Application

• Current Assignee: MOLECULAR REFLECTIONS/DR. MICHAEL NERENBERG AND DR. ROBERT PETCAVICH, ProterixBio, Inc.
• Original Assignee: Molecular Reflections, Inc.
• Inventors: Liu, Kelvin, Collins, Boyce E., Bellew, Colby
• Application Number:
  US10/392,446
• Publication Number:
  US 20040043423A1
• Time in Patent Office: Days
• US Class Current: 435/7.1
• CPC Class Codes: B06B 1/0292 Electrostatic transducers, e.g. electret-type
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/0255 (Bio)chemical reactions, e.g. on biosensors
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 2291/02818 Density, viscosity
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 29/02 Analysing fluids using acoustic emission techniques G01N29/14 ; constructional or flow details for analysing fluids G01N29/222; optoacoustic fluid cells G01N29/2425
• CPC Class Codes: G01N 29/022 Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices microdevices per se B81B
• CPC Class Codes: G01N 29/222 Constructional or flow details for analysing fluids optoacoustic fluid cells G01N29/2425
• CPC Class Codes: G01N 29/223 Supports, positioning or alignment in fixed situation mounting transducers per se G10K11/004
• CPC Class Codes: Y10T 29/49126 Assembling bases
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49169 Assembling electrical component directly to terminal or elongated conductor
• CPC Class Codes: Y10T 29/53052 including position sensor

Abstract

A sensor assembly for sensors such as microfabricated resonant sensors is disclosed. The disclosed assembly provides improved performance of the sensors by providing a thermally insensitive environment and short pathways for signals to travel to processing components. Further, the assembly provide modular construction for the sensors and housing modules, thereby allowing replacement of the sensors at a lower cost. The assembly includes a sensor module including a sensor formed on a conductive substrate with a cavity formed on one surface. The substrate has conductive vias extending from the cavity to a second surface of the substrate. A housing assembly accommodates the sensor and includes a rigid housing, preferably made from a ceramic. An electronic component, such as an amplifier, is mounted on the rigid housing. The electronic component electrically engages the vias substantially at the second surface of the substrate. The electronic component receive signals from the sensor through the vias. The signals are then processed through an amplifier and a digital signal processor using a modified periodogram.

Claims

1. A sensor element, comprising:

a substrate having at least one cavity formed on a first surface;

a membrane on said first surface enclosing said cavity and including a first electrode;

a second electrode spaced apart from the first electrode; and

at least one via extending from the cavity to a second surface of the substrate, the second surface being opposite of said first surface;

wherein said via includes at least two coaxial channels.

2. The sensor element according to claim 1, wherein said coaxial channels include an outer conductive channel and an inner conductive channel.

3. The sensor element according to claim 1, wherein coaxial channels include an outer conductive channel and an inner fluid channel.

4. The sensor element according to claim 3, wherein said inner fluid channel is adapted to vent said cavity to atmosphere.

5. The sensor element according to claim 1, wherein said coaxial channels are separated by an insulating layer.

6. The sensor element according to claim 1, wherein said cavity is substantially evacuated.

7. A method of forming a substrate for a sensor element, comprising:

a) forming a via from a first surface of the substrate to a second surface of the substrate, the second surface being opposite said first surface;

b) coating the walls of said via with a first insulating layer; and

c) forming a first conductive layer over said first insulating layer, said first conductive layer extending substantially from the first surface to the second surface, and said conductive layer having a hollow, central channel therethrough.

8. The method according to claim 7, wherein step a) includes electrochemically etching said substrate.

9. The method according to claim 7, wherein step b) includes growing a conformal insulating layer.

10. The method according to claim 7, wherein step c) comprises:

filling a central region through said insulating layer with a conductive material; and

etching said conductive material to form said hollow central channel therethrough.

11. The method according to claim 7, further comprising:

d) coating the walls of said hollow, central channel with a second insulating layer, thereby forming a hollow insulated channel through said first conductive layer.

12. The method according to claim 11, further comprising:

e) filling said insulated channel with a conductive material, thereby forming a second conductive channel through said via.

13. A substrate for a sensor element, comprising:

a substrate having at least one via formed therein, said via extending substantially perpendicular to a plane of said substrate;

an outer channel formed in said via, said outer channel forming an annular sleeve; and

an inner channel formed in said via, said inner channel being substantially coaxial with said outer channel

14. The substrate according to claim 13, wherein said outer channel is a conductive channel.

15. The substrate according to claim 13, wherein said inner channel is a fluid channel.