Flow sensor package

Patent metadata

Field	Value
Publication number	US-10151612-B2
Application number	US-201514953914-A
Country	US
Kind code	B2
Filing date	Nov 30, 2015
Priority date	Dec 8, 2014
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

A flow sensor package comprises a chip comprising a sensitive structure for sensing the flow of a fluid and an encapsulation at least partly encapsulating the chip. A recess in the encapsulation contributes to a flow channel for guiding the fluid, which recess exposes at least the sensitive structure of the chip from the encapsulation, and which recess extends beyond an edge of the chip.

First claim

The invention claimed is:

1. Flow sensor package, comprising
a chip comprising a sensitive structure for sensing the flow of a fluid,
an encapsulation at least partly encapsulating the chip, and
a recess in the encapsulation contributing to a flow channel for guiding the fluid, which recess exposes at least the sensitive structure of the chip from the encapsulation,
wherein the chip has a front side and side faces,
wherein the sensitive structure is arranged at the front side of the chip,
wherein the recess exposes a strip of the front side of the chip from the encapsulation including the sensitive structure,
wherein a transition between the front side of the chip and one of its side faces defines an edge of the chip the recess extends beyond,
wherein a bottom of the recess comprises a first portion formed by the front side of the chip and at least one second portion formed by the encapsulation,
wherein the first portion and the at least one second portion are arranged at the same level.

2. Flow sensor package according to claim 1 ,
wherein the sensitive structure comprises a heater and at least one temperature sensor next to the heater,
wherein the recess has a longitudinal extension exceeding its lateral extension which longitudinal extension defines a flow direction for the fluid, and
wherein the recess is arranged with respect to the sensitive structure such that the fluid passes a sequence of the heater and the at least one temperature sensor in flow direction.

3. Flow sensor package according to claim 1 , comprising a carrier for the chip,
wherein the chip is electrically connected to the carrier by means of bond wires,
wherein the bond wires are embedded in the encapsulation.

4. Flow sensor package according to claim 3 ,
wherein a front side of the chip at which the sensitive structure is arranged has a longitudinal extension and a lateral extension,
wherein a longitudinal position of the sensitive structure separates the front side of the chip in an upper area and a lower area,
wherein the upper area is smaller than the lower area,
wherein the bond wires exclusively extend from the lower area, and
in particular wherein the chip is a semiconductor chip and electronic circuitry is integrated into the lower area for processing a signal supplied by the sensitive structure.

5. Flow sensor package according to claim 4 ,
wherein the longitudinal extension of the front side of the chip exceeds its lateral extension, and
wherein the recess extends across the front side of the chip in parallel to its lateral extension.

6. Flow sensor package according to claim 3 ,
wherein the flow sensor package has a cuboid shape with a longitudinal extension, a lateral extension and a height, the longitudinal extension and the lateral extension defining a front side of the flow sensor package the recess is arranged in,
wherein the recess extends in parallel to the lateral extension of the flow sensor package,
wherein a longitudinal position of the recess separates a volume of the flow sensor package in an upper volume and a lower volume,
wherein the upper volume is smaller than the lower volume,
wherein the bond wires are exclusively arranged in the lower volume.

7. Flow sensor package according to claim 6 ,
wherein the carrier comprises contact pads for electrically connecting the flow sensor package from the outside, which contact pads are exposed from the encapsulation at one or more of a back side of the flow sensor package opposite its front side and/or at side faces of the flow sensor package, and
wherein the contact pads located in the upper volume are dummy contact pads.

8. Flow sensor package according to claim 1 ,
wherein the recess extends beyond opposite edges of the chip.

9. Flow sensor package according to claim 1 ,
wherein the flow sensor package has a front side and side faces defined by the encapsulation,
wherein the recess is arranged in the front side of the flow sensor package,
wherein a transition between the front side and each side face defines an edge of the flow sensor package.

10. Flow sensor package according to claim 9 ,
wherein the recess extends completely across the flow sensor package between opposite edges thereof.

11. Flow sensor package according to claim 9 ,
wherein a longitudinal extension of the recess terminates prior to reaching opposite edges of the flow sensor package.

12. Flow sensor arrangement comprising,
a flow sensor package according to claim 1 , and
a flow channel lid comprising a cover, which cover at least partly covers the recess in the encapsulation for defining the flow channel for guiding a fluid.

13. Flow sensor arrangement according to claim 12 , comprising,
a protrusion extending from a back side of the cover,
wherein the protrusion extends into the recess of the flow sensor package for forming the flow channel between the protrusion and the flow sensor package.

14. Flow sensor arrangement according to claim 12 ,
wherein the cover exceeds a front side of the flow sensor package to be mounted to in size, and in particular wherein the cover is of rectangular shape.

15. Flow sensor arrangement according to claim 14 ,
wherein the flow channel lid comprises pins extending from the back side of the cover for embracing the flow sensor package,
and in particular wherein the pins extend from corners of the cover,
and in particular wherein the pins are manufactured as one piece together with the cover.

16. Flow sensor arrangement according to claim 15 ,
wherein each pin has a length computed from the back side of the cover that exceeds a height of the flow sensor package.

17. Flow sensor arrangement according to claim 12 ,
wherein the flow channel lid comprises an inlet tube and an outlet tube for the flow channel,
and in particular wherein the inlet tube and the outlet tube extend from a front side of the cover,
and in particular wherein the inlet tube and the outlet tube are manufactured as one piece together with the cover.

18. Flow sensor arrangement according to claim 17 ,
wherein at least one of the inlet tube and the outlet tube, and preferably both the inlet tube and the outlet tube, comprise/s a flow resistance, and
in particular wherein the flow resistance is embodied as a reduction of an inner diameter of the respective tube.

19. Flow sensor arrangement according to claim 12 ,
wherein the flow channel lid is glued with its back side to the front side of the flow sensor package.

Assignees

• Sensirion Ag

Inventors

• Hunziker Werner
• Hornung Mark
• Monnin Eric

Classifications

• H10P54/00

  Cutting or separating of wafers, substrates or parts of devices · CPC title

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W90/754

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W74/111

  the semiconductor body being completely enclosed · CPC title

• H10W74/10

  characterised by their shape or disposition · CPC title