CHEMICAL SENSOR AND METHOD FOR MANUFACTURING SUCH A CHEMICAL SENSOR

• US 20140225202A1
• Filed: 01/22/2014
• Published: 08/14/2014
• Est. Priority Date: 01/31/2013
• Status: Abandoned Application

• Current Assignee: Sensirion AG (Sensirion Holding AG)
• Original Assignee: Sensirion AG (Sensirion Holding AG)
• Inventors: MAYER, Felix, LECHNER, Moritz, KUEMIN, Cyrill, HUMMEL, Rene, SUNIER, Robert
• Application Number:
  US14/160,789
• Publication Number:
  US 20140225202A1
• Time in Patent Office: Days
• US Class Current: 257/414
• CPC Class Codes: G01N 27/128 Microapparatus
• CPC Class Codes: G01N 27/18 caused by changes in the thermal conductivity of a surrounding material to be tested G01N27/20 takes precedence
• CPC Class Codes: G01N 27/26 by investigating electrochemical variables; by using electrolysis or electrophoresis
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics

Abstract

The invention relates to a chemical sensor (1) comprising a substrate layer (2) having a front surface (2.1) and a back surface (2.2) and a sensing layer (3) arranged on the front surface (2.1) of the substrate layer (2), the sensing layer (3) comprising a sensing element (4) and the substrate layer (2) being provided with a well (5) in the back surface (2.2) to a form a membrane (6) that incorporates the sensing element (4), wherein the substrate layer (2) is provided with contact pads (10) on the back surface (2.2) and with vias (11) extending from the front surface (2.1) to the back surface (2.2) for electrically connecting the sensing element (4) with the contact pads (10), wherein a handling layer (17) is provided on top of the sensing layer (3), the handling layer (17) surrounding the sensing element (4), and wherein the thickness (d1) of the handling layer (17) is larger than the thickness (d2) of the substrate layer (2). The invention furthermore relates to a method for manufacturing such a chemical sensor (1).

Claims

1. A chemical sensor comprising a substrate layer (2) having a front surface (2.1) and a back surface (2.2) and a sensing layer (3) arranged on the front surface (2.1) of the substrate layer (2), the sensing layer (3) comprising a sensing element (4) and the substrate layer (2) being provided with a well (5) in the back surface (2.2) to a form a membrane (6) that incorporates the sensing element (4), characterized in that

the substrate layer (2) is provided with contact pads (10) on the back surface (2.2) and with vias (11) extending from the front surface (2.1) to the back surface (2.2) for electrically connecting the sensing element (4) with the contact pads (10),

wherein a handling layer (17) is provided on top of the sensing layer (3), the handling layer (17) surrounding the sensing element (4), and

wherein the thickness (d1) of the handling layer (17) is larger than the thickness (d2) of the substrate layer (2).

2. The chemical sensor according to claim 1, wherein the thickness (d1) of the handling layer (17) is at least 50 per cent of the thickness (d3) of the entire chemical sensor (1).

3. The chemical sensor according to claim 1, wherein the thickness (d1) of the handling layer (17) is in the range from 200 to 500 microns.

4. The chemical sensor according to claim 1, wherein the thickness (d2) of the substrate layer (2) is less than the lateral elongation of the membrane (6).

5. The chemical sensor according to claim 1, wherein the thickness (d2) of the substrate layer (2) is in the range from 50 to 200 microns.

6. The chemical sensor according to claim 1, wherein the handling layer (17) is made of silicon or glass.

7. The chemical sensor according to claim 1, wherein the front surface (17.1) of the handling layer (17) is smooth.

8. A method for manufacturing a chemical sensor according to claim 1, the method comprises the following steps:

forming a sensing layer (3) that includes the sensing element (4) on a bulk substrate,

forming a handling layer (17) on top of the sensing layer (3) that surrounds the sensing element (4),

reducing the thickness of the bulk substrate to a thickness (d2) that is lesser than the thickness (d1) of the handling layer (17), thereby forming the substrate layer (2) from the bulk substrate,

forming vias (11) in the substrate layer (2), the vias (11) extending from the front surface (2.1) to the back surface (2.2) of the substrate layer (2), and

forming a well (5) in the back surface (2.2) of the substrate layer (2) to leave a membrane (6) that incorporates the sensing element (4).

9. The method according to claim 8, wherein the thickness of the bulk substrate is reduced to a thickness (d2) to form the substrate layer (2) such that the thickness (d1) of the handling layer (17) is at least 50 per cent of the thickness (d3) of the entire chemical sensor (1).

10. The method according to claim 8, wherein the thickness (d1) of the handling layer (17) is in the range from 200 to 500 microns.

11. The method according to claim 8, wherein the thickness of the bulk substrate is reduced to a thickness (d2) that is in the range from 50 to 200 microns to form the substrate layer (2).

12. The method according to claim 8, wherein the well (5) is formed such in the back surface (2.2) of the substrate layer (2) that the lateral elongation of the membrane (6) is larger than the thickness (d2) of the substrate layer (2).

13. The method according to claim 8, wherein for forming the handling layer (17) on top of the sensing layer (3) an adhesive layer (18) is provided on top of the sensing layer (3), the adhesive layer (18) surrounding the sensing element (4) and connecting the handling layer (17) to the top of the sensing layer (3).

14. The method according to claim 8, wherein the handling layer (17) is made of silicon or glass.

15. The method according to claim 8, where the top of the handling layer (17) is grinded to form a smooth front surface (17.1) of the handling layer.